1// -*- C++ -*-
2//===-------------------------- algorithm ---------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_ALGORITHM
12#define _LIBCPP_ALGORITHM
13
14/*
15    algorithm synopsis
16
17#include <initializer_list>
18
19namespace std
20{
21
22template <class InputIterator, class Predicate>
23    bool
24    all_of(InputIterator first, InputIterator last, Predicate pred);
25
26template <class InputIterator, class Predicate>
27    bool
28    any_of(InputIterator first, InputIterator last, Predicate pred);
29
30template <class InputIterator, class Predicate>
31    bool
32    none_of(InputIterator first, InputIterator last, Predicate pred);
33
34template <class InputIterator, class Function>
35    Function
36    for_each(InputIterator first, InputIterator last, Function f);
37
38template<class InputIterator, class Size, class Function>
39    InputIterator for_each_n(InputIterator first, Size n, Function f); // C++17
40
41template <class InputIterator, class T>
42    InputIterator
43    find(InputIterator first, InputIterator last, const T& value);
44
45template <class InputIterator, class Predicate>
46    InputIterator
47    find_if(InputIterator first, InputIterator last, Predicate pred);
48
49template<class InputIterator, class Predicate>
50    InputIterator
51    find_if_not(InputIterator first, InputIterator last, Predicate pred);
52
53template <class ForwardIterator1, class ForwardIterator2>
54    ForwardIterator1
55    find_end(ForwardIterator1 first1, ForwardIterator1 last1,
56             ForwardIterator2 first2, ForwardIterator2 last2);
57
58template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
59    ForwardIterator1
60    find_end(ForwardIterator1 first1, ForwardIterator1 last1,
61             ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
62
63template <class ForwardIterator1, class ForwardIterator2>
64    ForwardIterator1
65    find_first_of(ForwardIterator1 first1, ForwardIterator1 last1,
66                  ForwardIterator2 first2, ForwardIterator2 last2);
67
68template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
69    ForwardIterator1
70    find_first_of(ForwardIterator1 first1, ForwardIterator1 last1,
71                  ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
72
73template <class ForwardIterator>
74    ForwardIterator
75    adjacent_find(ForwardIterator first, ForwardIterator last);
76
77template <class ForwardIterator, class BinaryPredicate>
78    ForwardIterator
79    adjacent_find(ForwardIterator first, ForwardIterator last, BinaryPredicate pred);
80
81template <class InputIterator, class T>
82    typename iterator_traits<InputIterator>::difference_type
83    count(InputIterator first, InputIterator last, const T& value);
84
85template <class InputIterator, class Predicate>
86    typename iterator_traits<InputIterator>::difference_type
87    count_if(InputIterator first, InputIterator last, Predicate pred);
88
89template <class InputIterator1, class InputIterator2>
90    pair<InputIterator1, InputIterator2>
91    mismatch(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2);
92
93template <class InputIterator1, class InputIterator2>
94    pair<InputIterator1, InputIterator2>
95    mismatch(InputIterator1 first1, InputIterator1 last1,
96             InputIterator2 first2, InputIterator2 last2); // **C++14**
97
98template <class InputIterator1, class InputIterator2, class BinaryPredicate>
99    pair<InputIterator1, InputIterator2>
100    mismatch(InputIterator1 first1, InputIterator1 last1,
101             InputIterator2 first2, BinaryPredicate pred);
102
103template <class InputIterator1, class InputIterator2, class BinaryPredicate>
104    pair<InputIterator1, InputIterator2>
105    mismatch(InputIterator1 first1, InputIterator1 last1,
106             InputIterator2 first2, InputIterator2 last2,
107             BinaryPredicate pred); // **C++14**
108
109template <class InputIterator1, class InputIterator2>
110    bool
111    equal(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2);
112
113template <class InputIterator1, class InputIterator2>
114    bool
115    equal(InputIterator1 first1, InputIterator1 last1,
116          InputIterator2 first2, InputIterator2 last2); // **C++14**
117
118template <class InputIterator1, class InputIterator2, class BinaryPredicate>
119    bool
120    equal(InputIterator1 first1, InputIterator1 last1,
121          InputIterator2 first2, BinaryPredicate pred);
122
123template <class InputIterator1, class InputIterator2, class BinaryPredicate>
124    bool
125    equal(InputIterator1 first1, InputIterator1 last1,
126          InputIterator2 first2, InputIterator2 last2,
127          BinaryPredicate pred); // **C++14**
128
129template<class ForwardIterator1, class ForwardIterator2>
130    bool
131    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
132                   ForwardIterator2 first2);
133
134template<class ForwardIterator1, class ForwardIterator2>
135    bool
136    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
137                   ForwardIterator2 first2, ForwardIterator2 last2); // **C++14**
138
139template<class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
140    bool
141    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
142                   ForwardIterator2 first2, BinaryPredicate pred);
143
144template<class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
145    bool
146    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
147                   ForwardIterator2 first2, ForwardIterator2 last2,
148                   BinaryPredicate pred);  // **C++14**
149
150template <class ForwardIterator1, class ForwardIterator2>
151    ForwardIterator1
152    search(ForwardIterator1 first1, ForwardIterator1 last1,
153           ForwardIterator2 first2, ForwardIterator2 last2);
154
155template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
156    ForwardIterator1
157    search(ForwardIterator1 first1, ForwardIterator1 last1,
158           ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
159
160template <class ForwardIterator, class Size, class T>
161    ForwardIterator
162    search_n(ForwardIterator first, ForwardIterator last, Size count, const T& value);
163
164template <class ForwardIterator, class Size, class T, class BinaryPredicate>
165    ForwardIterator
166    search_n(ForwardIterator first, ForwardIterator last,
167             Size count, const T& value, BinaryPredicate pred);
168
169template <class InputIterator, class OutputIterator>
170    OutputIterator
171    copy(InputIterator first, InputIterator last, OutputIterator result);
172
173template<class InputIterator, class OutputIterator, class Predicate>
174    OutputIterator
175    copy_if(InputIterator first, InputIterator last,
176            OutputIterator result, Predicate pred);
177
178template<class InputIterator, class Size, class OutputIterator>
179    OutputIterator
180    copy_n(InputIterator first, Size n, OutputIterator result);
181
182template <class BidirectionalIterator1, class BidirectionalIterator2>
183    BidirectionalIterator2
184    copy_backward(BidirectionalIterator1 first, BidirectionalIterator1 last,
185                  BidirectionalIterator2 result);
186
187template <class ForwardIterator1, class ForwardIterator2>
188    ForwardIterator2
189    swap_ranges(ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2);
190
191template <class ForwardIterator1, class ForwardIterator2>
192    void
193    iter_swap(ForwardIterator1 a, ForwardIterator2 b);
194
195template <class InputIterator, class OutputIterator, class UnaryOperation>
196    OutputIterator
197    transform(InputIterator first, InputIterator last, OutputIterator result, UnaryOperation op);
198
199template <class InputIterator1, class InputIterator2, class OutputIterator, class BinaryOperation>
200    OutputIterator
201    transform(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2,
202              OutputIterator result, BinaryOperation binary_op);
203
204template <class ForwardIterator, class T>
205    void
206    replace(ForwardIterator first, ForwardIterator last, const T& old_value, const T& new_value);
207
208template <class ForwardIterator, class Predicate, class T>
209    void
210    replace_if(ForwardIterator first, ForwardIterator last, Predicate pred, const T& new_value);
211
212template <class InputIterator, class OutputIterator, class T>
213    OutputIterator
214    replace_copy(InputIterator first, InputIterator last, OutputIterator result,
215                 const T& old_value, const T& new_value);
216
217template <class InputIterator, class OutputIterator, class Predicate, class T>
218    OutputIterator
219    replace_copy_if(InputIterator first, InputIterator last, OutputIterator result, Predicate pred, const T& new_value);
220
221template <class ForwardIterator, class T>
222    void
223    fill(ForwardIterator first, ForwardIterator last, const T& value);
224
225template <class OutputIterator, class Size, class T>
226    OutputIterator
227    fill_n(OutputIterator first, Size n, const T& value);
228
229template <class ForwardIterator, class Generator>
230    void
231    generate(ForwardIterator first, ForwardIterator last, Generator gen);
232
233template <class OutputIterator, class Size, class Generator>
234    OutputIterator
235    generate_n(OutputIterator first, Size n, Generator gen);
236
237template <class ForwardIterator, class T>
238    ForwardIterator
239    remove(ForwardIterator first, ForwardIterator last, const T& value);
240
241template <class ForwardIterator, class Predicate>
242    ForwardIterator
243    remove_if(ForwardIterator first, ForwardIterator last, Predicate pred);
244
245template <class InputIterator, class OutputIterator, class T>
246    OutputIterator
247    remove_copy(InputIterator first, InputIterator last, OutputIterator result, const T& value);
248
249template <class InputIterator, class OutputIterator, class Predicate>
250    OutputIterator
251    remove_copy_if(InputIterator first, InputIterator last, OutputIterator result, Predicate pred);
252
253template <class ForwardIterator>
254    ForwardIterator
255    unique(ForwardIterator first, ForwardIterator last);
256
257template <class ForwardIterator, class BinaryPredicate>
258    ForwardIterator
259    unique(ForwardIterator first, ForwardIterator last, BinaryPredicate pred);
260
261template <class InputIterator, class OutputIterator>
262    OutputIterator
263    unique_copy(InputIterator first, InputIterator last, OutputIterator result);
264
265template <class InputIterator, class OutputIterator, class BinaryPredicate>
266    OutputIterator
267    unique_copy(InputIterator first, InputIterator last, OutputIterator result, BinaryPredicate pred);
268
269template <class BidirectionalIterator>
270    void
271    reverse(BidirectionalIterator first, BidirectionalIterator last);
272
273template <class BidirectionalIterator, class OutputIterator>
274    OutputIterator
275    reverse_copy(BidirectionalIterator first, BidirectionalIterator last, OutputIterator result);
276
277template <class ForwardIterator>
278    ForwardIterator
279    rotate(ForwardIterator first, ForwardIterator middle, ForwardIterator last);
280
281template <class ForwardIterator, class OutputIterator>
282    OutputIterator
283    rotate_copy(ForwardIterator first, ForwardIterator middle, ForwardIterator last, OutputIterator result);
284
285template <class RandomAccessIterator>
286    void
287    random_shuffle(RandomAccessIterator first, RandomAccessIterator last); // deprecated in C++14, removed in C++17
288
289template <class RandomAccessIterator, class RandomNumberGenerator>
290    void
291    random_shuffle(RandomAccessIterator first, RandomAccessIterator last,
292                   RandomNumberGenerator& rand);  // deprecated in C++14, removed in C++17
293
294template<class PopulationIterator, class SampleIterator,
295         class Distance, class UniformRandomBitGenerator>
296    SampleIterator sample(PopulationIterator first, PopulationIterator last,
297                          SampleIterator out, Distance n,
298                          UniformRandomBitGenerator&& g); // C++17
299
300template<class RandomAccessIterator, class UniformRandomNumberGenerator>
301    void shuffle(RandomAccessIterator first, RandomAccessIterator last,
302                 UniformRandomNumberGenerator&& g);
303
304template <class InputIterator, class Predicate>
305    bool
306    is_partitioned(InputIterator first, InputIterator last, Predicate pred);
307
308template <class ForwardIterator, class Predicate>
309    ForwardIterator
310    partition(ForwardIterator first, ForwardIterator last, Predicate pred);
311
312template <class InputIterator, class OutputIterator1,
313          class OutputIterator2, class Predicate>
314    pair<OutputIterator1, OutputIterator2>
315    partition_copy(InputIterator first, InputIterator last,
316                   OutputIterator1 out_true, OutputIterator2 out_false,
317                   Predicate pred);
318
319template <class ForwardIterator, class Predicate>
320    ForwardIterator
321    stable_partition(ForwardIterator first, ForwardIterator last, Predicate pred);
322
323template<class ForwardIterator, class Predicate>
324    ForwardIterator
325    partition_point(ForwardIterator first, ForwardIterator last, Predicate pred);
326
327template <class ForwardIterator>
328    bool
329    is_sorted(ForwardIterator first, ForwardIterator last);
330
331template <class ForwardIterator, class Compare>
332    bool
333    is_sorted(ForwardIterator first, ForwardIterator last, Compare comp);
334
335template<class ForwardIterator>
336    ForwardIterator
337    is_sorted_until(ForwardIterator first, ForwardIterator last);
338
339template <class ForwardIterator, class Compare>
340    ForwardIterator
341    is_sorted_until(ForwardIterator first, ForwardIterator last, Compare comp);
342
343template <class RandomAccessIterator>
344    void
345    sort(RandomAccessIterator first, RandomAccessIterator last);
346
347template <class RandomAccessIterator, class Compare>
348    void
349    sort(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
350
351template <class RandomAccessIterator>
352    void
353    stable_sort(RandomAccessIterator first, RandomAccessIterator last);
354
355template <class RandomAccessIterator, class Compare>
356    void
357    stable_sort(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
358
359template <class RandomAccessIterator>
360    void
361    partial_sort(RandomAccessIterator first, RandomAccessIterator middle, RandomAccessIterator last);
362
363template <class RandomAccessIterator, class Compare>
364    void
365    partial_sort(RandomAccessIterator first, RandomAccessIterator middle, RandomAccessIterator last, Compare comp);
366
367template <class InputIterator, class RandomAccessIterator>
368    RandomAccessIterator
369    partial_sort_copy(InputIterator first, InputIterator last,
370                      RandomAccessIterator result_first, RandomAccessIterator result_last);
371
372template <class InputIterator, class RandomAccessIterator, class Compare>
373    RandomAccessIterator
374    partial_sort_copy(InputIterator first, InputIterator last,
375                      RandomAccessIterator result_first, RandomAccessIterator result_last, Compare comp);
376
377template <class RandomAccessIterator>
378    void
379    nth_element(RandomAccessIterator first, RandomAccessIterator nth, RandomAccessIterator last);
380
381template <class RandomAccessIterator, class Compare>
382    void
383    nth_element(RandomAccessIterator first, RandomAccessIterator nth, RandomAccessIterator last, Compare comp);
384
385template <class ForwardIterator, class T>
386    ForwardIterator
387    lower_bound(ForwardIterator first, ForwardIterator last, const T& value);
388
389template <class ForwardIterator, class T, class Compare>
390    ForwardIterator
391    lower_bound(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
392
393template <class ForwardIterator, class T>
394    ForwardIterator
395    upper_bound(ForwardIterator first, ForwardIterator last, const T& value);
396
397template <class ForwardIterator, class T, class Compare>
398    ForwardIterator
399    upper_bound(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
400
401template <class ForwardIterator, class T>
402    pair<ForwardIterator, ForwardIterator>
403    equal_range(ForwardIterator first, ForwardIterator last, const T& value);
404
405template <class ForwardIterator, class T, class Compare>
406    pair<ForwardIterator, ForwardIterator>
407    equal_range(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
408
409template <class ForwardIterator, class T>
410    bool
411    binary_search(ForwardIterator first, ForwardIterator last, const T& value);
412
413template <class ForwardIterator, class T, class Compare>
414    bool
415    binary_search(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
416
417template <class InputIterator1, class InputIterator2, class OutputIterator>
418    OutputIterator
419    merge(InputIterator1 first1, InputIterator1 last1,
420          InputIterator2 first2, InputIterator2 last2, OutputIterator result);
421
422template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
423    OutputIterator
424    merge(InputIterator1 first1, InputIterator1 last1,
425          InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
426
427template <class BidirectionalIterator>
428    void
429    inplace_merge(BidirectionalIterator first, BidirectionalIterator middle, BidirectionalIterator last);
430
431template <class BidirectionalIterator, class Compare>
432    void
433    inplace_merge(BidirectionalIterator first, BidirectionalIterator middle, BidirectionalIterator last, Compare comp);
434
435template <class InputIterator1, class InputIterator2>
436    bool
437    includes(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2);
438
439template <class InputIterator1, class InputIterator2, class Compare>
440    bool
441    includes(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2, Compare comp);
442
443template <class InputIterator1, class InputIterator2, class OutputIterator>
444    OutputIterator
445    set_union(InputIterator1 first1, InputIterator1 last1,
446              InputIterator2 first2, InputIterator2 last2, OutputIterator result);
447
448template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
449    OutputIterator
450    set_union(InputIterator1 first1, InputIterator1 last1,
451              InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
452
453template <class InputIterator1, class InputIterator2, class OutputIterator>
454    OutputIterator
455    set_intersection(InputIterator1 first1, InputIterator1 last1,
456                     InputIterator2 first2, InputIterator2 last2, OutputIterator result);
457
458template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
459    OutputIterator
460    set_intersection(InputIterator1 first1, InputIterator1 last1,
461                     InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
462
463template <class InputIterator1, class InputIterator2, class OutputIterator>
464    OutputIterator
465    set_difference(InputIterator1 first1, InputIterator1 last1,
466                   InputIterator2 first2, InputIterator2 last2, OutputIterator result);
467
468template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
469    OutputIterator
470    set_difference(InputIterator1 first1, InputIterator1 last1,
471                   InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
472
473template <class InputIterator1, class InputIterator2, class OutputIterator>
474    OutputIterator
475    set_symmetric_difference(InputIterator1 first1, InputIterator1 last1,
476                             InputIterator2 first2, InputIterator2 last2, OutputIterator result);
477
478template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
479    OutputIterator
480    set_symmetric_difference(InputIterator1 first1, InputIterator1 last1,
481                             InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
482
483template <class RandomAccessIterator>
484    void
485    push_heap(RandomAccessIterator first, RandomAccessIterator last);
486
487template <class RandomAccessIterator, class Compare>
488    void
489    push_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
490
491template <class RandomAccessIterator>
492    void
493    pop_heap(RandomAccessIterator first, RandomAccessIterator last);
494
495template <class RandomAccessIterator, class Compare>
496    void
497    pop_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
498
499template <class RandomAccessIterator>
500    void
501    make_heap(RandomAccessIterator first, RandomAccessIterator last);
502
503template <class RandomAccessIterator, class Compare>
504    void
505    make_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
506
507template <class RandomAccessIterator>
508    void
509    sort_heap(RandomAccessIterator first, RandomAccessIterator last);
510
511template <class RandomAccessIterator, class Compare>
512    void
513    sort_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
514
515template <class RandomAccessIterator>
516    bool
517    is_heap(RandomAccessIterator first, RandomAccessiterator last);
518
519template <class RandomAccessIterator, class Compare>
520    bool
521    is_heap(RandomAccessIterator first, RandomAccessiterator last, Compare comp);
522
523template <class RandomAccessIterator>
524    RandomAccessIterator
525    is_heap_until(RandomAccessIterator first, RandomAccessiterator last);
526
527template <class RandomAccessIterator, class Compare>
528    RandomAccessIterator
529    is_heap_until(RandomAccessIterator first, RandomAccessiterator last, Compare comp);
530
531template <class ForwardIterator>
532    ForwardIterator
533    min_element(ForwardIterator first, ForwardIterator last);  // constexpr in C++14
534
535template <class ForwardIterator, class Compare>
536    ForwardIterator
537    min_element(ForwardIterator first, ForwardIterator last, Compare comp);  // constexpr in C++14
538
539template <class T>
540    const T&
541    min(const T& a, const T& b);  // constexpr in C++14
542
543template <class T, class Compare>
544    const T&
545    min(const T& a, const T& b, Compare comp);  // constexpr in C++14
546
547template<class T>
548    T
549    min(initializer_list<T> t);  // constexpr in C++14
550
551template<class T, class Compare>
552    T
553    min(initializer_list<T> t, Compare comp);  // constexpr in C++14
554
555template<class T>
556    constexpr const T& clamp( const T& v, const T& lo, const T& hi );               // C++17
557
558template<class T, class Compare>
559    constexpr const T& clamp( const T& v, const T& lo, const T& hi, Compare comp ); // C++17
560
561template <class ForwardIterator>
562    ForwardIterator
563    max_element(ForwardIterator first, ForwardIterator last);  // constexpr in C++14
564
565template <class ForwardIterator, class Compare>
566    ForwardIterator
567    max_element(ForwardIterator first, ForwardIterator last, Compare comp);  // constexpr in C++14
568
569template <class T>
570    const T&
571    max(const T& a, const T& b); // constexpr in C++14
572
573template <class T, class Compare>
574    const T&
575    max(const T& a, const T& b, Compare comp);  // constexpr in C++14
576
577template<class T>
578    T
579    max(initializer_list<T> t);  // constexpr in C++14
580
581template<class T, class Compare>
582    T
583    max(initializer_list<T> t, Compare comp);  // constexpr in C++14
584
585template<class ForwardIterator>
586    pair<ForwardIterator, ForwardIterator>
587    minmax_element(ForwardIterator first, ForwardIterator last);   // constexpr in C++14
588
589template<class ForwardIterator, class Compare>
590    pair<ForwardIterator, ForwardIterator>
591    minmax_element(ForwardIterator first, ForwardIterator last, Compare comp);   // constexpr in C++14
592
593template<class T>
594    pair<const T&, const T&>
595    minmax(const T& a, const T& b);  // constexpr in C++14
596
597template<class T, class Compare>
598    pair<const T&, const T&>
599    minmax(const T& a, const T& b, Compare comp);  // constexpr in C++14
600
601template<class T>
602    pair<T, T>
603    minmax(initializer_list<T> t);  // constexpr in C++14
604
605template<class T, class Compare>
606    pair<T, T>
607    minmax(initializer_list<T> t, Compare comp);  // constexpr in C++14
608
609template <class InputIterator1, class InputIterator2>
610    bool
611    lexicographical_compare(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2);
612
613template <class InputIterator1, class InputIterator2, class Compare>
614    bool
615    lexicographical_compare(InputIterator1 first1, InputIterator1 last1,
616                            InputIterator2 first2, InputIterator2 last2, Compare comp);
617
618template <class BidirectionalIterator>
619    bool
620    next_permutation(BidirectionalIterator first, BidirectionalIterator last);
621
622template <class BidirectionalIterator, class Compare>
623    bool
624    next_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp);
625
626template <class BidirectionalIterator>
627    bool
628    prev_permutation(BidirectionalIterator first, BidirectionalIterator last);
629
630template <class BidirectionalIterator, class Compare>
631    bool
632    prev_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp);
633
634}  // std
635
636*/
637
638#include <__config>
639#include <initializer_list>
640#include <type_traits>
641#include <cstring>
642#include <utility> // needed to provide swap_ranges.
643#include <memory>
644#include <iterator>
645#include <cstddef>
646
647#if defined(__IBMCPP__)
648#include "support/ibm/support.h"
649#endif
650#if defined(_LIBCPP_COMPILER_MSVC)
651#include <intrin.h>
652#endif
653
654#include <__debug>
655
656#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
657#pragma GCC system_header
658#endif
659
660_LIBCPP_PUSH_MACROS
661#include <__undef_macros>
662
663
664_LIBCPP_BEGIN_NAMESPACE_STD
665
666// I'd like to replace these with _VSTD::equal_to<void>, but can't because:
667//   * That only works with C++14 and later, and
668//   * We haven't included <functional> here.
669template <class _T1, class _T2 = _T1>
670struct __equal_to
671{
672    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
673    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T2& __y) const {return __x == __y;}
674    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T2& __x, const _T1& __y) const {return __x == __y;}
675    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T2& __x, const _T2& __y) const {return __x == __y;}
676};
677
678template <class _T1>
679struct __equal_to<_T1, _T1>
680{
681    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
682    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
683};
684
685template <class _T1>
686struct __equal_to<const _T1, _T1>
687{
688    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
689    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
690};
691
692template <class _T1>
693struct __equal_to<_T1, const _T1>
694{
695    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
696    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
697};
698
699template <class _T1, class _T2 = _T1>
700struct __less
701{
702    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
703    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
704
705    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
706    bool operator()(const _T1& __x, const _T2& __y) const {return __x < __y;}
707
708    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
709    bool operator()(const _T2& __x, const _T1& __y) const {return __x < __y;}
710
711    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
712    bool operator()(const _T2& __x, const _T2& __y) const {return __x < __y;}
713};
714
715template <class _T1>
716struct __less<_T1, _T1>
717{
718    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
719    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
720};
721
722template <class _T1>
723struct __less<const _T1, _T1>
724{
725    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
726    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
727};
728
729template <class _T1>
730struct __less<_T1, const _T1>
731{
732    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
733    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
734};
735
736template <class _Predicate>
737class __invert // invert the sense of a comparison
738{
739private:
740    _Predicate __p_;
741public:
742    _LIBCPP_INLINE_VISIBILITY __invert() {}
743
744    _LIBCPP_INLINE_VISIBILITY
745    explicit __invert(_Predicate __p) : __p_(__p) {}
746
747    template <class _T1>
748    _LIBCPP_INLINE_VISIBILITY
749    bool operator()(const _T1& __x) {return !__p_(__x);}
750
751    template <class _T1, class _T2>
752    _LIBCPP_INLINE_VISIBILITY
753    bool operator()(const _T1& __x, const _T2& __y) {return __p_(__y, __x);}
754};
755
756#ifdef _LIBCPP_DEBUG
757
758template <class _Compare>
759struct __debug_less
760{
761    _Compare __comp_;
762    __debug_less(_Compare& __c) : __comp_(__c) {}
763
764    template <class _Tp, class _Up>
765    bool operator()(const _Tp& __x, const _Up& __y)
766    {
767        bool __r = __comp_(__x, __y);
768        if (__r)
769            __do_compare_assert(0, __y, __x);
770        return __r;
771    }
772
773    template <class _LHS, class _RHS>
774    inline _LIBCPP_INLINE_VISIBILITY
775    decltype((void)_VSTD::declval<_Compare&>()(
776        _VSTD::declval<_LHS const&>(), _VSTD::declval<_RHS const&>()))
777    __do_compare_assert(int, _LHS const& __l, _RHS const& __r) {
778        _LIBCPP_ASSERT(!__comp_(__l, __r),
779            "Comparator does not induce a strict weak ordering");
780    }
781
782    template <class _LHS, class _RHS>
783    inline _LIBCPP_INLINE_VISIBILITY
784    void __do_compare_assert(long, _LHS const&, _RHS const&) {}
785};
786
787#endif  // _LIBCPP_DEBUG
788
789// Precondition:  __x != 0
790inline _LIBCPP_INLINE_VISIBILITY
791unsigned __ctz(unsigned __x) {
792#ifndef _LIBCPP_COMPILER_MSVC
793    return static_cast<unsigned>(__builtin_ctz(__x));
794#else
795  static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
796  static_assert(sizeof(unsigned long) == 4, "");
797  unsigned long where;
798  // Search from LSB to MSB for first set bit.
799  // Returns zero if no set bit is found.
800  if (_BitScanForward(&where, __x))
801    return where;
802  return 32;
803#endif
804}
805
806inline _LIBCPP_INLINE_VISIBILITY
807unsigned long __ctz(unsigned long __x) {
808#ifndef _LIBCPP_COMPILER_MSVC
809    return static_cast<unsigned long>(__builtin_ctzl(__x));
810#else
811    static_assert(sizeof(unsigned long) == sizeof(unsigned), "");
812    return __ctz(static_cast<unsigned>(__x));
813#endif
814}
815
816inline _LIBCPP_INLINE_VISIBILITY
817unsigned long long __ctz(unsigned long long __x) {
818#ifndef _LIBCPP_COMPILER_MSVC
819    return static_cast<unsigned long long>(__builtin_ctzll(__x));
820#else
821    unsigned long where;
822// Search from LSB to MSB for first set bit.
823// Returns zero if no set bit is found.
824#if defined(_LIBCPP_HAS_BITSCAN64)
825    (defined(_M_AMD64) || defined(__x86_64__))
826  if (_BitScanForward64(&where, __x))
827    return static_cast<int>(where);
828#else
829  // Win32 doesn't have _BitScanForward64 so emulate it with two 32 bit calls.
830  // Scan the Low Word.
831  if (_BitScanForward(&where, static_cast<unsigned long>(__x)))
832    return where;
833  // Scan the High Word.
834  if (_BitScanForward(&where, static_cast<unsigned long>(__x >> 32)))
835    return where + 32; // Create a bit offset from the LSB.
836#endif
837  return 64;
838#endif // _LIBCPP_COMPILER_MSVC
839}
840
841// Precondition:  __x != 0
842inline _LIBCPP_INLINE_VISIBILITY
843unsigned __clz(unsigned __x) {
844#ifndef _LIBCPP_COMPILER_MSVC
845    return static_cast<unsigned>(__builtin_clz(__x));
846#else
847  static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
848  static_assert(sizeof(unsigned long) == 4, "");
849  unsigned long where;
850  // Search from LSB to MSB for first set bit.
851  // Returns zero if no set bit is found.
852  if (_BitScanReverse(&where, __x))
853    return 31 - where;
854  return 32; // Undefined Behavior.
855#endif
856}
857
858inline _LIBCPP_INLINE_VISIBILITY
859unsigned long __clz(unsigned long __x) {
860#ifndef _LIBCPP_COMPILER_MSVC
861    return static_cast<unsigned long>(__builtin_clzl (__x));
862#else
863    static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
864    return __clz(static_cast<unsigned>(__x));
865#endif
866}
867
868inline _LIBCPP_INLINE_VISIBILITY
869unsigned long long __clz(unsigned long long __x) {
870#ifndef _LIBCPP_COMPILER_MSVC
871    return static_cast<unsigned long long>(__builtin_clzll(__x));
872#else
873  unsigned long where;
874// BitScanReverse scans from MSB to LSB for first set bit.
875// Returns 0 if no set bit is found.
876#if defined(_LIBCPP_HAS_BITSCAN64)
877  if (_BitScanReverse64(&where, __x))
878    return static_cast<int>(63 - where);
879#else
880  // Scan the high 32 bits.
881  if (_BitScanReverse(&where, static_cast<unsigned long>(__x >> 32)))
882    return 63 - (where + 32); // Create a bit offset from the MSB.
883  // Scan the low 32 bits.
884  if (_BitScanReverse(&where, static_cast<unsigned long>(__x)))
885    return 63 - where;
886#endif
887  return 64; // Undefined Behavior.
888#endif // _LIBCPP_COMPILER_MSVC
889}
890
891inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned __x) {
892#ifndef _LIBCPP_COMPILER_MSVC
893  return __builtin_popcount  (__x);
894#else
895  static_assert(sizeof(unsigned) == 4, "");
896  return __popcnt(__x);
897#endif
898}
899
900inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned long __x) {
901#ifndef _LIBCPP_COMPILER_MSVC
902  return __builtin_popcountl (__x);
903#else
904  static_assert(sizeof(unsigned long) == 4, "");
905  return __popcnt(__x);
906#endif
907}
908
909inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned long long __x) {
910#ifndef _LIBCPP_COMPILER_MSVC
911  return __builtin_popcountll(__x);
912#else
913  static_assert(sizeof(unsigned long long) == 8, "");
914  return __popcnt64(__x);
915#endif
916}
917
918// all_of
919
920template <class _InputIterator, class _Predicate>
921inline _LIBCPP_INLINE_VISIBILITY
922bool
923all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
924{
925    for (; __first != __last; ++__first)
926        if (!__pred(*__first))
927            return false;
928    return true;
929}
930
931// any_of
932
933template <class _InputIterator, class _Predicate>
934inline _LIBCPP_INLINE_VISIBILITY
935bool
936any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
937{
938    for (; __first != __last; ++__first)
939        if (__pred(*__first))
940            return true;
941    return false;
942}
943
944// none_of
945
946template <class _InputIterator, class _Predicate>
947inline _LIBCPP_INLINE_VISIBILITY
948bool
949none_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
950{
951    for (; __first != __last; ++__first)
952        if (__pred(*__first))
953            return false;
954    return true;
955}
956
957// for_each
958
959template <class _InputIterator, class _Function>
960inline _LIBCPP_INLINE_VISIBILITY
961_Function
962for_each(_InputIterator __first, _InputIterator __last, _Function __f)
963{
964    for (; __first != __last; ++__first)
965        __f(*__first);
966    return __f;
967}
968
969#if _LIBCPP_STD_VER > 14
970// for_each_n
971
972template <class _InputIterator, class _Size, class _Function>
973inline _LIBCPP_INLINE_VISIBILITY
974_InputIterator
975for_each_n(_InputIterator __first, _Size __orig_n, _Function __f)
976{
977    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
978    _IntegralSize __n = __orig_n;
979    while (__n > 0)
980    {
981         __f(*__first);
982         ++__first;
983         --__n;
984    }
985    return __first;
986}
987#endif
988
989// find
990
991template <class _InputIterator, class _Tp>
992inline _LIBCPP_INLINE_VISIBILITY
993_InputIterator
994find(_InputIterator __first, _InputIterator __last, const _Tp& __value_)
995{
996    for (; __first != __last; ++__first)
997        if (*__first == __value_)
998            break;
999    return __first;
1000}
1001
1002// find_if
1003
1004template <class _InputIterator, class _Predicate>
1005inline _LIBCPP_INLINE_VISIBILITY
1006_InputIterator
1007find_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
1008{
1009    for (; __first != __last; ++__first)
1010        if (__pred(*__first))
1011            break;
1012    return __first;
1013}
1014
1015// find_if_not
1016
1017template<class _InputIterator, class _Predicate>
1018inline _LIBCPP_INLINE_VISIBILITY
1019_InputIterator
1020find_if_not(_InputIterator __first, _InputIterator __last, _Predicate __pred)
1021{
1022    for (; __first != __last; ++__first)
1023        if (!__pred(*__first))
1024            break;
1025    return __first;
1026}
1027
1028// find_end
1029
1030template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
1031_ForwardIterator1
1032__find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1033           _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
1034           forward_iterator_tag, forward_iterator_tag)
1035{
1036    // modeled after search algorithm
1037    _ForwardIterator1 __r = __last1;  // __last1 is the "default" answer
1038    if (__first2 == __last2)
1039        return __r;
1040    while (true)
1041    {
1042        while (true)
1043        {
1044            if (__first1 == __last1)         // if source exhausted return last correct answer
1045                return __r;                  //    (or __last1 if never found)
1046            if (__pred(*__first1, *__first2))
1047                break;
1048            ++__first1;
1049        }
1050        // *__first1 matches *__first2, now match elements after here
1051        _ForwardIterator1 __m1 = __first1;
1052        _ForwardIterator2 __m2 = __first2;
1053        while (true)
1054        {
1055            if (++__m2 == __last2)
1056            {                         // Pattern exhaused, record answer and search for another one
1057                __r = __first1;
1058                ++__first1;
1059                break;
1060            }
1061            if (++__m1 == __last1)     // Source exhausted, return last answer
1062                return __r;
1063            if (!__pred(*__m1, *__m2))  // mismatch, restart with a new __first
1064            {
1065                ++__first1;
1066                break;
1067            }  // else there is a match, check next elements
1068        }
1069    }
1070}
1071
1072template <class _BinaryPredicate, class _BidirectionalIterator1, class _BidirectionalIterator2>
1073_BidirectionalIterator1
1074__find_end(_BidirectionalIterator1 __first1, _BidirectionalIterator1 __last1,
1075           _BidirectionalIterator2 __first2, _BidirectionalIterator2 __last2, _BinaryPredicate __pred,
1076           bidirectional_iterator_tag, bidirectional_iterator_tag)
1077{
1078    // modeled after search algorithm (in reverse)
1079    if (__first2 == __last2)
1080        return __last1;  // Everything matches an empty sequence
1081    _BidirectionalIterator1 __l1 = __last1;
1082    _BidirectionalIterator2 __l2 = __last2;
1083    --__l2;
1084    while (true)
1085    {
1086        // Find last element in sequence 1 that matchs *(__last2-1), with a mininum of loop checks
1087        while (true)
1088        {
1089            if (__first1 == __l1)  // return __last1 if no element matches *__first2
1090                return __last1;
1091            if (__pred(*--__l1, *__l2))
1092                break;
1093        }
1094        // *__l1 matches *__l2, now match elements before here
1095        _BidirectionalIterator1 __m1 = __l1;
1096        _BidirectionalIterator2 __m2 = __l2;
1097        while (true)
1098        {
1099            if (__m2 == __first2)  // If pattern exhausted, __m1 is the answer (works for 1 element pattern)
1100                return __m1;
1101            if (__m1 == __first1)  // Otherwise if source exhaused, pattern not found
1102                return __last1;
1103            if (!__pred(*--__m1, *--__m2))  // if there is a mismatch, restart with a new __l1
1104            {
1105                break;
1106            }  // else there is a match, check next elements
1107        }
1108    }
1109}
1110
1111template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1112_LIBCPP_CONSTEXPR_AFTER_CXX11 _RandomAccessIterator1
1113__find_end(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
1114           _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
1115           random_access_iterator_tag, random_access_iterator_tag)
1116{
1117    // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
1118    typename iterator_traits<_RandomAccessIterator2>::difference_type __len2 = __last2 - __first2;
1119    if (__len2 == 0)
1120        return __last1;
1121    typename iterator_traits<_RandomAccessIterator1>::difference_type __len1 = __last1 - __first1;
1122    if (__len1 < __len2)
1123        return __last1;
1124    const _RandomAccessIterator1 __s = __first1 + (__len2 - 1);  // End of pattern match can't go before here
1125    _RandomAccessIterator1 __l1 = __last1;
1126    _RandomAccessIterator2 __l2 = __last2;
1127    --__l2;
1128    while (true)
1129    {
1130        while (true)
1131        {
1132            if (__s == __l1)
1133                return __last1;
1134            if (__pred(*--__l1, *__l2))
1135                break;
1136        }
1137        _RandomAccessIterator1 __m1 = __l1;
1138        _RandomAccessIterator2 __m2 = __l2;
1139        while (true)
1140        {
1141            if (__m2 == __first2)
1142                return __m1;
1143                                 // no need to check range on __m1 because __s guarantees we have enough source
1144            if (!__pred(*--__m1, *--__m2))
1145            {
1146                break;
1147            }
1148        }
1149    }
1150}
1151
1152template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1153inline _LIBCPP_INLINE_VISIBILITY
1154_ForwardIterator1
1155find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1156         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1157{
1158    return _VSTD::__find_end<typename add_lvalue_reference<_BinaryPredicate>::type>
1159                         (__first1, __last1, __first2, __last2, __pred,
1160                          typename iterator_traits<_ForwardIterator1>::iterator_category(),
1161                          typename iterator_traits<_ForwardIterator2>::iterator_category());
1162}
1163
1164template <class _ForwardIterator1, class _ForwardIterator2>
1165inline _LIBCPP_INLINE_VISIBILITY
1166_ForwardIterator1
1167find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1168         _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1169{
1170    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1171    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1172    return _VSTD::find_end(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1173}
1174
1175// find_first_of
1176
1177template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1178_LIBCPP_CONSTEXPR_AFTER_CXX11 _ForwardIterator1
1179__find_first_of_ce(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1180              _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1181{
1182    for (; __first1 != __last1; ++__first1)
1183        for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
1184            if (__pred(*__first1, *__j))
1185                return __first1;
1186    return __last1;
1187}
1188
1189
1190template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1191inline _LIBCPP_INLINE_VISIBILITY
1192_ForwardIterator1
1193find_first_of(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1194              _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1195{
1196    return _VSTD::__find_first_of_ce(__first1, __last1, __first2, __last2, __pred);
1197}
1198
1199template <class _ForwardIterator1, class _ForwardIterator2>
1200inline _LIBCPP_INLINE_VISIBILITY
1201_ForwardIterator1
1202find_first_of(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1203              _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1204{
1205    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1206    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1207    return _VSTD::__find_first_of_ce(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1208}
1209
1210// adjacent_find
1211
1212template <class _ForwardIterator, class _BinaryPredicate>
1213inline _LIBCPP_INLINE_VISIBILITY
1214_ForwardIterator
1215adjacent_find(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
1216{
1217    if (__first != __last)
1218    {
1219        _ForwardIterator __i = __first;
1220        while (++__i != __last)
1221        {
1222            if (__pred(*__first, *__i))
1223                return __first;
1224            __first = __i;
1225        }
1226    }
1227    return __last;
1228}
1229
1230template <class _ForwardIterator>
1231inline _LIBCPP_INLINE_VISIBILITY
1232_ForwardIterator
1233adjacent_find(_ForwardIterator __first, _ForwardIterator __last)
1234{
1235    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
1236    return _VSTD::adjacent_find(__first, __last, __equal_to<__v>());
1237}
1238
1239// count
1240
1241template <class _InputIterator, class _Tp>
1242inline _LIBCPP_INLINE_VISIBILITY
1243typename iterator_traits<_InputIterator>::difference_type
1244count(_InputIterator __first, _InputIterator __last, const _Tp& __value_)
1245{
1246    typename iterator_traits<_InputIterator>::difference_type __r(0);
1247    for (; __first != __last; ++__first)
1248        if (*__first == __value_)
1249            ++__r;
1250    return __r;
1251}
1252
1253// count_if
1254
1255template <class _InputIterator, class _Predicate>
1256inline _LIBCPP_INLINE_VISIBILITY
1257typename iterator_traits<_InputIterator>::difference_type
1258count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
1259{
1260    typename iterator_traits<_InputIterator>::difference_type __r(0);
1261    for (; __first != __last; ++__first)
1262        if (__pred(*__first))
1263            ++__r;
1264    return __r;
1265}
1266
1267// mismatch
1268
1269template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1270inline _LIBCPP_INLINE_VISIBILITY
1271pair<_InputIterator1, _InputIterator2>
1272mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1273         _InputIterator2 __first2, _BinaryPredicate __pred)
1274{
1275    for (; __first1 != __last1; ++__first1, (void) ++__first2)
1276        if (!__pred(*__first1, *__first2))
1277            break;
1278    return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1279}
1280
1281template <class _InputIterator1, class _InputIterator2>
1282inline _LIBCPP_INLINE_VISIBILITY
1283pair<_InputIterator1, _InputIterator2>
1284mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2)
1285{
1286    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1287    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1288    return _VSTD::mismatch(__first1, __last1, __first2, __equal_to<__v1, __v2>());
1289}
1290
1291#if _LIBCPP_STD_VER > 11
1292template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1293inline _LIBCPP_INLINE_VISIBILITY
1294pair<_InputIterator1, _InputIterator2>
1295mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1296         _InputIterator2 __first2, _InputIterator2 __last2,
1297         _BinaryPredicate __pred)
1298{
1299    for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void) ++__first2)
1300        if (!__pred(*__first1, *__first2))
1301            break;
1302    return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1303}
1304
1305template <class _InputIterator1, class _InputIterator2>
1306inline _LIBCPP_INLINE_VISIBILITY
1307pair<_InputIterator1, _InputIterator2>
1308mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1309         _InputIterator2 __first2, _InputIterator2 __last2)
1310{
1311    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1312    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1313    return _VSTD::mismatch(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1314}
1315#endif
1316
1317// equal
1318
1319template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1320inline _LIBCPP_INLINE_VISIBILITY
1321bool
1322equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate __pred)
1323{
1324    for (; __first1 != __last1; ++__first1, (void) ++__first2)
1325        if (!__pred(*__first1, *__first2))
1326            return false;
1327    return true;
1328}
1329
1330template <class _InputIterator1, class _InputIterator2>
1331inline _LIBCPP_INLINE_VISIBILITY
1332bool
1333equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2)
1334{
1335    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1336    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1337    return _VSTD::equal(__first1, __last1, __first2, __equal_to<__v1, __v2>());
1338}
1339
1340#if _LIBCPP_STD_VER > 11
1341template <class _BinaryPredicate, class _InputIterator1, class _InputIterator2>
1342inline _LIBCPP_INLINE_VISIBILITY
1343bool
1344__equal(_InputIterator1 __first1, _InputIterator1 __last1,
1345        _InputIterator2 __first2, _InputIterator2 __last2, _BinaryPredicate __pred,
1346        input_iterator_tag, input_iterator_tag )
1347{
1348    for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void) ++__first2)
1349        if (!__pred(*__first1, *__first2))
1350            return false;
1351    return __first1 == __last1 && __first2 == __last2;
1352}
1353
1354template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1355inline _LIBCPP_INLINE_VISIBILITY
1356bool
1357__equal(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
1358        _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
1359      random_access_iterator_tag, random_access_iterator_tag )
1360{
1361    if ( _VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
1362        return false;
1363    return _VSTD::equal<_RandomAccessIterator1, _RandomAccessIterator2,
1364                        typename add_lvalue_reference<_BinaryPredicate>::type>
1365                       (__first1, __last1, __first2, __pred );
1366}
1367
1368template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1369inline _LIBCPP_INLINE_VISIBILITY
1370bool
1371equal(_InputIterator1 __first1, _InputIterator1 __last1,
1372      _InputIterator2 __first2, _InputIterator2 __last2, _BinaryPredicate __pred )
1373{
1374    return _VSTD::__equal<typename add_lvalue_reference<_BinaryPredicate>::type>
1375       (__first1, __last1, __first2, __last2, __pred,
1376        typename iterator_traits<_InputIterator1>::iterator_category(),
1377        typename iterator_traits<_InputIterator2>::iterator_category());
1378}
1379
1380template <class _InputIterator1, class _InputIterator2>
1381inline _LIBCPP_INLINE_VISIBILITY
1382bool
1383equal(_InputIterator1 __first1, _InputIterator1 __last1,
1384      _InputIterator2 __first2, _InputIterator2 __last2)
1385{
1386    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1387    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1388    return _VSTD::__equal(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>(),
1389        typename iterator_traits<_InputIterator1>::iterator_category(),
1390        typename iterator_traits<_InputIterator2>::iterator_category());
1391}
1392#endif
1393
1394// is_permutation
1395
1396template<class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1397bool
1398is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1399               _ForwardIterator2 __first2, _BinaryPredicate __pred)
1400{
1401    // shorten sequences as much as possible by lopping of any equal parts
1402    for (; __first1 != __last1; ++__first1, (void) ++__first2)
1403        if (!__pred(*__first1, *__first2))
1404            goto __not_done;
1405    return true;
1406__not_done:
1407    // __first1 != __last1 && *__first1 != *__first2
1408    typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
1409    _D1 __l1 = _VSTD::distance(__first1, __last1);
1410    if (__l1 == _D1(1))
1411        return false;
1412    _ForwardIterator2 __last2 = _VSTD::next(__first2, __l1);
1413    // For each element in [f1, l1) see if there are the same number of
1414    //    equal elements in [f2, l2)
1415    for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i)
1416    {
1417        // Have we already counted the number of *__i in [f1, l1)?
1418        for (_ForwardIterator1 __j = __first1; __j != __i; ++__j)
1419            if (__pred(*__j, *__i))
1420                goto __next_iter;
1421        {
1422            // Count number of *__i in [f2, l2)
1423            _D1 __c2 = 0;
1424            for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
1425                if (__pred(*__i, *__j))
1426                    ++__c2;
1427            if (__c2 == 0)
1428                return false;
1429            // Count number of *__i in [__i, l1) (we can start with 1)
1430            _D1 __c1 = 1;
1431            for (_ForwardIterator1 __j = _VSTD::next(__i); __j != __last1; ++__j)
1432                if (__pred(*__i, *__j))
1433                    ++__c1;
1434            if (__c1 != __c2)
1435                return false;
1436        }
1437__next_iter:;
1438    }
1439    return true;
1440}
1441
1442template<class _ForwardIterator1, class _ForwardIterator2>
1443inline _LIBCPP_INLINE_VISIBILITY
1444bool
1445is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1446               _ForwardIterator2 __first2)
1447{
1448    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1449    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1450    return _VSTD::is_permutation(__first1, __last1, __first2, __equal_to<__v1, __v2>());
1451}
1452
1453#if _LIBCPP_STD_VER > 11
1454template<class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
1455bool
1456__is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1457                 _ForwardIterator2 __first2, _ForwardIterator2 __last2,
1458                 _BinaryPredicate __pred,
1459                 forward_iterator_tag, forward_iterator_tag )
1460{
1461    // shorten sequences as much as possible by lopping of any equal parts
1462    for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void) ++__first2)
1463        if (!__pred(*__first1, *__first2))
1464            goto __not_done;
1465    return __first1 == __last1 && __first2 == __last2;
1466__not_done:
1467    // __first1 != __last1 && __first2 != __last2 && *__first1 != *__first2
1468    typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
1469    _D1 __l1 = _VSTD::distance(__first1, __last1);
1470
1471    typedef typename iterator_traits<_ForwardIterator2>::difference_type _D2;
1472    _D2 __l2 = _VSTD::distance(__first2, __last2);
1473    if (__l1 != __l2)
1474        return false;
1475
1476    // For each element in [f1, l1) see if there are the same number of
1477    //    equal elements in [f2, l2)
1478    for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i)
1479    {
1480        // Have we already counted the number of *__i in [f1, l1)?
1481        for (_ForwardIterator1 __j = __first1; __j != __i; ++__j)
1482            if (__pred(*__j, *__i))
1483                goto __next_iter;
1484        {
1485            // Count number of *__i in [f2, l2)
1486            _D1 __c2 = 0;
1487            for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
1488                if (__pred(*__i, *__j))
1489                    ++__c2;
1490            if (__c2 == 0)
1491                return false;
1492            // Count number of *__i in [__i, l1) (we can start with 1)
1493            _D1 __c1 = 1;
1494            for (_ForwardIterator1 __j = _VSTD::next(__i); __j != __last1; ++__j)
1495                if (__pred(*__i, *__j))
1496                    ++__c1;
1497            if (__c1 != __c2)
1498                return false;
1499        }
1500__next_iter:;
1501    }
1502    return true;
1503}
1504
1505template<class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1506bool
1507__is_permutation(_RandomAccessIterator1 __first1, _RandomAccessIterator2 __last1,
1508               _RandomAccessIterator1 __first2, _RandomAccessIterator2 __last2,
1509               _BinaryPredicate __pred,
1510               random_access_iterator_tag, random_access_iterator_tag )
1511{
1512    if ( _VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
1513        return false;
1514    return _VSTD::is_permutation<_RandomAccessIterator1, _RandomAccessIterator2,
1515                                 typename add_lvalue_reference<_BinaryPredicate>::type>
1516                                (__first1, __last1, __first2, __pred );
1517}
1518
1519template<class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1520inline _LIBCPP_INLINE_VISIBILITY
1521bool
1522is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1523               _ForwardIterator2 __first2, _ForwardIterator2 __last2,
1524               _BinaryPredicate __pred )
1525{
1526    return _VSTD::__is_permutation<typename add_lvalue_reference<_BinaryPredicate>::type>
1527       (__first1, __last1, __first2, __last2, __pred,
1528        typename iterator_traits<_ForwardIterator1>::iterator_category(),
1529        typename iterator_traits<_ForwardIterator2>::iterator_category());
1530}
1531
1532template<class _ForwardIterator1, class _ForwardIterator2>
1533inline _LIBCPP_INLINE_VISIBILITY
1534bool
1535is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1536               _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1537{
1538    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1539    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1540    return _VSTD::__is_permutation(__first1, __last1, __first2, __last2,
1541        __equal_to<__v1, __v2>(),
1542        typename iterator_traits<_ForwardIterator1>::iterator_category(),
1543        typename iterator_traits<_ForwardIterator2>::iterator_category());
1544}
1545#endif
1546
1547// search
1548
1549template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
1550pair<_ForwardIterator1, _ForwardIterator1>
1551__search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1552         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
1553         forward_iterator_tag, forward_iterator_tag)
1554{
1555    if (__first2 == __last2)
1556        return make_pair(__first1, __first1);  // Everything matches an empty sequence
1557    while (true)
1558    {
1559        // Find first element in sequence 1 that matchs *__first2, with a mininum of loop checks
1560        while (true)
1561        {
1562            if (__first1 == __last1)  // return __last1 if no element matches *__first2
1563                return make_pair(__last1, __last1);
1564            if (__pred(*__first1, *__first2))
1565                break;
1566            ++__first1;
1567        }
1568        // *__first1 matches *__first2, now match elements after here
1569        _ForwardIterator1 __m1 = __first1;
1570        _ForwardIterator2 __m2 = __first2;
1571        while (true)
1572        {
1573            if (++__m2 == __last2)  // If pattern exhausted, __first1 is the answer (works for 1 element pattern)
1574                return make_pair(__first1, __m1);
1575            if (++__m1 == __last1)  // Otherwise if source exhaused, pattern not found
1576                return make_pair(__last1, __last1);
1577            if (!__pred(*__m1, *__m2))  // if there is a mismatch, restart with a new __first1
1578            {
1579                ++__first1;
1580                break;
1581            }  // else there is a match, check next elements
1582        }
1583    }
1584}
1585
1586template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1587_LIBCPP_CONSTEXPR_AFTER_CXX11
1588pair<_RandomAccessIterator1, _RandomAccessIterator1>
1589__search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
1590         _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
1591           random_access_iterator_tag, random_access_iterator_tag)
1592{
1593    typedef typename iterator_traits<_RandomAccessIterator1>::difference_type _D1;
1594    typedef typename iterator_traits<_RandomAccessIterator2>::difference_type _D2;
1595    // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
1596    const _D2 __len2 = __last2 - __first2;
1597    if (__len2 == 0)
1598        return make_pair(__first1, __first1);
1599    const _D1 __len1 = __last1 - __first1;
1600    if (__len1 < __len2)
1601        return make_pair(__last1, __last1);
1602    const _RandomAccessIterator1 __s = __last1 - (__len2 - 1);  // Start of pattern match can't go beyond here
1603
1604    while (true)
1605    {
1606        while (true)
1607        {
1608            if (__first1 == __s)
1609                return make_pair(__last1, __last1);
1610            if (__pred(*__first1, *__first2))
1611                break;
1612            ++__first1;
1613        }
1614
1615        _RandomAccessIterator1 __m1 = __first1;
1616        _RandomAccessIterator2 __m2 = __first2;
1617         while (true)
1618         {
1619             if (++__m2 == __last2)
1620                 return make_pair(__first1, __first1 + __len2);
1621             ++__m1;          // no need to check range on __m1 because __s guarantees we have enough source
1622             if (!__pred(*__m1, *__m2))
1623             {
1624                 ++__first1;
1625                 break;
1626             }
1627         }
1628    }
1629}
1630
1631template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1632inline _LIBCPP_INLINE_VISIBILITY
1633_ForwardIterator1
1634search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1635       _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1636{
1637    return _VSTD::__search<typename add_lvalue_reference<_BinaryPredicate>::type>
1638                         (__first1, __last1, __first2, __last2, __pred,
1639                          typename iterator_traits<_ForwardIterator1>::iterator_category(),
1640                          typename iterator_traits<_ForwardIterator2>::iterator_category())
1641            .first;
1642}
1643
1644template <class _ForwardIterator1, class _ForwardIterator2>
1645inline _LIBCPP_INLINE_VISIBILITY
1646_ForwardIterator1
1647search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1648       _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1649{
1650    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1651    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1652    return _VSTD::search(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1653}
1654
1655// search_n
1656
1657template <class _BinaryPredicate, class _ForwardIterator, class _Size, class _Tp>
1658_ForwardIterator
1659__search_n(_ForwardIterator __first, _ForwardIterator __last,
1660           _Size __count, const _Tp& __value_, _BinaryPredicate __pred, forward_iterator_tag)
1661{
1662    if (__count <= 0)
1663        return __first;
1664    while (true)
1665    {
1666        // Find first element in sequence that matchs __value_, with a mininum of loop checks
1667        while (true)
1668        {
1669            if (__first == __last)  // return __last if no element matches __value_
1670                return __last;
1671            if (__pred(*__first, __value_))
1672                break;
1673            ++__first;
1674        }
1675        // *__first matches __value_, now match elements after here
1676        _ForwardIterator __m = __first;
1677        _Size __c(0);
1678        while (true)
1679        {
1680            if (++__c == __count)  // If pattern exhausted, __first is the answer (works for 1 element pattern)
1681                return __first;
1682            if (++__m == __last)  // Otherwise if source exhaused, pattern not found
1683                return __last;
1684            if (!__pred(*__m, __value_))  // if there is a mismatch, restart with a new __first
1685            {
1686                __first = __m;
1687                ++__first;
1688                break;
1689            }  // else there is a match, check next elements
1690        }
1691    }
1692}
1693
1694template <class _BinaryPredicate, class _RandomAccessIterator, class _Size, class _Tp>
1695_RandomAccessIterator
1696__search_n(_RandomAccessIterator __first, _RandomAccessIterator __last,
1697           _Size __count, const _Tp& __value_, _BinaryPredicate __pred, random_access_iterator_tag)
1698{
1699    if (__count <= 0)
1700        return __first;
1701    _Size __len = static_cast<_Size>(__last - __first);
1702    if (__len < __count)
1703        return __last;
1704    const _RandomAccessIterator __s = __last - (__count - 1);  // Start of pattern match can't go beyond here
1705    while (true)
1706    {
1707        // Find first element in sequence that matchs __value_, with a mininum of loop checks
1708        while (true)
1709        {
1710            if (__first >= __s)  // return __last if no element matches __value_
1711                return __last;
1712            if (__pred(*__first, __value_))
1713                break;
1714            ++__first;
1715        }
1716        // *__first matches __value_, now match elements after here
1717        _RandomAccessIterator __m = __first;
1718        _Size __c(0);
1719        while (true)
1720        {
1721            if (++__c == __count)  // If pattern exhausted, __first is the answer (works for 1 element pattern)
1722                return __first;
1723             ++__m;          // no need to check range on __m because __s guarantees we have enough source
1724            if (!__pred(*__m, __value_))  // if there is a mismatch, restart with a new __first
1725            {
1726                __first = __m;
1727                ++__first;
1728                break;
1729            }  // else there is a match, check next elements
1730        }
1731    }
1732}
1733
1734template <class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
1735inline _LIBCPP_INLINE_VISIBILITY
1736_ForwardIterator
1737search_n(_ForwardIterator __first, _ForwardIterator __last,
1738         _Size __count, const _Tp& __value_, _BinaryPredicate __pred)
1739{
1740    return _VSTD::__search_n<typename add_lvalue_reference<_BinaryPredicate>::type>
1741           (__first, __last, __convert_to_integral(__count), __value_, __pred,
1742           typename iterator_traits<_ForwardIterator>::iterator_category());
1743}
1744
1745template <class _ForwardIterator, class _Size, class _Tp>
1746inline _LIBCPP_INLINE_VISIBILITY
1747_ForwardIterator
1748search_n(_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value_)
1749{
1750    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
1751    return _VSTD::search_n(__first, __last, __convert_to_integral(__count),
1752                           __value_, __equal_to<__v, _Tp>());
1753}
1754
1755// copy
1756template <class _Iter>
1757inline _LIBCPP_INLINE_VISIBILITY
1758_Iter
1759__unwrap_iter(_Iter __i)
1760{
1761    return __i;
1762}
1763
1764template <class _Tp>
1765inline _LIBCPP_INLINE_VISIBILITY
1766typename enable_if
1767<
1768    is_trivially_copy_assignable<_Tp>::value,
1769    _Tp*
1770>::type
1771__unwrap_iter(move_iterator<_Tp*> __i)
1772{
1773    return __i.base();
1774}
1775
1776#if _LIBCPP_DEBUG_LEVEL < 2
1777
1778template <class _Tp>
1779inline _LIBCPP_INLINE_VISIBILITY
1780typename enable_if
1781<
1782    is_trivially_copy_assignable<_Tp>::value,
1783    _Tp*
1784>::type
1785__unwrap_iter(__wrap_iter<_Tp*> __i)
1786{
1787    return __i.base();
1788}
1789
1790#else
1791
1792template <class _Tp>
1793inline _LIBCPP_INLINE_VISIBILITY
1794typename enable_if
1795<
1796    is_trivially_copy_assignable<_Tp>::value,
1797    __wrap_iter<_Tp*>
1798>::type
1799__unwrap_iter(__wrap_iter<_Tp*> __i)
1800{
1801    return __i;
1802}
1803
1804#endif  // _LIBCPP_DEBUG_LEVEL < 2
1805
1806template <class _InputIterator, class _OutputIterator>
1807inline _LIBCPP_INLINE_VISIBILITY
1808_OutputIterator
1809__copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1810{
1811    for (; __first != __last; ++__first, (void) ++__result)
1812        *__result = *__first;
1813    return __result;
1814}
1815
1816template <class _Tp, class _Up>
1817inline _LIBCPP_INLINE_VISIBILITY
1818typename enable_if
1819<
1820    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1821    is_trivially_copy_assignable<_Up>::value,
1822    _Up*
1823>::type
1824__copy(_Tp* __first, _Tp* __last, _Up* __result)
1825{
1826    const size_t __n = static_cast<size_t>(__last - __first);
1827    if (__n > 0)
1828        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1829    return __result + __n;
1830}
1831
1832template <class _InputIterator, class _OutputIterator>
1833inline _LIBCPP_INLINE_VISIBILITY
1834_OutputIterator
1835copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1836{
1837    return _VSTD::__copy(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
1838}
1839
1840// copy_backward
1841
1842template <class _BidirectionalIterator, class _OutputIterator>
1843inline _LIBCPP_INLINE_VISIBILITY
1844_OutputIterator
1845__copy_backward(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
1846{
1847    while (__first != __last)
1848        *--__result = *--__last;
1849    return __result;
1850}
1851
1852template <class _Tp, class _Up>
1853inline _LIBCPP_INLINE_VISIBILITY
1854typename enable_if
1855<
1856    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1857    is_trivially_copy_assignable<_Up>::value,
1858    _Up*
1859>::type
1860__copy_backward(_Tp* __first, _Tp* __last, _Up* __result)
1861{
1862    const size_t __n = static_cast<size_t>(__last - __first);
1863    if (__n > 0)
1864    {
1865        __result -= __n;
1866        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1867    }
1868    return __result;
1869}
1870
1871template <class _BidirectionalIterator1, class _BidirectionalIterator2>
1872inline _LIBCPP_INLINE_VISIBILITY
1873_BidirectionalIterator2
1874copy_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
1875              _BidirectionalIterator2 __result)
1876{
1877    return _VSTD::__copy_backward(__unwrap_iter(__first),
1878                                  __unwrap_iter(__last),
1879                                  __unwrap_iter(__result));
1880}
1881
1882// copy_if
1883
1884template<class _InputIterator, class _OutputIterator, class _Predicate>
1885inline _LIBCPP_INLINE_VISIBILITY
1886_OutputIterator
1887copy_if(_InputIterator __first, _InputIterator __last,
1888        _OutputIterator __result, _Predicate __pred)
1889{
1890    for (; __first != __last; ++__first)
1891    {
1892        if (__pred(*__first))
1893        {
1894            *__result = *__first;
1895            ++__result;
1896        }
1897    }
1898    return __result;
1899}
1900
1901// copy_n
1902
1903template<class _InputIterator, class _Size, class _OutputIterator>
1904inline _LIBCPP_INLINE_VISIBILITY
1905typename enable_if
1906<
1907    __is_input_iterator<_InputIterator>::value &&
1908   !__is_random_access_iterator<_InputIterator>::value,
1909    _OutputIterator
1910>::type
1911copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
1912{
1913    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
1914    _IntegralSize __n = __orig_n;
1915    if (__n > 0)
1916    {
1917        *__result = *__first;
1918        ++__result;
1919        for (--__n; __n > 0; --__n)
1920        {
1921            ++__first;
1922            *__result = *__first;
1923            ++__result;
1924        }
1925    }
1926    return __result;
1927}
1928
1929template<class _InputIterator, class _Size, class _OutputIterator>
1930inline _LIBCPP_INLINE_VISIBILITY
1931typename enable_if
1932<
1933    __is_random_access_iterator<_InputIterator>::value,
1934    _OutputIterator
1935>::type
1936copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
1937{
1938    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
1939    _IntegralSize __n = __orig_n;
1940    return _VSTD::copy(__first, __first + __n, __result);
1941}
1942
1943// move
1944
1945template <class _InputIterator, class _OutputIterator>
1946inline _LIBCPP_INLINE_VISIBILITY
1947_OutputIterator
1948__move(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1949{
1950    for (; __first != __last; ++__first, (void) ++__result)
1951        *__result = _VSTD::move(*__first);
1952    return __result;
1953}
1954
1955template <class _Tp, class _Up>
1956inline _LIBCPP_INLINE_VISIBILITY
1957typename enable_if
1958<
1959    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1960    is_trivially_copy_assignable<_Up>::value,
1961    _Up*
1962>::type
1963__move(_Tp* __first, _Tp* __last, _Up* __result)
1964{
1965    const size_t __n = static_cast<size_t>(__last - __first);
1966    if (__n > 0)
1967        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1968    return __result + __n;
1969}
1970
1971template <class _InputIterator, class _OutputIterator>
1972inline _LIBCPP_INLINE_VISIBILITY
1973_OutputIterator
1974move(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1975{
1976    return _VSTD::__move(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
1977}
1978
1979// move_backward
1980
1981template <class _InputIterator, class _OutputIterator>
1982inline _LIBCPP_INLINE_VISIBILITY
1983_OutputIterator
1984__move_backward(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1985{
1986    while (__first != __last)
1987        *--__result = _VSTD::move(*--__last);
1988    return __result;
1989}
1990
1991template <class _Tp, class _Up>
1992inline _LIBCPP_INLINE_VISIBILITY
1993typename enable_if
1994<
1995    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1996    is_trivially_copy_assignable<_Up>::value,
1997    _Up*
1998>::type
1999__move_backward(_Tp* __first, _Tp* __last, _Up* __result)
2000{
2001    const size_t __n = static_cast<size_t>(__last - __first);
2002    if (__n > 0)
2003    {
2004        __result -= __n;
2005        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
2006    }
2007    return __result;
2008}
2009
2010template <class _BidirectionalIterator1, class _BidirectionalIterator2>
2011inline _LIBCPP_INLINE_VISIBILITY
2012_BidirectionalIterator2
2013move_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
2014              _BidirectionalIterator2 __result)
2015{
2016    return _VSTD::__move_backward(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
2017}
2018
2019// iter_swap
2020
2021// moved to <type_traits> for better swap / noexcept support
2022
2023// transform
2024
2025template <class _InputIterator, class _OutputIterator, class _UnaryOperation>
2026inline _LIBCPP_INLINE_VISIBILITY
2027_OutputIterator
2028transform(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _UnaryOperation __op)
2029{
2030    for (; __first != __last; ++__first, (void) ++__result)
2031        *__result = __op(*__first);
2032    return __result;
2033}
2034
2035template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _BinaryOperation>
2036inline _LIBCPP_INLINE_VISIBILITY
2037_OutputIterator
2038transform(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2,
2039          _OutputIterator __result, _BinaryOperation __binary_op)
2040{
2041    for (; __first1 != __last1; ++__first1, (void) ++__first2, ++__result)
2042        *__result = __binary_op(*__first1, *__first2);
2043    return __result;
2044}
2045
2046// replace
2047
2048template <class _ForwardIterator, class _Tp>
2049inline _LIBCPP_INLINE_VISIBILITY
2050void
2051replace(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __old_value, const _Tp& __new_value)
2052{
2053    for (; __first != __last; ++__first)
2054        if (*__first == __old_value)
2055            *__first = __new_value;
2056}
2057
2058// replace_if
2059
2060template <class _ForwardIterator, class _Predicate, class _Tp>
2061inline _LIBCPP_INLINE_VISIBILITY
2062void
2063replace_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, const _Tp& __new_value)
2064{
2065    for (; __first != __last; ++__first)
2066        if (__pred(*__first))
2067            *__first = __new_value;
2068}
2069
2070// replace_copy
2071
2072template <class _InputIterator, class _OutputIterator, class _Tp>
2073inline _LIBCPP_INLINE_VISIBILITY
2074_OutputIterator
2075replace_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
2076             const _Tp& __old_value, const _Tp& __new_value)
2077{
2078    for (; __first != __last; ++__first, (void) ++__result)
2079        if (*__first == __old_value)
2080            *__result = __new_value;
2081        else
2082            *__result = *__first;
2083    return __result;
2084}
2085
2086// replace_copy_if
2087
2088template <class _InputIterator, class _OutputIterator, class _Predicate, class _Tp>
2089inline _LIBCPP_INLINE_VISIBILITY
2090_OutputIterator
2091replace_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
2092                _Predicate __pred, const _Tp& __new_value)
2093{
2094    for (; __first != __last; ++__first, (void) ++__result)
2095        if (__pred(*__first))
2096            *__result = __new_value;
2097        else
2098            *__result = *__first;
2099    return __result;
2100}
2101
2102// fill_n
2103
2104template <class _OutputIterator, class _Size, class _Tp>
2105inline _LIBCPP_INLINE_VISIBILITY
2106_OutputIterator
2107__fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
2108{
2109    for (; __n > 0; ++__first, (void) --__n)
2110        *__first = __value_;
2111    return __first;
2112}
2113
2114template <class _Tp, class _Size, class _Up>
2115inline _LIBCPP_INLINE_VISIBILITY
2116typename enable_if
2117<
2118    is_integral<_Tp>::value && sizeof(_Tp) == 1 &&
2119    !is_same<_Tp, bool>::value &&
2120    is_integral<_Up>::value && sizeof(_Up) == 1,
2121    _Tp*
2122>::type
2123__fill_n(_Tp* __first, _Size __n,_Up __value_)
2124{
2125    if (__n > 0)
2126        _VSTD::memset(__first, (unsigned char)__value_, (size_t)(__n));
2127    return __first + __n;
2128}
2129
2130template <class _OutputIterator, class _Size, class _Tp>
2131inline _LIBCPP_INLINE_VISIBILITY
2132_OutputIterator
2133fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
2134{
2135   return _VSTD::__fill_n(__first, __convert_to_integral(__n), __value_);
2136}
2137
2138// fill
2139
2140template <class _ForwardIterator, class _Tp>
2141inline _LIBCPP_INLINE_VISIBILITY
2142void
2143__fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, forward_iterator_tag)
2144{
2145    for (; __first != __last; ++__first)
2146        *__first = __value_;
2147}
2148
2149template <class _RandomAccessIterator, class _Tp>
2150inline _LIBCPP_INLINE_VISIBILITY
2151void
2152__fill(_RandomAccessIterator __first, _RandomAccessIterator __last, const _Tp& __value_, random_access_iterator_tag)
2153{
2154    _VSTD::fill_n(__first, __last - __first, __value_);
2155}
2156
2157template <class _ForwardIterator, class _Tp>
2158inline _LIBCPP_INLINE_VISIBILITY
2159void
2160fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
2161{
2162    _VSTD::__fill(__first, __last, __value_, typename iterator_traits<_ForwardIterator>::iterator_category());
2163}
2164
2165// generate
2166
2167template <class _ForwardIterator, class _Generator>
2168inline _LIBCPP_INLINE_VISIBILITY
2169void
2170generate(_ForwardIterator __first, _ForwardIterator __last, _Generator __gen)
2171{
2172    for (; __first != __last; ++__first)
2173        *__first = __gen();
2174}
2175
2176// generate_n
2177
2178template <class _OutputIterator, class _Size, class _Generator>
2179inline _LIBCPP_INLINE_VISIBILITY
2180_OutputIterator
2181generate_n(_OutputIterator __first, _Size __orig_n, _Generator __gen)
2182{
2183    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
2184    _IntegralSize __n = __orig_n;
2185    for (; __n > 0; ++__first, (void) --__n)
2186        *__first = __gen();
2187    return __first;
2188}
2189
2190// remove
2191
2192template <class _ForwardIterator, class _Tp>
2193_ForwardIterator
2194remove(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
2195{
2196    __first = _VSTD::find(__first, __last, __value_);
2197    if (__first != __last)
2198    {
2199        _ForwardIterator __i = __first;
2200        while (++__i != __last)
2201        {
2202            if (!(*__i == __value_))
2203            {
2204                *__first = _VSTD::move(*__i);
2205                ++__first;
2206            }
2207        }
2208    }
2209    return __first;
2210}
2211
2212// remove_if
2213
2214template <class _ForwardIterator, class _Predicate>
2215_ForwardIterator
2216remove_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
2217{
2218    __first = _VSTD::find_if<_ForwardIterator, typename add_lvalue_reference<_Predicate>::type>
2219                           (__first, __last, __pred);
2220    if (__first != __last)
2221    {
2222        _ForwardIterator __i = __first;
2223        while (++__i != __last)
2224        {
2225            if (!__pred(*__i))
2226            {
2227                *__first = _VSTD::move(*__i);
2228                ++__first;
2229            }
2230        }
2231    }
2232    return __first;
2233}
2234
2235// remove_copy
2236
2237template <class _InputIterator, class _OutputIterator, class _Tp>
2238inline _LIBCPP_INLINE_VISIBILITY
2239_OutputIterator
2240remove_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, const _Tp& __value_)
2241{
2242    for (; __first != __last; ++__first)
2243    {
2244        if (!(*__first == __value_))
2245        {
2246            *__result = *__first;
2247            ++__result;
2248        }
2249    }
2250    return __result;
2251}
2252
2253// remove_copy_if
2254
2255template <class _InputIterator, class _OutputIterator, class _Predicate>
2256inline _LIBCPP_INLINE_VISIBILITY
2257_OutputIterator
2258remove_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Predicate __pred)
2259{
2260    for (; __first != __last; ++__first)
2261    {
2262        if (!__pred(*__first))
2263        {
2264            *__result = *__first;
2265            ++__result;
2266        }
2267    }
2268    return __result;
2269}
2270
2271// unique
2272
2273template <class _ForwardIterator, class _BinaryPredicate>
2274_ForwardIterator
2275unique(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
2276{
2277    __first = _VSTD::adjacent_find<_ForwardIterator, typename add_lvalue_reference<_BinaryPredicate>::type>
2278                                 (__first, __last, __pred);
2279    if (__first != __last)
2280    {
2281        // ...  a  a  ?  ...
2282        //      f     i
2283        _ForwardIterator __i = __first;
2284        for (++__i; ++__i != __last;)
2285            if (!__pred(*__first, *__i))
2286                *++__first = _VSTD::move(*__i);
2287        ++__first;
2288    }
2289    return __first;
2290}
2291
2292template <class _ForwardIterator>
2293inline _LIBCPP_INLINE_VISIBILITY
2294_ForwardIterator
2295unique(_ForwardIterator __first, _ForwardIterator __last)
2296{
2297    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
2298    return _VSTD::unique(__first, __last, __equal_to<__v>());
2299}
2300
2301// unique_copy
2302
2303template <class _BinaryPredicate, class _InputIterator, class _OutputIterator>
2304_OutputIterator
2305__unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred,
2306              input_iterator_tag, output_iterator_tag)
2307{
2308    if (__first != __last)
2309    {
2310        typename iterator_traits<_InputIterator>::value_type __t(*__first);
2311        *__result = __t;
2312        ++__result;
2313        while (++__first != __last)
2314        {
2315            if (!__pred(__t, *__first))
2316            {
2317                __t = *__first;
2318                *__result = __t;
2319                ++__result;
2320            }
2321        }
2322    }
2323    return __result;
2324}
2325
2326template <class _BinaryPredicate, class _ForwardIterator, class _OutputIterator>
2327_OutputIterator
2328__unique_copy(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result, _BinaryPredicate __pred,
2329              forward_iterator_tag, output_iterator_tag)
2330{
2331    if (__first != __last)
2332    {
2333        _ForwardIterator __i = __first;
2334        *__result = *__i;
2335        ++__result;
2336        while (++__first != __last)
2337        {
2338            if (!__pred(*__i, *__first))
2339            {
2340                *__result = *__first;
2341                ++__result;
2342                __i = __first;
2343            }
2344        }
2345    }
2346    return __result;
2347}
2348
2349template <class _BinaryPredicate, class _InputIterator, class _ForwardIterator>
2350_ForwardIterator
2351__unique_copy(_InputIterator __first, _InputIterator __last, _ForwardIterator __result, _BinaryPredicate __pred,
2352              input_iterator_tag, forward_iterator_tag)
2353{
2354    if (__first != __last)
2355    {
2356        *__result = *__first;
2357        while (++__first != __last)
2358            if (!__pred(*__result, *__first))
2359                *++__result = *__first;
2360        ++__result;
2361    }
2362    return __result;
2363}
2364
2365template <class _InputIterator, class _OutputIterator, class _BinaryPredicate>
2366inline _LIBCPP_INLINE_VISIBILITY
2367_OutputIterator
2368unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred)
2369{
2370    return _VSTD::__unique_copy<typename add_lvalue_reference<_BinaryPredicate>::type>
2371                              (__first, __last, __result, __pred,
2372                               typename iterator_traits<_InputIterator>::iterator_category(),
2373                               typename iterator_traits<_OutputIterator>::iterator_category());
2374}
2375
2376template <class _InputIterator, class _OutputIterator>
2377inline _LIBCPP_INLINE_VISIBILITY
2378_OutputIterator
2379unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
2380{
2381    typedef typename iterator_traits<_InputIterator>::value_type __v;
2382    return _VSTD::unique_copy(__first, __last, __result, __equal_to<__v>());
2383}
2384
2385// reverse
2386
2387template <class _BidirectionalIterator>
2388inline _LIBCPP_INLINE_VISIBILITY
2389void
2390__reverse(_BidirectionalIterator __first, _BidirectionalIterator __last, bidirectional_iterator_tag)
2391{
2392    while (__first != __last)
2393    {
2394        if (__first == --__last)
2395            break;
2396        _VSTD::iter_swap(__first, __last);
2397        ++__first;
2398    }
2399}
2400
2401template <class _RandomAccessIterator>
2402inline _LIBCPP_INLINE_VISIBILITY
2403void
2404__reverse(_RandomAccessIterator __first, _RandomAccessIterator __last, random_access_iterator_tag)
2405{
2406    if (__first != __last)
2407        for (; __first < --__last; ++__first)
2408            _VSTD::iter_swap(__first, __last);
2409}
2410
2411template <class _BidirectionalIterator>
2412inline _LIBCPP_INLINE_VISIBILITY
2413void
2414reverse(_BidirectionalIterator __first, _BidirectionalIterator __last)
2415{
2416    _VSTD::__reverse(__first, __last, typename iterator_traits<_BidirectionalIterator>::iterator_category());
2417}
2418
2419// reverse_copy
2420
2421template <class _BidirectionalIterator, class _OutputIterator>
2422inline _LIBCPP_INLINE_VISIBILITY
2423_OutputIterator
2424reverse_copy(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
2425{
2426    for (; __first != __last; ++__result)
2427        *__result = *--__last;
2428    return __result;
2429}
2430
2431// rotate
2432
2433template <class _ForwardIterator>
2434_ForwardIterator
2435__rotate_left(_ForwardIterator __first, _ForwardIterator __last)
2436{
2437    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
2438    value_type __tmp = _VSTD::move(*__first);
2439    _ForwardIterator __lm1 = _VSTD::move(_VSTD::next(__first), __last, __first);
2440    *__lm1 = _VSTD::move(__tmp);
2441    return __lm1;
2442}
2443
2444template <class _BidirectionalIterator>
2445_BidirectionalIterator
2446__rotate_right(_BidirectionalIterator __first, _BidirectionalIterator __last)
2447{
2448    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
2449    _BidirectionalIterator __lm1 = _VSTD::prev(__last);
2450    value_type __tmp = _VSTD::move(*__lm1);
2451    _BidirectionalIterator __fp1 = _VSTD::move_backward(__first, __lm1, __last);
2452    *__first = _VSTD::move(__tmp);
2453    return __fp1;
2454}
2455
2456template <class _ForwardIterator>
2457_ForwardIterator
2458__rotate_forward(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
2459{
2460    _ForwardIterator __i = __middle;
2461    while (true)
2462    {
2463        swap(*__first, *__i);
2464        ++__first;
2465        if (++__i == __last)
2466            break;
2467        if (__first == __middle)
2468            __middle = __i;
2469    }
2470    _ForwardIterator __r = __first;
2471    if (__first != __middle)
2472    {
2473        __i = __middle;
2474        while (true)
2475        {
2476            swap(*__first, *__i);
2477            ++__first;
2478            if (++__i == __last)
2479            {
2480                if (__first == __middle)
2481                    break;
2482                __i = __middle;
2483            }
2484            else if (__first == __middle)
2485                __middle = __i;
2486        }
2487    }
2488    return __r;
2489}
2490
2491template<typename _Integral>
2492inline _LIBCPP_INLINE_VISIBILITY
2493_Integral
2494__algo_gcd(_Integral __x, _Integral __y)
2495{
2496    do
2497    {
2498        _Integral __t = __x % __y;
2499        __x = __y;
2500        __y = __t;
2501    } while (__y);
2502    return __x;
2503}
2504
2505template<typename _RandomAccessIterator>
2506_RandomAccessIterator
2507__rotate_gcd(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)
2508{
2509    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
2510    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
2511
2512    const difference_type __m1 = __middle - __first;
2513    const difference_type __m2 = __last - __middle;
2514    if (__m1 == __m2)
2515    {
2516        _VSTD::swap_ranges(__first, __middle, __middle);
2517        return __middle;
2518    }
2519    const difference_type __g = _VSTD::__algo_gcd(__m1, __m2);
2520    for (_RandomAccessIterator __p = __first + __g; __p != __first;)
2521    {
2522        value_type __t(_VSTD::move(*--__p));
2523        _RandomAccessIterator __p1 = __p;
2524        _RandomAccessIterator __p2 = __p1 + __m1;
2525        do
2526        {
2527            *__p1 = _VSTD::move(*__p2);
2528            __p1 = __p2;
2529            const difference_type __d = __last - __p2;
2530            if (__m1 < __d)
2531                __p2 += __m1;
2532            else
2533                __p2 = __first + (__m1 - __d);
2534        } while (__p2 != __p);
2535        *__p1 = _VSTD::move(__t);
2536    }
2537    return __first + __m2;
2538}
2539
2540template <class _ForwardIterator>
2541inline _LIBCPP_INLINE_VISIBILITY
2542_ForwardIterator
2543__rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last,
2544         _VSTD::forward_iterator_tag)
2545{
2546    typedef typename _VSTD::iterator_traits<_ForwardIterator>::value_type value_type;
2547    if (_VSTD::is_trivially_move_assignable<value_type>::value)
2548    {
2549        if (_VSTD::next(__first) == __middle)
2550            return _VSTD::__rotate_left(__first, __last);
2551    }
2552    return _VSTD::__rotate_forward(__first, __middle, __last);
2553}
2554
2555template <class _BidirectionalIterator>
2556inline _LIBCPP_INLINE_VISIBILITY
2557_BidirectionalIterator
2558__rotate(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
2559         _VSTD::bidirectional_iterator_tag)
2560{
2561    typedef typename _VSTD::iterator_traits<_BidirectionalIterator>::value_type value_type;
2562    if (_VSTD::is_trivially_move_assignable<value_type>::value)
2563    {
2564        if (_VSTD::next(__first) == __middle)
2565            return _VSTD::__rotate_left(__first, __last);
2566        if (_VSTD::next(__middle) == __last)
2567            return _VSTD::__rotate_right(__first, __last);
2568    }
2569    return _VSTD::__rotate_forward(__first, __middle, __last);
2570}
2571
2572template <class _RandomAccessIterator>
2573inline _LIBCPP_INLINE_VISIBILITY
2574_RandomAccessIterator
2575__rotate(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
2576         _VSTD::random_access_iterator_tag)
2577{
2578    typedef typename _VSTD::iterator_traits<_RandomAccessIterator>::value_type value_type;
2579    if (_VSTD::is_trivially_move_assignable<value_type>::value)
2580    {
2581        if (_VSTD::next(__first) == __middle)
2582            return _VSTD::__rotate_left(__first, __last);
2583        if (_VSTD::next(__middle) == __last)
2584            return _VSTD::__rotate_right(__first, __last);
2585        return _VSTD::__rotate_gcd(__first, __middle, __last);
2586    }
2587    return _VSTD::__rotate_forward(__first, __middle, __last);
2588}
2589
2590template <class _ForwardIterator>
2591inline _LIBCPP_INLINE_VISIBILITY
2592_ForwardIterator
2593rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
2594{
2595    if (__first == __middle)
2596        return __last;
2597    if (__middle == __last)
2598        return __first;
2599    return _VSTD::__rotate(__first, __middle, __last,
2600                           typename _VSTD::iterator_traits<_ForwardIterator>::iterator_category());
2601}
2602
2603// rotate_copy
2604
2605template <class _ForwardIterator, class _OutputIterator>
2606inline _LIBCPP_INLINE_VISIBILITY
2607_OutputIterator
2608rotate_copy(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last, _OutputIterator __result)
2609{
2610    return _VSTD::copy(__first, __middle, _VSTD::copy(__middle, __last, __result));
2611}
2612
2613// min_element
2614
2615template <class _ForwardIterator, class _Compare>
2616inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2617_ForwardIterator
2618min_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2619{
2620    if (__first != __last)
2621    {
2622        _ForwardIterator __i = __first;
2623        while (++__i != __last)
2624            if (__comp(*__i, *__first))
2625                __first = __i;
2626    }
2627    return __first;
2628}
2629
2630template <class _ForwardIterator>
2631inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2632_ForwardIterator
2633min_element(_ForwardIterator __first, _ForwardIterator __last)
2634{
2635    return _VSTD::min_element(__first, __last,
2636              __less<typename iterator_traits<_ForwardIterator>::value_type>());
2637}
2638
2639// min
2640
2641template <class _Tp, class _Compare>
2642inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2643const _Tp&
2644min(const _Tp& __a, const _Tp& __b, _Compare __comp)
2645{
2646    return __comp(__b, __a) ? __b : __a;
2647}
2648
2649template <class _Tp>
2650inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2651const _Tp&
2652min(const _Tp& __a, const _Tp& __b)
2653{
2654    return _VSTD::min(__a, __b, __less<_Tp>());
2655}
2656
2657#ifndef _LIBCPP_CXX03_LANG
2658
2659template<class _Tp, class _Compare>
2660inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2661_Tp
2662min(initializer_list<_Tp> __t, _Compare __comp)
2663{
2664    return *_VSTD::min_element(__t.begin(), __t.end(), __comp);
2665}
2666
2667template<class _Tp>
2668inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2669_Tp
2670min(initializer_list<_Tp> __t)
2671{
2672    return *_VSTD::min_element(__t.begin(), __t.end(), __less<_Tp>());
2673}
2674
2675#endif  // _LIBCPP_CXX03_LANG
2676
2677// max_element
2678
2679template <class _ForwardIterator, class _Compare>
2680inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2681_ForwardIterator
2682max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2683{
2684    if (__first != __last)
2685    {
2686        _ForwardIterator __i = __first;
2687        while (++__i != __last)
2688            if (__comp(*__first, *__i))
2689                __first = __i;
2690    }
2691    return __first;
2692}
2693
2694
2695template <class _ForwardIterator>
2696inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2697_ForwardIterator
2698max_element(_ForwardIterator __first, _ForwardIterator __last)
2699{
2700    return _VSTD::max_element(__first, __last,
2701              __less<typename iterator_traits<_ForwardIterator>::value_type>());
2702}
2703
2704// max
2705
2706template <class _Tp, class _Compare>
2707inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2708const _Tp&
2709max(const _Tp& __a, const _Tp& __b, _Compare __comp)
2710{
2711    return __comp(__a, __b) ? __b : __a;
2712}
2713
2714template <class _Tp>
2715inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2716const _Tp&
2717max(const _Tp& __a, const _Tp& __b)
2718{
2719    return _VSTD::max(__a, __b, __less<_Tp>());
2720}
2721
2722#ifndef _LIBCPP_CXX03_LANG
2723
2724template<class _Tp, class _Compare>
2725inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2726_Tp
2727max(initializer_list<_Tp> __t, _Compare __comp)
2728{
2729    return *_VSTD::max_element(__t.begin(), __t.end(), __comp);
2730}
2731
2732template<class _Tp>
2733inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2734_Tp
2735max(initializer_list<_Tp> __t)
2736{
2737    return *_VSTD::max_element(__t.begin(), __t.end(), __less<_Tp>());
2738}
2739
2740#endif  // _LIBCPP_CXX03_LANG
2741
2742#if _LIBCPP_STD_VER > 14
2743// clamp
2744template<class _Tp, class _Compare>
2745inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2746const _Tp&
2747clamp(const _Tp& __v, const _Tp& __lo, const _Tp& __hi, _Compare __comp)
2748{
2749    _LIBCPP_ASSERT(!__comp(__hi, __lo), "Bad bounds passed to std::clamp");
2750    return __comp(__v, __lo) ? __lo : __comp(__hi, __v) ? __hi : __v;
2751
2752}
2753
2754template<class _Tp>
2755inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2756const _Tp&
2757clamp(const _Tp& __v, const _Tp& __lo, const _Tp& __hi)
2758{
2759    return _VSTD::clamp(__v, __lo, __hi, __less<_Tp>());
2760}
2761#endif
2762
2763// minmax_element
2764
2765template <class _ForwardIterator, class _Compare>
2766_LIBCPP_CONSTEXPR_AFTER_CXX11
2767std::pair<_ForwardIterator, _ForwardIterator>
2768minmax_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2769{
2770  std::pair<_ForwardIterator, _ForwardIterator> __result(__first, __first);
2771  if (__first != __last)
2772  {
2773      if (++__first != __last)
2774      {
2775          if (__comp(*__first, *__result.first))
2776              __result.first = __first;
2777          else
2778              __result.second = __first;
2779          while (++__first != __last)
2780          {
2781              _ForwardIterator __i = __first;
2782              if (++__first == __last)
2783              {
2784                  if (__comp(*__i, *__result.first))
2785                      __result.first = __i;
2786                  else if (!__comp(*__i, *__result.second))
2787                      __result.second = __i;
2788                  break;
2789              }
2790              else
2791              {
2792                  if (__comp(*__first, *__i))
2793                  {
2794                      if (__comp(*__first, *__result.first))
2795                          __result.first = __first;
2796                      if (!__comp(*__i, *__result.second))
2797                          __result.second = __i;
2798                  }
2799                  else
2800                  {
2801                      if (__comp(*__i, *__result.first))
2802                          __result.first = __i;
2803                      if (!__comp(*__first, *__result.second))
2804                          __result.second = __first;
2805                  }
2806              }
2807          }
2808      }
2809  }
2810  return __result;
2811}
2812
2813template <class _ForwardIterator>
2814inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2815std::pair<_ForwardIterator, _ForwardIterator>
2816minmax_element(_ForwardIterator __first, _ForwardIterator __last)
2817{
2818    return _VSTD::minmax_element(__first, __last,
2819              __less<typename iterator_traits<_ForwardIterator>::value_type>());
2820}
2821
2822// minmax
2823
2824template<class _Tp, class _Compare>
2825inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2826pair<const _Tp&, const _Tp&>
2827minmax(const _Tp& __a, const _Tp& __b, _Compare __comp)
2828{
2829    return __comp(__b, __a) ? pair<const _Tp&, const _Tp&>(__b, __a) :
2830                              pair<const _Tp&, const _Tp&>(__a, __b);
2831}
2832
2833template<class _Tp>
2834inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2835pair<const _Tp&, const _Tp&>
2836minmax(const _Tp& __a, const _Tp& __b)
2837{
2838    return _VSTD::minmax(__a, __b, __less<_Tp>());
2839}
2840
2841#ifndef _LIBCPP_CXX03_LANG
2842
2843template<class _Tp, class _Compare>
2844inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2845pair<_Tp, _Tp>
2846minmax(initializer_list<_Tp> __t, _Compare __comp)
2847{
2848    typedef typename initializer_list<_Tp>::const_iterator _Iter;
2849    _Iter __first = __t.begin();
2850    _Iter __last  = __t.end();
2851    std::pair<_Tp, _Tp> __result(*__first, *__first);
2852
2853    ++__first;
2854    if (__t.size() % 2 == 0)
2855    {
2856        if (__comp(*__first,  __result.first))
2857            __result.first  = *__first;
2858        else
2859            __result.second = *__first;
2860        ++__first;
2861    }
2862
2863    while (__first != __last)
2864    {
2865        _Tp __prev = *__first++;
2866        if (__comp(*__first, __prev)) {
2867            if ( __comp(*__first, __result.first)) __result.first  = *__first;
2868            if (!__comp(__prev, __result.second))  __result.second = __prev;
2869            }
2870        else {
2871            if ( __comp(__prev, __result.first))    __result.first  = __prev;
2872            if (!__comp(*__first, __result.second)) __result.second = *__first;
2873            }
2874
2875        __first++;
2876    }
2877    return __result;
2878}
2879
2880template<class _Tp>
2881inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2882pair<_Tp, _Tp>
2883minmax(initializer_list<_Tp> __t)
2884{
2885    return _VSTD::minmax(__t, __less<_Tp>());
2886}
2887
2888#endif  // _LIBCPP_CXX03_LANG
2889
2890// random_shuffle
2891
2892// __independent_bits_engine
2893
2894template <unsigned long long _Xp, size_t _Rp>
2895struct __log2_imp
2896{
2897    static const size_t value = _Xp & ((unsigned long long)(1) << _Rp) ? _Rp
2898                                           : __log2_imp<_Xp, _Rp - 1>::value;
2899};
2900
2901template <unsigned long long _Xp>
2902struct __log2_imp<_Xp, 0>
2903{
2904    static const size_t value = 0;
2905};
2906
2907template <size_t _Rp>
2908struct __log2_imp<0, _Rp>
2909{
2910    static const size_t value = _Rp + 1;
2911};
2912
2913template <class _UIntType, _UIntType _Xp>
2914struct __log2
2915{
2916    static const size_t value = __log2_imp<_Xp,
2917                                         sizeof(_UIntType) * __CHAR_BIT__ - 1>::value;
2918};
2919
2920template<class _Engine, class _UIntType>
2921class __independent_bits_engine
2922{
2923public:
2924    // types
2925    typedef _UIntType result_type;
2926
2927private:
2928    typedef typename _Engine::result_type _Engine_result_type;
2929    typedef typename conditional
2930        <
2931            sizeof(_Engine_result_type) <= sizeof(result_type),
2932                result_type,
2933                _Engine_result_type
2934        >::type _Working_result_type;
2935
2936    _Engine& __e_;
2937    size_t __w_;
2938    size_t __w0_;
2939    size_t __n_;
2940    size_t __n0_;
2941    _Working_result_type __y0_;
2942    _Working_result_type __y1_;
2943    _Engine_result_type __mask0_;
2944    _Engine_result_type __mask1_;
2945
2946#ifdef _LIBCPP_CXX03_LANG
2947    static const _Working_result_type _Rp = _Engine::_Max - _Engine::_Min
2948                                          + _Working_result_type(1);
2949#else
2950    static _LIBCPP_CONSTEXPR const _Working_result_type _Rp = _Engine::max() - _Engine::min()
2951                                                      + _Working_result_type(1);
2952#endif
2953    static _LIBCPP_CONSTEXPR const size_t __m = __log2<_Working_result_type, _Rp>::value;
2954    static _LIBCPP_CONSTEXPR const size_t _WDt = numeric_limits<_Working_result_type>::digits;
2955    static _LIBCPP_CONSTEXPR const size_t _EDt = numeric_limits<_Engine_result_type>::digits;
2956
2957public:
2958    // constructors and seeding functions
2959    __independent_bits_engine(_Engine& __e, size_t __w);
2960
2961    // generating functions
2962    result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
2963
2964private:
2965    result_type __eval(false_type);
2966    result_type __eval(true_type);
2967};
2968
2969template<class _Engine, class _UIntType>
2970__independent_bits_engine<_Engine, _UIntType>
2971    ::__independent_bits_engine(_Engine& __e, size_t __w)
2972        : __e_(__e),
2973          __w_(__w)
2974{
2975    __n_ = __w_ / __m + (__w_ % __m != 0);
2976    __w0_ = __w_ / __n_;
2977    if (_Rp == 0)
2978        __y0_ = _Rp;
2979    else if (__w0_ < _WDt)
2980        __y0_ = (_Rp >> __w0_) << __w0_;
2981    else
2982        __y0_ = 0;
2983    if (_Rp - __y0_ > __y0_ / __n_)
2984    {
2985        ++__n_;
2986        __w0_ = __w_ / __n_;
2987        if (__w0_ < _WDt)
2988            __y0_ = (_Rp >> __w0_) << __w0_;
2989        else
2990            __y0_ = 0;
2991    }
2992    __n0_ = __n_ - __w_ % __n_;
2993    if (__w0_ < _WDt - 1)
2994        __y1_ = (_Rp >> (__w0_ + 1)) << (__w0_ + 1);
2995    else
2996        __y1_ = 0;
2997    __mask0_ = __w0_ > 0 ? _Engine_result_type(~0) >> (_EDt - __w0_) :
2998                          _Engine_result_type(0);
2999    __mask1_ = __w0_ < _EDt - 1 ?
3000                               _Engine_result_type(~0) >> (_EDt - (__w0_ + 1)) :
3001                               _Engine_result_type(~0);
3002}
3003
3004template<class _Engine, class _UIntType>
3005inline
3006_UIntType
3007__independent_bits_engine<_Engine, _UIntType>::__eval(false_type)
3008{
3009    return static_cast<result_type>(__e_() & __mask0_);
3010}
3011
3012template<class _Engine, class _UIntType>
3013_UIntType
3014__independent_bits_engine<_Engine, _UIntType>::__eval(true_type)
3015{
3016    const size_t _WRt = numeric_limits<result_type>::digits;
3017    result_type _Sp = 0;
3018    for (size_t __k = 0; __k < __n0_; ++__k)
3019    {
3020        _Engine_result_type __u;
3021        do
3022        {
3023            __u = __e_() - _Engine::min();
3024        } while (__u >= __y0_);
3025        if (__w0_ < _WRt)
3026            _Sp <<= __w0_;
3027        else
3028            _Sp = 0;
3029        _Sp += __u & __mask0_;
3030    }
3031    for (size_t __k = __n0_; __k < __n_; ++__k)
3032    {
3033        _Engine_result_type __u;
3034        do
3035        {
3036            __u = __e_() - _Engine::min();
3037        } while (__u >= __y1_);
3038        if (__w0_ < _WRt - 1)
3039            _Sp <<= __w0_ + 1;
3040        else
3041            _Sp = 0;
3042        _Sp += __u & __mask1_;
3043    }
3044    return _Sp;
3045}
3046
3047// uniform_int_distribution
3048
3049template<class _IntType = int>
3050class uniform_int_distribution
3051{
3052public:
3053    // types
3054    typedef _IntType result_type;
3055
3056    class param_type
3057    {
3058        result_type __a_;
3059        result_type __b_;
3060    public:
3061        typedef uniform_int_distribution distribution_type;
3062
3063        explicit param_type(result_type __a = 0,
3064                            result_type __b = numeric_limits<result_type>::max())
3065            : __a_(__a), __b_(__b) {}
3066
3067        result_type a() const {return __a_;}
3068        result_type b() const {return __b_;}
3069
3070        friend bool operator==(const param_type& __x, const param_type& __y)
3071            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
3072        friend bool operator!=(const param_type& __x, const param_type& __y)
3073            {return !(__x == __y);}
3074    };
3075
3076private:
3077    param_type __p_;
3078
3079public:
3080    // constructors and reset functions
3081    explicit uniform_int_distribution(result_type __a = 0,
3082                                      result_type __b = numeric_limits<result_type>::max())
3083        : __p_(param_type(__a, __b)) {}
3084    explicit uniform_int_distribution(const param_type& __p) : __p_(__p) {}
3085    void reset() {}
3086
3087    // generating functions
3088    template<class _URNG> result_type operator()(_URNG& __g)
3089        {return (*this)(__g, __p_);}
3090    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
3091
3092    // property functions
3093    result_type a() const {return __p_.a();}
3094    result_type b() const {return __p_.b();}
3095
3096    param_type param() const {return __p_;}
3097    void param(const param_type& __p) {__p_ = __p;}
3098
3099    result_type min() const {return a();}
3100    result_type max() const {return b();}
3101
3102    friend bool operator==(const uniform_int_distribution& __x,
3103                           const uniform_int_distribution& __y)
3104        {return __x.__p_ == __y.__p_;}
3105    friend bool operator!=(const uniform_int_distribution& __x,
3106                           const uniform_int_distribution& __y)
3107            {return !(__x == __y);}
3108};
3109
3110template<class _IntType>
3111template<class _URNG>
3112typename uniform_int_distribution<_IntType>::result_type
3113uniform_int_distribution<_IntType>::operator()(_URNG& __g, const param_type& __p)
3114{
3115    typedef typename conditional<sizeof(result_type) <= sizeof(uint32_t),
3116                                            uint32_t, uint64_t>::type _UIntType;
3117    const _UIntType _Rp = __p.b() - __p.a() + _UIntType(1);
3118    if (_Rp == 1)
3119        return __p.a();
3120    const size_t _Dt = numeric_limits<_UIntType>::digits;
3121    typedef __independent_bits_engine<_URNG, _UIntType> _Eng;
3122    if (_Rp == 0)
3123        return static_cast<result_type>(_Eng(__g, _Dt)());
3124    size_t __w = _Dt - __clz(_Rp) - 1;
3125    if ((_Rp & (std::numeric_limits<_UIntType>::max() >> (_Dt - __w))) != 0)
3126        ++__w;
3127    _Eng __e(__g, __w);
3128    _UIntType __u;
3129    do
3130    {
3131        __u = __e();
3132    } while (__u >= _Rp);
3133    return static_cast<result_type>(__u + __p.a());
3134}
3135
3136#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_RANDOM_SHUFFLE) \
3137  || defined(_LIBCPP_BUILDING_LIBRARY)
3138class _LIBCPP_TYPE_VIS __rs_default;
3139
3140_LIBCPP_FUNC_VIS __rs_default __rs_get();
3141
3142class _LIBCPP_TYPE_VIS __rs_default
3143{
3144    static unsigned __c_;
3145
3146    __rs_default();
3147public:
3148    typedef uint_fast32_t result_type;
3149
3150    static const result_type _Min = 0;
3151    static const result_type _Max = 0xFFFFFFFF;
3152
3153    __rs_default(const __rs_default&);
3154    ~__rs_default();
3155
3156    result_type operator()();
3157
3158    static _LIBCPP_CONSTEXPR result_type min() {return _Min;}
3159    static _LIBCPP_CONSTEXPR result_type max() {return _Max;}
3160
3161    friend _LIBCPP_FUNC_VIS __rs_default __rs_get();
3162};
3163
3164_LIBCPP_FUNC_VIS __rs_default __rs_get();
3165
3166template <class _RandomAccessIterator>
3167void
3168random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)
3169{
3170    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3171    typedef uniform_int_distribution<ptrdiff_t> _Dp;
3172    typedef typename _Dp::param_type _Pp;
3173    difference_type __d = __last - __first;
3174    if (__d > 1)
3175    {
3176        _Dp __uid;
3177        __rs_default __g = __rs_get();
3178        for (--__last, --__d; __first < __last; ++__first, --__d)
3179        {
3180            difference_type __i = __uid(__g, _Pp(0, __d));
3181            if (__i != difference_type(0))
3182                swap(*__first, *(__first + __i));
3183        }
3184    }
3185}
3186
3187template <class _RandomAccessIterator, class _RandomNumberGenerator>
3188void
3189random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
3190#ifndef _LIBCPP_CXX03_LANG
3191               _RandomNumberGenerator&& __rand)
3192#else
3193               _RandomNumberGenerator& __rand)
3194#endif
3195{
3196    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3197    difference_type __d = __last - __first;
3198    if (__d > 1)
3199    {
3200        for (--__last; __first < __last; ++__first, --__d)
3201        {
3202            difference_type __i = __rand(__d);
3203            swap(*__first, *(__first + __i));
3204        }
3205    }
3206}
3207#endif
3208
3209template <class _PopulationIterator, class _SampleIterator, class _Distance,
3210          class _UniformRandomNumberGenerator>
3211_LIBCPP_INLINE_VISIBILITY
3212_SampleIterator __sample(_PopulationIterator __first,
3213                         _PopulationIterator __last, _SampleIterator __output_iter,
3214                         _Distance __n,
3215                         _UniformRandomNumberGenerator & __g,
3216                         input_iterator_tag) {
3217
3218  _Distance __k = 0;
3219  for (; __first != __last && __k < __n; ++__first, (void)++__k)
3220    __output_iter[__k] = *__first;
3221  _Distance __sz = __k;
3222  for (; __first != __last; ++__first, (void)++__k) {
3223    _Distance __r = _VSTD::uniform_int_distribution<_Distance>(0, __k)(__g);
3224    if (__r < __sz)
3225      __output_iter[__r] = *__first;
3226  }
3227  return __output_iter + _VSTD::min(__n, __k);
3228}
3229
3230template <class _PopulationIterator, class _SampleIterator, class _Distance,
3231          class _UniformRandomNumberGenerator>
3232_LIBCPP_INLINE_VISIBILITY
3233_SampleIterator __sample(_PopulationIterator __first,
3234                         _PopulationIterator __last, _SampleIterator __output_iter,
3235                         _Distance __n,
3236                         _UniformRandomNumberGenerator& __g,
3237                         forward_iterator_tag) {
3238  _Distance __unsampled_sz = _VSTD::distance(__first, __last);
3239  for (__n = _VSTD::min(__n, __unsampled_sz); __n != 0; ++__first) {
3240    _Distance __r =
3241        _VSTD::uniform_int_distribution<_Distance>(0, --__unsampled_sz)(__g);
3242    if (__r < __n) {
3243      *__output_iter++ = *__first;
3244      --__n;
3245    }
3246  }
3247  return __output_iter;
3248}
3249
3250template <class _PopulationIterator, class _SampleIterator, class _Distance,
3251          class _UniformRandomNumberGenerator>
3252_LIBCPP_INLINE_VISIBILITY
3253_SampleIterator __sample(_PopulationIterator __first,
3254                         _PopulationIterator __last, _SampleIterator __output_iter,
3255                         _Distance __n, _UniformRandomNumberGenerator& __g) {
3256  typedef typename iterator_traits<_PopulationIterator>::iterator_category
3257        _PopCategory;
3258  typedef typename iterator_traits<_PopulationIterator>::difference_type
3259        _Difference;
3260  static_assert(__is_forward_iterator<_PopulationIterator>::value ||
3261                __is_random_access_iterator<_SampleIterator>::value,
3262                "SampleIterator must meet the requirements of RandomAccessIterator");
3263  typedef typename common_type<_Distance, _Difference>::type _CommonType;
3264  _LIBCPP_ASSERT(__n >= 0, "N must be a positive number.");
3265  return _VSTD::__sample(
3266      __first, __last, __output_iter, _CommonType(__n),
3267      __g, _PopCategory());
3268}
3269
3270#if _LIBCPP_STD_VER > 14
3271template <class _PopulationIterator, class _SampleIterator, class _Distance,
3272          class _UniformRandomNumberGenerator>
3273inline _LIBCPP_INLINE_VISIBILITY
3274_SampleIterator sample(_PopulationIterator __first,
3275                       _PopulationIterator __last, _SampleIterator __output_iter,
3276                       _Distance __n, _UniformRandomNumberGenerator&& __g) {
3277    return _VSTD::__sample(__first, __last, __output_iter, __n, __g);
3278}
3279#endif // _LIBCPP_STD_VER > 14
3280
3281template<class _RandomAccessIterator, class _UniformRandomNumberGenerator>
3282    void shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
3283#ifndef _LIBCPP_CXX03_LANG
3284                 _UniformRandomNumberGenerator&& __g)
3285#else
3286                 _UniformRandomNumberGenerator& __g)
3287#endif
3288{
3289    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3290    typedef uniform_int_distribution<ptrdiff_t> _Dp;
3291    typedef typename _Dp::param_type _Pp;
3292    difference_type __d = __last - __first;
3293    if (__d > 1)
3294    {
3295        _Dp __uid;
3296        for (--__last, --__d; __first < __last; ++__first, --__d)
3297        {
3298            difference_type __i = __uid(__g, _Pp(0, __d));
3299            if (__i != difference_type(0))
3300                swap(*__first, *(__first + __i));
3301        }
3302    }
3303}
3304
3305template <class _InputIterator, class _Predicate>
3306bool
3307is_partitioned(_InputIterator __first, _InputIterator __last, _Predicate __pred)
3308{
3309    for (; __first != __last; ++__first)
3310        if (!__pred(*__first))
3311            break;
3312    if ( __first == __last )
3313        return true;
3314    ++__first;
3315    for (; __first != __last; ++__first)
3316        if (__pred(*__first))
3317            return false;
3318    return true;
3319}
3320
3321// partition
3322
3323template <class _Predicate, class _ForwardIterator>
3324_ForwardIterator
3325__partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, forward_iterator_tag)
3326{
3327    while (true)
3328    {
3329        if (__first == __last)
3330            return __first;
3331        if (!__pred(*__first))
3332            break;
3333        ++__first;
3334    }
3335    for (_ForwardIterator __p = __first; ++__p != __last;)
3336    {
3337        if (__pred(*__p))
3338        {
3339            swap(*__first, *__p);
3340            ++__first;
3341        }
3342    }
3343    return __first;
3344}
3345
3346template <class _Predicate, class _BidirectionalIterator>
3347_BidirectionalIterator
3348__partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
3349            bidirectional_iterator_tag)
3350{
3351    while (true)
3352    {
3353        while (true)
3354        {
3355            if (__first == __last)
3356                return __first;
3357            if (!__pred(*__first))
3358                break;
3359            ++__first;
3360        }
3361        do
3362        {
3363            if (__first == --__last)
3364                return __first;
3365        } while (!__pred(*__last));
3366        swap(*__first, *__last);
3367        ++__first;
3368    }
3369}
3370
3371template <class _ForwardIterator, class _Predicate>
3372inline _LIBCPP_INLINE_VISIBILITY
3373_ForwardIterator
3374partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
3375{
3376    return _VSTD::__partition<typename add_lvalue_reference<_Predicate>::type>
3377                            (__first, __last, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
3378}
3379
3380// partition_copy
3381
3382template <class _InputIterator, class _OutputIterator1,
3383          class _OutputIterator2, class _Predicate>
3384pair<_OutputIterator1, _OutputIterator2>
3385partition_copy(_InputIterator __first, _InputIterator __last,
3386               _OutputIterator1 __out_true, _OutputIterator2 __out_false,
3387               _Predicate __pred)
3388{
3389    for (; __first != __last; ++__first)
3390    {
3391        if (__pred(*__first))
3392        {
3393            *__out_true = *__first;
3394            ++__out_true;
3395        }
3396        else
3397        {
3398            *__out_false = *__first;
3399            ++__out_false;
3400        }
3401    }
3402    return pair<_OutputIterator1, _OutputIterator2>(__out_true, __out_false);
3403}
3404
3405// partition_point
3406
3407template<class _ForwardIterator, class _Predicate>
3408_ForwardIterator
3409partition_point(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
3410{
3411    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
3412    difference_type __len = _VSTD::distance(__first, __last);
3413    while (__len != 0)
3414    {
3415        difference_type __l2 = __len / 2;
3416        _ForwardIterator __m = __first;
3417        _VSTD::advance(__m, __l2);
3418        if (__pred(*__m))
3419        {
3420            __first = ++__m;
3421            __len -= __l2 + 1;
3422        }
3423        else
3424            __len = __l2;
3425    }
3426    return __first;
3427}
3428
3429// stable_partition
3430
3431template <class _Predicate, class _ForwardIterator, class _Distance, class _Pair>
3432_ForwardIterator
3433__stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred,
3434                   _Distance __len, _Pair __p, forward_iterator_tag __fit)
3435{
3436    // *__first is known to be false
3437    // __len >= 1
3438    if (__len == 1)
3439        return __first;
3440    if (__len == 2)
3441    {
3442        _ForwardIterator __m = __first;
3443        if (__pred(*++__m))
3444        {
3445            swap(*__first, *__m);
3446            return __m;
3447        }
3448        return __first;
3449    }
3450    if (__len <= __p.second)
3451    {   // The buffer is big enough to use
3452        typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
3453        __destruct_n __d(0);
3454        unique_ptr<value_type, __destruct_n&> __h(__p.first, __d);
3455        // Move the falses into the temporary buffer, and the trues to the front of the line
3456        // Update __first to always point to the end of the trues
3457        value_type* __t = __p.first;
3458        ::new(__t) value_type(_VSTD::move(*__first));
3459        __d.__incr((value_type*)0);
3460        ++__t;
3461        _ForwardIterator __i = __first;
3462        while (++__i != __last)
3463        {
3464            if (__pred(*__i))
3465            {
3466                *__first = _VSTD::move(*__i);
3467                ++__first;
3468            }
3469            else
3470            {
3471                ::new(__t) value_type(_VSTD::move(*__i));
3472                __d.__incr((value_type*)0);
3473                ++__t;
3474            }
3475        }
3476        // All trues now at start of range, all falses in buffer
3477        // Move falses back into range, but don't mess up __first which points to first false
3478        __i = __first;
3479        for (value_type* __t2 = __p.first; __t2 < __t; ++__t2, ++__i)
3480            *__i = _VSTD::move(*__t2);
3481        // __h destructs moved-from values out of the temp buffer, but doesn't deallocate buffer
3482        return __first;
3483    }
3484    // Else not enough buffer, do in place
3485    // __len >= 3
3486    _ForwardIterator __m = __first;
3487    _Distance __len2 = __len / 2;  // __len2 >= 2
3488    _VSTD::advance(__m, __len2);
3489    // recurse on [__first, __m), *__first know to be false
3490    // F?????????????????
3491    // f       m         l
3492    typedef typename add_lvalue_reference<_Predicate>::type _PredRef;
3493    _ForwardIterator __first_false = __stable_partition<_PredRef>(__first, __m, __pred, __len2, __p, __fit);
3494    // TTTFFFFF??????????
3495    // f  ff   m         l
3496    // recurse on [__m, __last], except increase __m until *(__m) is false, *__last know to be true
3497    _ForwardIterator __m1 = __m;
3498    _ForwardIterator __second_false = __last;
3499    _Distance __len_half = __len - __len2;
3500    while (__pred(*__m1))
3501    {
3502        if (++__m1 == __last)
3503            goto __second_half_done;
3504        --__len_half;
3505    }
3506    // TTTFFFFFTTTF??????
3507    // f  ff   m  m1     l
3508    __second_false = __stable_partition<_PredRef>(__m1, __last, __pred, __len_half, __p, __fit);
3509__second_half_done:
3510    // TTTFFFFFTTTTTFFFFF
3511    // f  ff   m    sf   l
3512    return _VSTD::rotate(__first_false, __m, __second_false);
3513    // TTTTTTTTFFFFFFFFFF
3514    //         |
3515}
3516
3517struct __return_temporary_buffer
3518{
3519    template <class _Tp>
3520    _LIBCPP_INLINE_VISIBILITY void operator()(_Tp* __p) const {_VSTD::return_temporary_buffer(__p);}
3521};
3522
3523template <class _Predicate, class _ForwardIterator>
3524_ForwardIterator
3525__stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred,
3526                   forward_iterator_tag)
3527{
3528    const unsigned __alloc_limit = 3;  // might want to make this a function of trivial assignment
3529    // Either prove all true and return __first or point to first false
3530    while (true)
3531    {
3532        if (__first == __last)
3533            return __first;
3534        if (!__pred(*__first))
3535            break;
3536        ++__first;
3537    }
3538    // We now have a reduced range [__first, __last)
3539    // *__first is known to be false
3540    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
3541    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
3542    difference_type __len = _VSTD::distance(__first, __last);
3543    pair<value_type*, ptrdiff_t> __p(0, 0);
3544    unique_ptr<value_type, __return_temporary_buffer> __h;
3545    if (__len >= __alloc_limit)
3546    {
3547        __p = _VSTD::get_temporary_buffer<value_type>(__len);
3548        __h.reset(__p.first);
3549    }
3550    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
3551                             (__first, __last, __pred, __len, __p, forward_iterator_tag());
3552}
3553
3554template <class _Predicate, class _BidirectionalIterator, class _Distance, class _Pair>
3555_BidirectionalIterator
3556__stable_partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
3557                   _Distance __len, _Pair __p, bidirectional_iterator_tag __bit)
3558{
3559    // *__first is known to be false
3560    // *__last is known to be true
3561    // __len >= 2
3562    if (__len == 2)
3563    {
3564        swap(*__first, *__last);
3565        return __last;
3566    }
3567    if (__len == 3)
3568    {
3569        _BidirectionalIterator __m = __first;
3570        if (__pred(*++__m))
3571        {
3572            swap(*__first, *__m);
3573            swap(*__m, *__last);
3574            return __last;
3575        }
3576        swap(*__m, *__last);
3577        swap(*__first, *__m);
3578        return __m;
3579    }
3580    if (__len <= __p.second)
3581    {   // The buffer is big enough to use
3582        typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
3583        __destruct_n __d(0);
3584        unique_ptr<value_type, __destruct_n&> __h(__p.first, __d);
3585        // Move the falses into the temporary buffer, and the trues to the front of the line
3586        // Update __first to always point to the end of the trues
3587        value_type* __t = __p.first;
3588        ::new(__t) value_type(_VSTD::move(*__first));
3589        __d.__incr((value_type*)0);
3590        ++__t;
3591        _BidirectionalIterator __i = __first;
3592        while (++__i != __last)
3593        {
3594            if (__pred(*__i))
3595            {
3596                *__first = _VSTD::move(*__i);
3597                ++__first;
3598            }
3599            else
3600            {
3601                ::new(__t) value_type(_VSTD::move(*__i));
3602                __d.__incr((value_type*)0);
3603                ++__t;
3604            }
3605        }
3606        // move *__last, known to be true
3607        *__first = _VSTD::move(*__i);
3608        __i = ++__first;
3609        // All trues now at start of range, all falses in buffer
3610        // Move falses back into range, but don't mess up __first which points to first false
3611        for (value_type* __t2 = __p.first; __t2 < __t; ++__t2, ++__i)
3612            *__i = _VSTD::move(*__t2);
3613        // __h destructs moved-from values out of the temp buffer, but doesn't deallocate buffer
3614        return __first;
3615    }
3616    // Else not enough buffer, do in place
3617    // __len >= 4
3618    _BidirectionalIterator __m = __first;
3619    _Distance __len2 = __len / 2;  // __len2 >= 2
3620    _VSTD::advance(__m, __len2);
3621    // recurse on [__first, __m-1], except reduce __m-1 until *(__m-1) is true, *__first know to be false
3622    // F????????????????T
3623    // f       m        l
3624    _BidirectionalIterator __m1 = __m;
3625    _BidirectionalIterator __first_false = __first;
3626    _Distance __len_half = __len2;
3627    while (!__pred(*--__m1))
3628    {
3629        if (__m1 == __first)
3630            goto __first_half_done;
3631        --__len_half;
3632    }
3633    // F???TFFF?????????T
3634    // f   m1  m        l
3635    typedef typename add_lvalue_reference<_Predicate>::type _PredRef;
3636    __first_false = __stable_partition<_PredRef>(__first, __m1, __pred, __len_half, __p, __bit);
3637__first_half_done:
3638    // TTTFFFFF?????????T
3639    // f  ff   m        l
3640    // recurse on [__m, __last], except increase __m until *(__m) is false, *__last know to be true
3641    __m1 = __m;
3642    _BidirectionalIterator __second_false = __last;
3643    ++__second_false;
3644    __len_half = __len - __len2;
3645    while (__pred(*__m1))
3646    {
3647        if (++__m1 == __last)
3648            goto __second_half_done;
3649        --__len_half;
3650    }
3651    // TTTFFFFFTTTF?????T
3652    // f  ff   m  m1    l
3653    __second_false = __stable_partition<_PredRef>(__m1, __last, __pred, __len_half, __p, __bit);
3654__second_half_done:
3655    // TTTFFFFFTTTTTFFFFF
3656    // f  ff   m    sf  l
3657    return _VSTD::rotate(__first_false, __m, __second_false);
3658    // TTTTTTTTFFFFFFFFFF
3659    //         |
3660}
3661
3662template <class _Predicate, class _BidirectionalIterator>
3663_BidirectionalIterator
3664__stable_partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
3665                   bidirectional_iterator_tag)
3666{
3667    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
3668    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
3669    const difference_type __alloc_limit = 4;  // might want to make this a function of trivial assignment
3670    // Either prove all true and return __first or point to first false
3671    while (true)
3672    {
3673        if (__first == __last)
3674            return __first;
3675        if (!__pred(*__first))
3676            break;
3677        ++__first;
3678    }
3679    // __first points to first false, everything prior to __first is already set.
3680    // Either prove [__first, __last) is all false and return __first, or point __last to last true
3681    do
3682    {
3683        if (__first == --__last)
3684            return __first;
3685    } while (!__pred(*__last));
3686    // We now have a reduced range [__first, __last]
3687    // *__first is known to be false
3688    // *__last is known to be true
3689    // __len >= 2
3690    difference_type __len = _VSTD::distance(__first, __last) + 1;
3691    pair<value_type*, ptrdiff_t> __p(0, 0);
3692    unique_ptr<value_type, __return_temporary_buffer> __h;
3693    if (__len >= __alloc_limit)
3694    {
3695        __p = _VSTD::get_temporary_buffer<value_type>(__len);
3696        __h.reset(__p.first);
3697    }
3698    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
3699                             (__first, __last, __pred, __len, __p, bidirectional_iterator_tag());
3700}
3701
3702template <class _ForwardIterator, class _Predicate>
3703inline _LIBCPP_INLINE_VISIBILITY
3704_ForwardIterator
3705stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
3706{
3707    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
3708                             (__first, __last, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
3709}
3710
3711// is_sorted_until
3712
3713template <class _ForwardIterator, class _Compare>
3714_ForwardIterator
3715is_sorted_until(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
3716{
3717    if (__first != __last)
3718    {
3719        _ForwardIterator __i = __first;
3720        while (++__i != __last)
3721        {
3722            if (__comp(*__i, *__first))
3723                return __i;
3724            __first = __i;
3725        }
3726    }
3727    return __last;
3728}
3729
3730template<class _ForwardIterator>
3731inline _LIBCPP_INLINE_VISIBILITY
3732_ForwardIterator
3733is_sorted_until(_ForwardIterator __first, _ForwardIterator __last)
3734{
3735    return _VSTD::is_sorted_until(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
3736}
3737
3738// is_sorted
3739
3740template <class _ForwardIterator, class _Compare>
3741inline _LIBCPP_INLINE_VISIBILITY
3742bool
3743is_sorted(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
3744{
3745    return _VSTD::is_sorted_until(__first, __last, __comp) == __last;
3746}
3747
3748template<class _ForwardIterator>
3749inline _LIBCPP_INLINE_VISIBILITY
3750bool
3751is_sorted(_ForwardIterator __first, _ForwardIterator __last)
3752{
3753    return _VSTD::is_sorted(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
3754}
3755
3756// sort
3757
3758// stable, 2-3 compares, 0-2 swaps
3759
3760template <class _Compare, class _ForwardIterator>
3761unsigned
3762__sort3(_ForwardIterator __x, _ForwardIterator __y, _ForwardIterator __z, _Compare __c)
3763{
3764    unsigned __r = 0;
3765    if (!__c(*__y, *__x))          // if x <= y
3766    {
3767        if (!__c(*__z, *__y))      // if y <= z
3768            return __r;            // x <= y && y <= z
3769                                   // x <= y && y > z
3770        swap(*__y, *__z);          // x <= z && y < z
3771        __r = 1;
3772        if (__c(*__y, *__x))       // if x > y
3773        {
3774            swap(*__x, *__y);      // x < y && y <= z
3775            __r = 2;
3776        }
3777        return __r;                // x <= y && y < z
3778    }
3779    if (__c(*__z, *__y))           // x > y, if y > z
3780    {
3781        swap(*__x, *__z);          // x < y && y < z
3782        __r = 1;
3783        return __r;
3784    }
3785    swap(*__x, *__y);              // x > y && y <= z
3786    __r = 1;                       // x < y && x <= z
3787    if (__c(*__z, *__y))           // if y > z
3788    {
3789        swap(*__y, *__z);          // x <= y && y < z
3790        __r = 2;
3791    }
3792    return __r;
3793}                                  // x <= y && y <= z
3794
3795// stable, 3-6 compares, 0-5 swaps
3796
3797template <class _Compare, class _ForwardIterator>
3798unsigned
3799__sort4(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3,
3800            _ForwardIterator __x4, _Compare __c)
3801{
3802    unsigned __r = __sort3<_Compare>(__x1, __x2, __x3, __c);
3803    if (__c(*__x4, *__x3))
3804    {
3805        swap(*__x3, *__x4);
3806        ++__r;
3807        if (__c(*__x3, *__x2))
3808        {
3809            swap(*__x2, *__x3);
3810            ++__r;
3811            if (__c(*__x2, *__x1))
3812            {
3813                swap(*__x1, *__x2);
3814                ++__r;
3815            }
3816        }
3817    }
3818    return __r;
3819}
3820
3821// stable, 4-10 compares, 0-9 swaps
3822
3823template <class _Compare, class _ForwardIterator>
3824unsigned
3825__sort5(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3,
3826            _ForwardIterator __x4, _ForwardIterator __x5, _Compare __c)
3827{
3828    unsigned __r = __sort4<_Compare>(__x1, __x2, __x3, __x4, __c);
3829    if (__c(*__x5, *__x4))
3830    {
3831        swap(*__x4, *__x5);
3832        ++__r;
3833        if (__c(*__x4, *__x3))
3834        {
3835            swap(*__x3, *__x4);
3836            ++__r;
3837            if (__c(*__x3, *__x2))
3838            {
3839                swap(*__x2, *__x3);
3840                ++__r;
3841                if (__c(*__x2, *__x1))
3842                {
3843                    swap(*__x1, *__x2);
3844                    ++__r;
3845                }
3846            }
3847        }
3848    }
3849    return __r;
3850}
3851
3852// Assumes size > 0
3853template <class _Compare, class _BirdirectionalIterator>
3854void
3855__selection_sort(_BirdirectionalIterator __first, _BirdirectionalIterator __last, _Compare __comp)
3856{
3857    _BirdirectionalIterator __lm1 = __last;
3858    for (--__lm1; __first != __lm1; ++__first)
3859    {
3860        _BirdirectionalIterator __i = _VSTD::min_element<_BirdirectionalIterator,
3861                                                        typename add_lvalue_reference<_Compare>::type>
3862                                                       (__first, __last, __comp);
3863        if (__i != __first)
3864            swap(*__first, *__i);
3865    }
3866}
3867
3868template <class _Compare, class _BirdirectionalIterator>
3869void
3870__insertion_sort(_BirdirectionalIterator __first, _BirdirectionalIterator __last, _Compare __comp)
3871{
3872    typedef typename iterator_traits<_BirdirectionalIterator>::value_type value_type;
3873    if (__first != __last)
3874    {
3875        _BirdirectionalIterator __i = __first;
3876        for (++__i; __i != __last; ++__i)
3877        {
3878            _BirdirectionalIterator __j = __i;
3879            value_type __t(_VSTD::move(*__j));
3880            for (_BirdirectionalIterator __k = __i; __k != __first && __comp(__t,  *--__k); --__j)
3881                *__j = _VSTD::move(*__k);
3882            *__j = _VSTD::move(__t);
3883        }
3884    }
3885}
3886
3887template <class _Compare, class _RandomAccessIterator>
3888void
3889__insertion_sort_3(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
3890{
3891    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
3892    _RandomAccessIterator __j = __first+2;
3893    __sort3<_Compare>(__first, __first+1, __j, __comp);
3894    for (_RandomAccessIterator __i = __j+1; __i != __last; ++__i)
3895    {
3896        if (__comp(*__i, *__j))
3897        {
3898            value_type __t(_VSTD::move(*__i));
3899            _RandomAccessIterator __k = __j;
3900            __j = __i;
3901            do
3902            {
3903                *__j = _VSTD::move(*__k);
3904                __j = __k;
3905            } while (__j != __first && __comp(__t, *--__k));
3906            *__j = _VSTD::move(__t);
3907        }
3908        __j = __i;
3909    }
3910}
3911
3912template <class _Compare, class _RandomAccessIterator>
3913bool
3914__insertion_sort_incomplete(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
3915{
3916    switch (__last - __first)
3917    {
3918    case 0:
3919    case 1:
3920        return true;
3921    case 2:
3922        if (__comp(*--__last, *__first))
3923            swap(*__first, *__last);
3924        return true;
3925    case 3:
3926        _VSTD::__sort3<_Compare>(__first, __first+1, --__last, __comp);
3927        return true;
3928    case 4:
3929        _VSTD::__sort4<_Compare>(__first, __first+1, __first+2, --__last, __comp);
3930        return true;
3931    case 5:
3932        _VSTD::__sort5<_Compare>(__first, __first+1, __first+2, __first+3, --__last, __comp);
3933        return true;
3934    }
3935    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
3936    _RandomAccessIterator __j = __first+2;
3937    __sort3<_Compare>(__first, __first+1, __j, __comp);
3938    const unsigned __limit = 8;
3939    unsigned __count = 0;
3940    for (_RandomAccessIterator __i = __j+1; __i != __last; ++__i)
3941    {
3942        if (__comp(*__i, *__j))
3943        {
3944            value_type __t(_VSTD::move(*__i));
3945            _RandomAccessIterator __k = __j;
3946            __j = __i;
3947            do
3948            {
3949                *__j = _VSTD::move(*__k);
3950                __j = __k;
3951            } while (__j != __first && __comp(__t, *--__k));
3952            *__j = _VSTD::move(__t);
3953            if (++__count == __limit)
3954                return ++__i == __last;
3955        }
3956        __j = __i;
3957    }
3958    return true;
3959}
3960
3961template <class _Compare, class _BirdirectionalIterator>
3962void
3963__insertion_sort_move(_BirdirectionalIterator __first1, _BirdirectionalIterator __last1,
3964                      typename iterator_traits<_BirdirectionalIterator>::value_type* __first2, _Compare __comp)
3965{
3966    typedef typename iterator_traits<_BirdirectionalIterator>::value_type value_type;
3967    if (__first1 != __last1)
3968    {
3969        __destruct_n __d(0);
3970        unique_ptr<value_type, __destruct_n&> __h(__first2, __d);
3971        value_type* __last2 = __first2;
3972        ::new(__last2) value_type(_VSTD::move(*__first1));
3973        __d.__incr((value_type*)0);
3974        for (++__last2; ++__first1 != __last1; ++__last2)
3975        {
3976            value_type* __j2 = __last2;
3977            value_type* __i2 = __j2;
3978            if (__comp(*__first1, *--__i2))
3979            {
3980                ::new(__j2) value_type(_VSTD::move(*__i2));
3981                __d.__incr((value_type*)0);
3982                for (--__j2; __i2 != __first2 && __comp(*__first1,  *--__i2); --__j2)
3983                    *__j2 = _VSTD::move(*__i2);
3984                *__j2 = _VSTD::move(*__first1);
3985            }
3986            else
3987            {
3988                ::new(__j2) value_type(_VSTD::move(*__first1));
3989                __d.__incr((value_type*)0);
3990            }
3991        }
3992        __h.release();
3993    }
3994}
3995
3996template <class _Compare, class _RandomAccessIterator>
3997void
3998__sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
3999{
4000    // _Compare is known to be a reference type
4001    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4002    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4003    const difference_type __limit = is_trivially_copy_constructible<value_type>::value &&
4004                                    is_trivially_copy_assignable<value_type>::value ? 30 : 6;
4005    while (true)
4006    {
4007    __restart:
4008        difference_type __len = __last - __first;
4009        switch (__len)
4010        {
4011        case 0:
4012        case 1:
4013            return;
4014        case 2:
4015            if (__comp(*--__last, *__first))
4016                swap(*__first, *__last);
4017            return;
4018        case 3:
4019            _VSTD::__sort3<_Compare>(__first, __first+1, --__last, __comp);
4020            return;
4021        case 4:
4022            _VSTD::__sort4<_Compare>(__first, __first+1, __first+2, --__last, __comp);
4023            return;
4024        case 5:
4025            _VSTD::__sort5<_Compare>(__first, __first+1, __first+2, __first+3, --__last, __comp);
4026            return;
4027        }
4028        if (__len <= __limit)
4029        {
4030            _VSTD::__insertion_sort_3<_Compare>(__first, __last, __comp);
4031            return;
4032        }
4033        // __len > 5
4034        _RandomAccessIterator __m = __first;
4035        _RandomAccessIterator __lm1 = __last;
4036        --__lm1;
4037        unsigned __n_swaps;
4038        {
4039        difference_type __delta;
4040        if (__len >= 1000)
4041        {
4042            __delta = __len/2;
4043            __m += __delta;
4044            __delta /= 2;
4045            __n_swaps = _VSTD::__sort5<_Compare>(__first, __first + __delta, __m, __m+__delta, __lm1, __comp);
4046        }
4047        else
4048        {
4049            __delta = __len/2;
4050            __m += __delta;
4051            __n_swaps = _VSTD::__sort3<_Compare>(__first, __m, __lm1, __comp);
4052        }
4053        }
4054        // *__m is median
4055        // partition [__first, __m) < *__m and *__m <= [__m, __last)
4056        // (this inhibits tossing elements equivalent to __m around unnecessarily)
4057        _RandomAccessIterator __i = __first;
4058        _RandomAccessIterator __j = __lm1;
4059        // j points beyond range to be tested, *__m is known to be <= *__lm1
4060        // The search going up is known to be guarded but the search coming down isn't.
4061        // Prime the downward search with a guard.
4062        if (!__comp(*__i, *__m))  // if *__first == *__m
4063        {
4064            // *__first == *__m, *__first doesn't go in first part
4065            // manually guard downward moving __j against __i
4066            while (true)
4067            {
4068                if (__i == --__j)
4069                {
4070                    // *__first == *__m, *__m <= all other elements
4071                    // Parition instead into [__first, __i) == *__first and *__first < [__i, __last)
4072                    ++__i;  // __first + 1
4073                    __j = __last;
4074                    if (!__comp(*__first, *--__j))  // we need a guard if *__first == *(__last-1)
4075                    {
4076                        while (true)
4077                        {
4078                            if (__i == __j)
4079                                return;  // [__first, __last) all equivalent elements
4080                            if (__comp(*__first, *__i))
4081                            {
4082                                swap(*__i, *__j);
4083                                ++__n_swaps;
4084                                ++__i;
4085                                break;
4086                            }
4087                            ++__i;
4088                        }
4089                    }
4090                    // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
4091                    if (__i == __j)
4092                        return;
4093                    while (true)
4094                    {
4095                        while (!__comp(*__first, *__i))
4096                            ++__i;
4097                        while (__comp(*__first, *--__j))
4098                            ;
4099                        if (__i >= __j)
4100                            break;
4101                        swap(*__i, *__j);
4102                        ++__n_swaps;
4103                        ++__i;
4104                    }
4105                    // [__first, __i) == *__first and *__first < [__i, __last)
4106                    // The first part is sorted, sort the secod part
4107                    // _VSTD::__sort<_Compare>(__i, __last, __comp);
4108                    __first = __i;
4109                    goto __restart;
4110                }
4111                if (__comp(*__j, *__m))
4112                {
4113                    swap(*__i, *__j);
4114                    ++__n_swaps;
4115                    break;  // found guard for downward moving __j, now use unguarded partition
4116                }
4117            }
4118        }
4119        // It is known that *__i < *__m
4120        ++__i;
4121        // j points beyond range to be tested, *__m is known to be <= *__lm1
4122        // if not yet partitioned...
4123        if (__i < __j)
4124        {
4125            // known that *(__i - 1) < *__m
4126            // known that __i <= __m
4127            while (true)
4128            {
4129                // __m still guards upward moving __i
4130                while (__comp(*__i, *__m))
4131                    ++__i;
4132                // It is now known that a guard exists for downward moving __j
4133                while (!__comp(*--__j, *__m))
4134                    ;
4135                if (__i > __j)
4136                    break;
4137                swap(*__i, *__j);
4138                ++__n_swaps;
4139                // It is known that __m != __j
4140                // If __m just moved, follow it
4141                if (__m == __i)
4142                    __m = __j;
4143                ++__i;
4144            }
4145        }
4146        // [__first, __i) < *__m and *__m <= [__i, __last)
4147        if (__i != __m && __comp(*__m, *__i))
4148        {
4149            swap(*__i, *__m);
4150            ++__n_swaps;
4151        }
4152        // [__first, __i) < *__i and *__i <= [__i+1, __last)
4153        // If we were given a perfect partition, see if insertion sort is quick...
4154        if (__n_swaps == 0)
4155        {
4156            bool __fs = _VSTD::__insertion_sort_incomplete<_Compare>(__first, __i, __comp);
4157            if (_VSTD::__insertion_sort_incomplete<_Compare>(__i+1, __last, __comp))
4158            {
4159                if (__fs)
4160                    return;
4161                __last = __i;
4162                continue;
4163            }
4164            else
4165            {
4166                if (__fs)
4167                {
4168                    __first = ++__i;
4169                    continue;
4170                }
4171            }
4172        }
4173        // sort smaller range with recursive call and larger with tail recursion elimination
4174        if (__i - __first < __last - __i)
4175        {
4176            _VSTD::__sort<_Compare>(__first, __i, __comp);
4177            // _VSTD::__sort<_Compare>(__i+1, __last, __comp);
4178            __first = ++__i;
4179        }
4180        else
4181        {
4182            _VSTD::__sort<_Compare>(__i+1, __last, __comp);
4183            // _VSTD::__sort<_Compare>(__first, __i, __comp);
4184            __last = __i;
4185        }
4186    }
4187}
4188
4189// This forwarder keeps the top call and the recursive calls using the same instantiation, forcing a reference _Compare
4190template <class _RandomAccessIterator, class _Compare>
4191inline _LIBCPP_INLINE_VISIBILITY
4192void
4193sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4194{
4195#ifdef _LIBCPP_DEBUG
4196    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4197    __debug_less<_Compare> __c(__comp);
4198    __sort<_Comp_ref>(__first, __last, __c);
4199#else  // _LIBCPP_DEBUG
4200    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4201    __sort<_Comp_ref>(__first, __last, __comp);
4202#endif  // _LIBCPP_DEBUG
4203}
4204
4205template <class _RandomAccessIterator>
4206inline _LIBCPP_INLINE_VISIBILITY
4207void
4208sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
4209{
4210    _VSTD::sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4211}
4212
4213template <class _Tp>
4214inline _LIBCPP_INLINE_VISIBILITY
4215void
4216sort(_Tp** __first, _Tp** __last)
4217{
4218    _VSTD::sort((size_t*)__first, (size_t*)__last, __less<size_t>());
4219}
4220
4221template <class _Tp>
4222inline _LIBCPP_INLINE_VISIBILITY
4223void
4224sort(__wrap_iter<_Tp*> __first, __wrap_iter<_Tp*> __last)
4225{
4226    _VSTD::sort(__first.base(), __last.base());
4227}
4228
4229template <class _Tp, class _Compare>
4230inline _LIBCPP_INLINE_VISIBILITY
4231void
4232sort(__wrap_iter<_Tp*> __first, __wrap_iter<_Tp*> __last, _Compare __comp)
4233{
4234    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4235    _VSTD::sort<_Tp*, _Comp_ref>(__first.base(), __last.base(), __comp);
4236}
4237
4238_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<char>&, char*>(char*, char*, __less<char>&))
4239_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&))
4240_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&))
4241_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&))
4242_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<short>&, short*>(short*, short*, __less<short>&))
4243_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&))
4244_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<int>&, int*>(int*, int*, __less<int>&))
4245_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&))
4246_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long>&, long*>(long*, long*, __less<long>&))
4247_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&))
4248_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long long>&, long long*>(long long*, long long*, __less<long long>&))
4249_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned long long>&, unsigned long long*>(unsigned long long*, unsigned long long*, __less<unsigned long long>&))
4250_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<float>&, float*>(float*, float*, __less<float>&))
4251_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<double>&, double*>(double*, double*, __less<double>&))
4252_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long double>&, long double*>(long double*, long double*, __less<long double>&))
4253
4254_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<char>&, char*>(char*, char*, __less<char>&))
4255_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&))
4256_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&))
4257_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&))
4258_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<short>&, short*>(short*, short*, __less<short>&))
4259_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&))
4260_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<int>&, int*>(int*, int*, __less<int>&))
4261_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&))
4262_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long>&, long*>(long*, long*, __less<long>&))
4263_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&))
4264_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long long>&, long long*>(long long*, long long*, __less<long long>&))
4265_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned long long>&, unsigned long long*>(unsigned long long*, unsigned long long*, __less<unsigned long long>&))
4266_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<float>&, float*>(float*, float*, __less<float>&))
4267_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<double>&, double*>(double*, double*, __less<double>&))
4268_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long double>&, long double*>(long double*, long double*, __less<long double>&))
4269
4270_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS unsigned __sort5<__less<long double>&, long double*>(long double*, long double*, long double*, long double*, long double*, __less<long double>&))
4271
4272// lower_bound
4273
4274template <class _Compare, class _ForwardIterator, class _Tp>
4275_ForwardIterator
4276__lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4277{
4278    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
4279    difference_type __len = _VSTD::distance(__first, __last);
4280    while (__len != 0)
4281    {
4282        difference_type __l2 = __len / 2;
4283        _ForwardIterator __m = __first;
4284        _VSTD::advance(__m, __l2);
4285        if (__comp(*__m, __value_))
4286        {
4287            __first = ++__m;
4288            __len -= __l2 + 1;
4289        }
4290        else
4291            __len = __l2;
4292    }
4293    return __first;
4294}
4295
4296template <class _ForwardIterator, class _Tp, class _Compare>
4297inline _LIBCPP_INLINE_VISIBILITY
4298_ForwardIterator
4299lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4300{
4301#ifdef _LIBCPP_DEBUG
4302    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4303    __debug_less<_Compare> __c(__comp);
4304    return __lower_bound<_Comp_ref>(__first, __last, __value_, __c);
4305#else  // _LIBCPP_DEBUG
4306    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4307    return __lower_bound<_Comp_ref>(__first, __last, __value_, __comp);
4308#endif  // _LIBCPP_DEBUG
4309}
4310
4311template <class _ForwardIterator, class _Tp>
4312inline _LIBCPP_INLINE_VISIBILITY
4313_ForwardIterator
4314lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4315{
4316    return _VSTD::lower_bound(__first, __last, __value_,
4317                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
4318}
4319
4320// upper_bound
4321
4322template <class _Compare, class _ForwardIterator, class _Tp>
4323_ForwardIterator
4324__upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4325{
4326    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
4327    difference_type __len = _VSTD::distance(__first, __last);
4328    while (__len != 0)
4329    {
4330        difference_type __l2 = __len / 2;
4331        _ForwardIterator __m = __first;
4332        _VSTD::advance(__m, __l2);
4333        if (__comp(__value_, *__m))
4334            __len = __l2;
4335        else
4336        {
4337            __first = ++__m;
4338            __len -= __l2 + 1;
4339        }
4340    }
4341    return __first;
4342}
4343
4344template <class _ForwardIterator, class _Tp, class _Compare>
4345inline _LIBCPP_INLINE_VISIBILITY
4346_ForwardIterator
4347upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4348{
4349#ifdef _LIBCPP_DEBUG
4350    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4351    __debug_less<_Compare> __c(__comp);
4352    return __upper_bound<_Comp_ref>(__first, __last, __value_, __c);
4353#else  // _LIBCPP_DEBUG
4354    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4355    return __upper_bound<_Comp_ref>(__first, __last, __value_, __comp);
4356#endif  // _LIBCPP_DEBUG
4357}
4358
4359template <class _ForwardIterator, class _Tp>
4360inline _LIBCPP_INLINE_VISIBILITY
4361_ForwardIterator
4362upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4363{
4364    return _VSTD::upper_bound(__first, __last, __value_,
4365                             __less<_Tp, typename iterator_traits<_ForwardIterator>::value_type>());
4366}
4367
4368// equal_range
4369
4370template <class _Compare, class _ForwardIterator, class _Tp>
4371pair<_ForwardIterator, _ForwardIterator>
4372__equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4373{
4374    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
4375    difference_type __len = _VSTD::distance(__first, __last);
4376    while (__len != 0)
4377    {
4378        difference_type __l2 = __len / 2;
4379        _ForwardIterator __m = __first;
4380        _VSTD::advance(__m, __l2);
4381        if (__comp(*__m, __value_))
4382        {
4383            __first = ++__m;
4384            __len -= __l2 + 1;
4385        }
4386        else if (__comp(__value_, *__m))
4387        {
4388            __last = __m;
4389            __len = __l2;
4390        }
4391        else
4392        {
4393            _ForwardIterator __mp1 = __m;
4394            return pair<_ForwardIterator, _ForwardIterator>
4395                   (
4396                      __lower_bound<_Compare>(__first, __m, __value_, __comp),
4397                      __upper_bound<_Compare>(++__mp1, __last, __value_, __comp)
4398                   );
4399        }
4400    }
4401    return pair<_ForwardIterator, _ForwardIterator>(__first, __first);
4402}
4403
4404template <class _ForwardIterator, class _Tp, class _Compare>
4405inline _LIBCPP_INLINE_VISIBILITY
4406pair<_ForwardIterator, _ForwardIterator>
4407equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4408{
4409#ifdef _LIBCPP_DEBUG
4410    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4411    __debug_less<_Compare> __c(__comp);
4412    return __equal_range<_Comp_ref>(__first, __last, __value_, __c);
4413#else  // _LIBCPP_DEBUG
4414    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4415    return __equal_range<_Comp_ref>(__first, __last, __value_, __comp);
4416#endif  // _LIBCPP_DEBUG
4417}
4418
4419template <class _ForwardIterator, class _Tp>
4420inline _LIBCPP_INLINE_VISIBILITY
4421pair<_ForwardIterator, _ForwardIterator>
4422equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4423{
4424    return _VSTD::equal_range(__first, __last, __value_,
4425                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
4426}
4427
4428// binary_search
4429
4430template <class _Compare, class _ForwardIterator, class _Tp>
4431inline _LIBCPP_INLINE_VISIBILITY
4432bool
4433__binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4434{
4435    __first = __lower_bound<_Compare>(__first, __last, __value_, __comp);
4436    return __first != __last && !__comp(__value_, *__first);
4437}
4438
4439template <class _ForwardIterator, class _Tp, class _Compare>
4440inline _LIBCPP_INLINE_VISIBILITY
4441bool
4442binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4443{
4444#ifdef _LIBCPP_DEBUG
4445    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4446    __debug_less<_Compare> __c(__comp);
4447    return __binary_search<_Comp_ref>(__first, __last, __value_, __c);
4448#else  // _LIBCPP_DEBUG
4449    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4450    return __binary_search<_Comp_ref>(__first, __last, __value_, __comp);
4451#endif  // _LIBCPP_DEBUG
4452}
4453
4454template <class _ForwardIterator, class _Tp>
4455inline _LIBCPP_INLINE_VISIBILITY
4456bool
4457binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4458{
4459    return _VSTD::binary_search(__first, __last, __value_,
4460                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
4461}
4462
4463// merge
4464
4465template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
4466_OutputIterator
4467__merge(_InputIterator1 __first1, _InputIterator1 __last1,
4468        _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
4469{
4470    for (; __first1 != __last1; ++__result)
4471    {
4472        if (__first2 == __last2)
4473            return _VSTD::copy(__first1, __last1, __result);
4474        if (__comp(*__first2, *__first1))
4475        {
4476            *__result = *__first2;
4477            ++__first2;
4478        }
4479        else
4480        {
4481            *__result = *__first1;
4482            ++__first1;
4483        }
4484    }
4485    return _VSTD::copy(__first2, __last2, __result);
4486}
4487
4488template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
4489inline _LIBCPP_INLINE_VISIBILITY
4490_OutputIterator
4491merge(_InputIterator1 __first1, _InputIterator1 __last1,
4492      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
4493{
4494#ifdef _LIBCPP_DEBUG
4495    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4496    __debug_less<_Compare> __c(__comp);
4497    return _VSTD::__merge<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
4498#else  // _LIBCPP_DEBUG
4499    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4500    return _VSTD::__merge<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
4501#endif  // _LIBCPP_DEBUG
4502}
4503
4504template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
4505inline _LIBCPP_INLINE_VISIBILITY
4506_OutputIterator
4507merge(_InputIterator1 __first1, _InputIterator1 __last1,
4508      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
4509{
4510    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
4511    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
4512    return merge(__first1, __last1, __first2, __last2, __result, __less<__v1, __v2>());
4513}
4514
4515// inplace_merge
4516
4517template <class _Compare, class _InputIterator1, class _InputIterator2,
4518          class _OutputIterator>
4519void __half_inplace_merge(_InputIterator1 __first1, _InputIterator1 __last1,
4520                          _InputIterator2 __first2, _InputIterator2 __last2,
4521                          _OutputIterator __result, _Compare __comp)
4522{
4523    for (; __first1 != __last1; ++__result)
4524    {
4525        if (__first2 == __last2)
4526        {
4527            _VSTD::move(__first1, __last1, __result);
4528            return;
4529        }
4530
4531        if (__comp(*__first2, *__first1))
4532        {
4533            *__result = _VSTD::move(*__first2);
4534            ++__first2;
4535        }
4536        else
4537        {
4538            *__result = _VSTD::move(*__first1);
4539            ++__first1;
4540        }
4541    }
4542    // __first2 through __last2 are already in the right spot.
4543}
4544
4545template <class _Compare, class _BidirectionalIterator>
4546void
4547__buffered_inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
4548                _Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
4549                                 typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
4550                typename iterator_traits<_BidirectionalIterator>::value_type* __buff)
4551{
4552    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
4553    __destruct_n __d(0);
4554    unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
4555    if (__len1 <= __len2)
4556    {
4557        value_type* __p = __buff;
4558        for (_BidirectionalIterator __i = __first; __i != __middle; __d.__incr((value_type*)0), (void) ++__i, ++__p)
4559            ::new(__p) value_type(_VSTD::move(*__i));
4560        __half_inplace_merge(__buff, __p, __middle, __last, __first, __comp);
4561    }
4562    else
4563    {
4564        value_type* __p = __buff;
4565        for (_BidirectionalIterator __i = __middle; __i != __last; __d.__incr((value_type*)0), (void) ++__i, ++__p)
4566            ::new(__p) value_type(_VSTD::move(*__i));
4567        typedef reverse_iterator<_BidirectionalIterator> _RBi;
4568        typedef reverse_iterator<value_type*> _Rv;
4569        __half_inplace_merge(_Rv(__p), _Rv(__buff),
4570                             _RBi(__middle), _RBi(__first),
4571                             _RBi(__last), __invert<_Compare>(__comp));
4572    }
4573}
4574
4575template <class _Compare, class _BidirectionalIterator>
4576void
4577__inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
4578                _Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
4579                                 typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
4580                typename iterator_traits<_BidirectionalIterator>::value_type* __buff, ptrdiff_t __buff_size)
4581{
4582    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
4583    while (true)
4584    {
4585        // if __middle == __last, we're done
4586        if (__len2 == 0)
4587            return;
4588        if (__len1 <= __buff_size || __len2 <= __buff_size)
4589            return __buffered_inplace_merge<_Compare>
4590                   (__first, __middle, __last, __comp, __len1, __len2, __buff);
4591        // shrink [__first, __middle) as much as possible (with no moves), returning if it shrinks to 0
4592        for (; true; ++__first, (void) --__len1)
4593        {
4594            if (__len1 == 0)
4595                return;
4596            if (__comp(*__middle, *__first))
4597                break;
4598        }
4599        // __first < __middle < __last
4600        // *__first > *__middle
4601        // partition [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last) such that
4602        //     all elements in:
4603        //         [__first, __m1)  <= [__middle, __m2)
4604        //         [__middle, __m2) <  [__m1, __middle)
4605        //         [__m1, __middle) <= [__m2, __last)
4606        //     and __m1 or __m2 is in the middle of its range
4607        _BidirectionalIterator __m1;  // "median" of [__first, __middle)
4608        _BidirectionalIterator __m2;  // "median" of [__middle, __last)
4609        difference_type __len11;      // distance(__first, __m1)
4610        difference_type __len21;      // distance(__middle, __m2)
4611        // binary search smaller range
4612        if (__len1 < __len2)
4613        {   // __len >= 1, __len2 >= 2
4614            __len21 = __len2 / 2;
4615            __m2 = __middle;
4616            _VSTD::advance(__m2, __len21);
4617            __m1 = __upper_bound<_Compare>(__first, __middle, *__m2, __comp);
4618            __len11 = _VSTD::distance(__first, __m1);
4619        }
4620        else
4621        {
4622            if (__len1 == 1)
4623            {   // __len1 >= __len2 && __len2 > 0, therefore __len2 == 1
4624                // It is known *__first > *__middle
4625                swap(*__first, *__middle);
4626                return;
4627            }
4628            // __len1 >= 2, __len2 >= 1
4629            __len11 = __len1 / 2;
4630            __m1 = __first;
4631            _VSTD::advance(__m1, __len11);
4632            __m2 = __lower_bound<_Compare>(__middle, __last, *__m1, __comp);
4633            __len21 = _VSTD::distance(__middle, __m2);
4634        }
4635        difference_type __len12 = __len1 - __len11;  // distance(__m1, __middle)
4636        difference_type __len22 = __len2 - __len21;  // distance(__m2, __last)
4637        // [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last)
4638        // swap middle two partitions
4639        __middle = _VSTD::rotate(__m1, __middle, __m2);
4640        // __len12 and __len21 now have swapped meanings
4641        // merge smaller range with recurisve call and larger with tail recursion elimination
4642        if (__len11 + __len21 < __len12 + __len22)
4643        {
4644            __inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
4645//          __inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
4646            __first = __middle;
4647            __middle = __m2;
4648            __len1 = __len12;
4649            __len2 = __len22;
4650        }
4651        else
4652        {
4653            __inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
4654//          __inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
4655            __last = __middle;
4656            __middle = __m1;
4657            __len1 = __len11;
4658            __len2 = __len21;
4659        }
4660    }
4661}
4662
4663template <class _BidirectionalIterator, class _Compare>
4664inline _LIBCPP_INLINE_VISIBILITY
4665void
4666inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
4667              _Compare __comp)
4668{
4669    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
4670    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
4671    difference_type __len1 = _VSTD::distance(__first, __middle);
4672    difference_type __len2 = _VSTD::distance(__middle, __last);
4673    difference_type __buf_size = _VSTD::min(__len1, __len2);
4674    pair<value_type*, ptrdiff_t> __buf = _VSTD::get_temporary_buffer<value_type>(__buf_size);
4675    unique_ptr<value_type, __return_temporary_buffer> __h(__buf.first);
4676
4677#ifdef _LIBCPP_DEBUG
4678    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4679    __debug_less<_Compare> __c(__comp);
4680    return _VSTD::__inplace_merge<_Comp_ref>(__first, __middle, __last, __c, __len1, __len2,
4681                                            __buf.first, __buf.second);
4682#else  // _LIBCPP_DEBUG
4683    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4684    return _VSTD::__inplace_merge<_Comp_ref>(__first, __middle, __last, __comp, __len1, __len2,
4685                                            __buf.first, __buf.second);
4686#endif  // _LIBCPP_DEBUG
4687}
4688
4689template <class _BidirectionalIterator>
4690inline _LIBCPP_INLINE_VISIBILITY
4691void
4692inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last)
4693{
4694    _VSTD::inplace_merge(__first, __middle, __last,
4695                        __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
4696}
4697
4698// stable_sort
4699
4700template <class _Compare, class _InputIterator1, class _InputIterator2>
4701void
4702__merge_move_construct(_InputIterator1 __first1, _InputIterator1 __last1,
4703        _InputIterator2 __first2, _InputIterator2 __last2,
4704        typename iterator_traits<_InputIterator1>::value_type* __result, _Compare __comp)
4705{
4706    typedef typename iterator_traits<_InputIterator1>::value_type value_type;
4707    __destruct_n __d(0);
4708    unique_ptr<value_type, __destruct_n&> __h(__result, __d);
4709    for (; true; ++__result)
4710    {
4711        if (__first1 == __last1)
4712        {
4713            for (; __first2 != __last2; ++__first2, ++__result, __d.__incr((value_type*)0))
4714                ::new (__result) value_type(_VSTD::move(*__first2));
4715            __h.release();
4716            return;
4717        }
4718        if (__first2 == __last2)
4719        {
4720            for (; __first1 != __last1; ++__first1, ++__result, __d.__incr((value_type*)0))
4721                ::new (__result) value_type(_VSTD::move(*__first1));
4722            __h.release();
4723            return;
4724        }
4725        if (__comp(*__first2, *__first1))
4726        {
4727            ::new (__result) value_type(_VSTD::move(*__first2));
4728            __d.__incr((value_type*)0);
4729            ++__first2;
4730        }
4731        else
4732        {
4733            ::new (__result) value_type(_VSTD::move(*__first1));
4734            __d.__incr((value_type*)0);
4735            ++__first1;
4736        }
4737    }
4738}
4739
4740template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
4741void
4742__merge_move_assign(_InputIterator1 __first1, _InputIterator1 __last1,
4743        _InputIterator2 __first2, _InputIterator2 __last2,
4744        _OutputIterator __result, _Compare __comp)
4745{
4746    for (; __first1 != __last1; ++__result)
4747    {
4748        if (__first2 == __last2)
4749        {
4750            for (; __first1 != __last1; ++__first1, ++__result)
4751                *__result = _VSTD::move(*__first1);
4752            return;
4753        }
4754        if (__comp(*__first2, *__first1))
4755        {
4756            *__result = _VSTD::move(*__first2);
4757            ++__first2;
4758        }
4759        else
4760        {
4761            *__result = _VSTD::move(*__first1);
4762            ++__first1;
4763        }
4764    }
4765    for (; __first2 != __last2; ++__first2, ++__result)
4766        *__result = _VSTD::move(*__first2);
4767}
4768
4769template <class _Compare, class _RandomAccessIterator>
4770void
4771__stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4772              typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4773              typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size);
4774
4775template <class _Compare, class _RandomAccessIterator>
4776void
4777__stable_sort_move(_RandomAccessIterator __first1, _RandomAccessIterator __last1, _Compare __comp,
4778                   typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4779                   typename iterator_traits<_RandomAccessIterator>::value_type* __first2)
4780{
4781    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4782    switch (__len)
4783    {
4784    case 0:
4785        return;
4786    case 1:
4787        ::new(__first2) value_type(_VSTD::move(*__first1));
4788        return;
4789    case 2:
4790       __destruct_n __d(0);
4791        unique_ptr<value_type, __destruct_n&> __h2(__first2, __d);
4792         if (__comp(*--__last1, *__first1))
4793        {
4794            ::new(__first2) value_type(_VSTD::move(*__last1));
4795            __d.__incr((value_type*)0);
4796            ++__first2;
4797            ::new(__first2) value_type(_VSTD::move(*__first1));
4798        }
4799        else
4800        {
4801            ::new(__first2) value_type(_VSTD::move(*__first1));
4802            __d.__incr((value_type*)0);
4803            ++__first2;
4804            ::new(__first2) value_type(_VSTD::move(*__last1));
4805        }
4806        __h2.release();
4807        return;
4808    }
4809    if (__len <= 8)
4810    {
4811        __insertion_sort_move<_Compare>(__first1, __last1, __first2, __comp);
4812        return;
4813    }
4814    typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
4815    _RandomAccessIterator __m = __first1 + __l2;
4816    __stable_sort<_Compare>(__first1, __m, __comp, __l2, __first2, __l2);
4817    __stable_sort<_Compare>(__m, __last1, __comp, __len - __l2, __first2 + __l2, __len - __l2);
4818    __merge_move_construct<_Compare>(__first1, __m, __m, __last1, __first2, __comp);
4819}
4820
4821template <class _Tp>
4822struct __stable_sort_switch
4823{
4824    static const unsigned value = 128*is_trivially_copy_assignable<_Tp>::value;
4825};
4826
4827template <class _Compare, class _RandomAccessIterator>
4828void
4829__stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4830              typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4831              typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size)
4832{
4833    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4834    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4835    switch (__len)
4836    {
4837    case 0:
4838    case 1:
4839        return;
4840    case 2:
4841        if (__comp(*--__last, *__first))
4842            swap(*__first, *__last);
4843        return;
4844    }
4845    if (__len <= static_cast<difference_type>(__stable_sort_switch<value_type>::value))
4846    {
4847        __insertion_sort<_Compare>(__first, __last, __comp);
4848        return;
4849    }
4850    typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
4851    _RandomAccessIterator __m = __first + __l2;
4852    if (__len <= __buff_size)
4853    {
4854        __destruct_n __d(0);
4855        unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
4856        __stable_sort_move<_Compare>(__first, __m, __comp, __l2, __buff);
4857        __d.__set(__l2, (value_type*)0);
4858        __stable_sort_move<_Compare>(__m, __last, __comp, __len - __l2, __buff + __l2);
4859        __d.__set(__len, (value_type*)0);
4860        __merge_move_assign<_Compare>(__buff, __buff + __l2, __buff + __l2, __buff + __len, __first, __comp);
4861//         __merge<_Compare>(move_iterator<value_type*>(__buff),
4862//                           move_iterator<value_type*>(__buff + __l2),
4863//                           move_iterator<_RandomAccessIterator>(__buff + __l2),
4864//                           move_iterator<_RandomAccessIterator>(__buff + __len),
4865//                           __first, __comp);
4866        return;
4867    }
4868    __stable_sort<_Compare>(__first, __m, __comp, __l2, __buff, __buff_size);
4869    __stable_sort<_Compare>(__m, __last, __comp, __len - __l2, __buff, __buff_size);
4870    __inplace_merge<_Compare>(__first, __m, __last, __comp, __l2, __len - __l2, __buff, __buff_size);
4871}
4872
4873template <class _RandomAccessIterator, class _Compare>
4874inline _LIBCPP_INLINE_VISIBILITY
4875void
4876stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4877{
4878    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4879    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4880    difference_type __len = __last - __first;
4881    pair<value_type*, ptrdiff_t> __buf(0, 0);
4882    unique_ptr<value_type, __return_temporary_buffer> __h;
4883    if (__len > static_cast<difference_type>(__stable_sort_switch<value_type>::value))
4884    {
4885        __buf = _VSTD::get_temporary_buffer<value_type>(__len);
4886        __h.reset(__buf.first);
4887    }
4888#ifdef _LIBCPP_DEBUG
4889    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4890    __debug_less<_Compare> __c(__comp);
4891    __stable_sort<_Comp_ref>(__first, __last, __c, __len, __buf.first, __buf.second);
4892#else  // _LIBCPP_DEBUG
4893    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4894    __stable_sort<_Comp_ref>(__first, __last, __comp, __len, __buf.first, __buf.second);
4895#endif  // _LIBCPP_DEBUG
4896}
4897
4898template <class _RandomAccessIterator>
4899inline _LIBCPP_INLINE_VISIBILITY
4900void
4901stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
4902{
4903    _VSTD::stable_sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4904}
4905
4906// is_heap_until
4907
4908template <class _RandomAccessIterator, class _Compare>
4909_RandomAccessIterator
4910is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4911{
4912    typedef typename _VSTD::iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4913    difference_type __len = __last - __first;
4914    difference_type __p = 0;
4915    difference_type __c = 1;
4916    _RandomAccessIterator __pp = __first;
4917    while (__c < __len)
4918    {
4919        _RandomAccessIterator __cp = __first + __c;
4920        if (__comp(*__pp, *__cp))
4921            return __cp;
4922        ++__c;
4923        ++__cp;
4924        if (__c == __len)
4925            return __last;
4926        if (__comp(*__pp, *__cp))
4927            return __cp;
4928        ++__p;
4929        ++__pp;
4930        __c = 2 * __p + 1;
4931    }
4932    return __last;
4933}
4934
4935template<class _RandomAccessIterator>
4936inline _LIBCPP_INLINE_VISIBILITY
4937_RandomAccessIterator
4938is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last)
4939{
4940    return _VSTD::is_heap_until(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4941}
4942
4943// is_heap
4944
4945template <class _RandomAccessIterator, class _Compare>
4946inline _LIBCPP_INLINE_VISIBILITY
4947bool
4948is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4949{
4950    return _VSTD::is_heap_until(__first, __last, __comp) == __last;
4951}
4952
4953template<class _RandomAccessIterator>
4954inline _LIBCPP_INLINE_VISIBILITY
4955bool
4956is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
4957{
4958    return _VSTD::is_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4959}
4960
4961// push_heap
4962
4963template <class _Compare, class _RandomAccessIterator>
4964void
4965__sift_up(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4966          typename iterator_traits<_RandomAccessIterator>::difference_type __len)
4967{
4968    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4969    if (__len > 1)
4970    {
4971        __len = (__len - 2) / 2;
4972        _RandomAccessIterator __ptr = __first + __len;
4973        if (__comp(*__ptr, *--__last))
4974        {
4975            value_type __t(_VSTD::move(*__last));
4976            do
4977            {
4978                *__last = _VSTD::move(*__ptr);
4979                __last = __ptr;
4980                if (__len == 0)
4981                    break;
4982                __len = (__len - 1) / 2;
4983                __ptr = __first + __len;
4984            } while (__comp(*__ptr, __t));
4985            *__last = _VSTD::move(__t);
4986        }
4987    }
4988}
4989
4990template <class _RandomAccessIterator, class _Compare>
4991inline _LIBCPP_INLINE_VISIBILITY
4992void
4993push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4994{
4995#ifdef _LIBCPP_DEBUG
4996    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4997    __debug_less<_Compare> __c(__comp);
4998    __sift_up<_Comp_ref>(__first, __last, __c, __last - __first);
4999#else  // _LIBCPP_DEBUG
5000    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5001    __sift_up<_Comp_ref>(__first, __last, __comp, __last - __first);
5002#endif  // _LIBCPP_DEBUG
5003}
5004
5005template <class _RandomAccessIterator>
5006inline _LIBCPP_INLINE_VISIBILITY
5007void
5008push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
5009{
5010    _VSTD::push_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5011}
5012
5013// pop_heap
5014
5015template <class _Compare, class _RandomAccessIterator>
5016void
5017__sift_down(_RandomAccessIterator __first, _RandomAccessIterator /*__last*/,
5018            _Compare __comp,
5019            typename iterator_traits<_RandomAccessIterator>::difference_type __len,
5020            _RandomAccessIterator __start)
5021{
5022    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
5023    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
5024    // left-child of __start is at 2 * __start + 1
5025    // right-child of __start is at 2 * __start + 2
5026    difference_type __child = __start - __first;
5027
5028    if (__len < 2 || (__len - 2) / 2 < __child)
5029        return;
5030
5031    __child = 2 * __child + 1;
5032    _RandomAccessIterator __child_i = __first + __child;
5033
5034    if ((__child + 1) < __len && __comp(*__child_i, *(__child_i + 1))) {
5035        // right-child exists and is greater than left-child
5036        ++__child_i;
5037        ++__child;
5038    }
5039
5040    // check if we are in heap-order
5041    if (__comp(*__child_i, *__start))
5042        // we are, __start is larger than it's largest child
5043        return;
5044
5045    value_type __top(_VSTD::move(*__start));
5046    do
5047    {
5048        // we are not in heap-order, swap the parent with it's largest child
5049        *__start = _VSTD::move(*__child_i);
5050        __start = __child_i;
5051
5052        if ((__len - 2) / 2 < __child)
5053            break;
5054
5055        // recompute the child based off of the updated parent
5056        __child = 2 * __child + 1;
5057        __child_i = __first + __child;
5058
5059        if ((__child + 1) < __len && __comp(*__child_i, *(__child_i + 1))) {
5060            // right-child exists and is greater than left-child
5061            ++__child_i;
5062            ++__child;
5063        }
5064
5065        // check if we are in heap-order
5066    } while (!__comp(*__child_i, __top));
5067    *__start = _VSTD::move(__top);
5068}
5069
5070template <class _Compare, class _RandomAccessIterator>
5071inline _LIBCPP_INLINE_VISIBILITY
5072void
5073__pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
5074           typename iterator_traits<_RandomAccessIterator>::difference_type __len)
5075{
5076    if (__len > 1)
5077    {
5078        swap(*__first, *--__last);
5079        __sift_down<_Compare>(__first, __last, __comp, __len - 1, __first);
5080    }
5081}
5082
5083template <class _RandomAccessIterator, class _Compare>
5084inline _LIBCPP_INLINE_VISIBILITY
5085void
5086pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
5087{
5088#ifdef _LIBCPP_DEBUG
5089    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5090    __debug_less<_Compare> __c(__comp);
5091    __pop_heap<_Comp_ref>(__first, __last, __c, __last - __first);
5092#else  // _LIBCPP_DEBUG
5093    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5094    __pop_heap<_Comp_ref>(__first, __last, __comp, __last - __first);
5095#endif  // _LIBCPP_DEBUG
5096}
5097
5098template <class _RandomAccessIterator>
5099inline _LIBCPP_INLINE_VISIBILITY
5100void
5101pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
5102{
5103    _VSTD::pop_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5104}
5105
5106// make_heap
5107
5108template <class _Compare, class _RandomAccessIterator>
5109void
5110__make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
5111{
5112    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
5113    difference_type __n = __last - __first;
5114    if (__n > 1)
5115    {
5116        // start from the first parent, there is no need to consider children
5117        for (difference_type __start = (__n - 2) / 2; __start >= 0; --__start)
5118        {
5119            __sift_down<_Compare>(__first, __last, __comp, __n, __first + __start);
5120        }
5121    }
5122}
5123
5124template <class _RandomAccessIterator, class _Compare>
5125inline _LIBCPP_INLINE_VISIBILITY
5126void
5127make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
5128{
5129#ifdef _LIBCPP_DEBUG
5130    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5131    __debug_less<_Compare> __c(__comp);
5132    __make_heap<_Comp_ref>(__first, __last, __c);
5133#else  // _LIBCPP_DEBUG
5134    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5135    __make_heap<_Comp_ref>(__first, __last, __comp);
5136#endif  // _LIBCPP_DEBUG
5137}
5138
5139template <class _RandomAccessIterator>
5140inline _LIBCPP_INLINE_VISIBILITY
5141void
5142make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
5143{
5144    _VSTD::make_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5145}
5146
5147// sort_heap
5148
5149template <class _Compare, class _RandomAccessIterator>
5150void
5151__sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
5152{
5153    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
5154    for (difference_type __n = __last - __first; __n > 1; --__last, --__n)
5155        __pop_heap<_Compare>(__first, __last, __comp, __n);
5156}
5157
5158template <class _RandomAccessIterator, class _Compare>
5159inline _LIBCPP_INLINE_VISIBILITY
5160void
5161sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
5162{
5163#ifdef _LIBCPP_DEBUG
5164    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5165    __debug_less<_Compare> __c(__comp);
5166    __sort_heap<_Comp_ref>(__first, __last, __c);
5167#else  // _LIBCPP_DEBUG
5168    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5169    __sort_heap<_Comp_ref>(__first, __last, __comp);
5170#endif  // _LIBCPP_DEBUG
5171}
5172
5173template <class _RandomAccessIterator>
5174inline _LIBCPP_INLINE_VISIBILITY
5175void
5176sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
5177{
5178    _VSTD::sort_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5179}
5180
5181// partial_sort
5182
5183template <class _Compare, class _RandomAccessIterator>
5184void
5185__partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
5186             _Compare __comp)
5187{
5188    __make_heap<_Compare>(__first, __middle, __comp);
5189    typename iterator_traits<_RandomAccessIterator>::difference_type __len = __middle - __first;
5190    for (_RandomAccessIterator __i = __middle; __i != __last; ++__i)
5191    {
5192        if (__comp(*__i, *__first))
5193        {
5194            swap(*__i, *__first);
5195            __sift_down<_Compare>(__first, __middle, __comp, __len, __first);
5196        }
5197    }
5198    __sort_heap<_Compare>(__first, __middle, __comp);
5199}
5200
5201template <class _RandomAccessIterator, class _Compare>
5202inline _LIBCPP_INLINE_VISIBILITY
5203void
5204partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
5205             _Compare __comp)
5206{
5207#ifdef _LIBCPP_DEBUG
5208    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5209    __debug_less<_Compare> __c(__comp);
5210    __partial_sort<_Comp_ref>(__first, __middle, __last, __c);
5211#else  // _LIBCPP_DEBUG
5212    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5213    __partial_sort<_Comp_ref>(__first, __middle, __last, __comp);
5214#endif  // _LIBCPP_DEBUG
5215}
5216
5217template <class _RandomAccessIterator>
5218inline _LIBCPP_INLINE_VISIBILITY
5219void
5220partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)
5221{
5222    _VSTD::partial_sort(__first, __middle, __last,
5223                       __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5224}
5225
5226// partial_sort_copy
5227
5228template <class _Compare, class _InputIterator, class _RandomAccessIterator>
5229_RandomAccessIterator
5230__partial_sort_copy(_InputIterator __first, _InputIterator __last,
5231                    _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
5232{
5233    _RandomAccessIterator __r = __result_first;
5234    if (__r != __result_last)
5235    {
5236        for (; __first != __last && __r != __result_last; (void) ++__first, ++__r)
5237            *__r = *__first;
5238        __make_heap<_Compare>(__result_first, __r, __comp);
5239        typename iterator_traits<_RandomAccessIterator>::difference_type __len = __r - __result_first;
5240        for (; __first != __last; ++__first)
5241            if (__comp(*__first, *__result_first))
5242            {
5243                *__result_first = *__first;
5244                __sift_down<_Compare>(__result_first, __r, __comp, __len, __result_first);
5245            }
5246        __sort_heap<_Compare>(__result_first, __r, __comp);
5247    }
5248    return __r;
5249}
5250
5251template <class _InputIterator, class _RandomAccessIterator, class _Compare>
5252inline _LIBCPP_INLINE_VISIBILITY
5253_RandomAccessIterator
5254partial_sort_copy(_InputIterator __first, _InputIterator __last,
5255                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
5256{
5257#ifdef _LIBCPP_DEBUG
5258    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5259    __debug_less<_Compare> __c(__comp);
5260    return __partial_sort_copy<_Comp_ref>(__first, __last, __result_first, __result_last, __c);
5261#else  // _LIBCPP_DEBUG
5262    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5263    return __partial_sort_copy<_Comp_ref>(__first, __last, __result_first, __result_last, __comp);
5264#endif  // _LIBCPP_DEBUG
5265}
5266
5267template <class _InputIterator, class _RandomAccessIterator>
5268inline _LIBCPP_INLINE_VISIBILITY
5269_RandomAccessIterator
5270partial_sort_copy(_InputIterator __first, _InputIterator __last,
5271                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last)
5272{
5273    return _VSTD::partial_sort_copy(__first, __last, __result_first, __result_last,
5274                                   __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5275}
5276
5277// nth_element
5278
5279template <class _Compare, class _RandomAccessIterator>
5280void
5281__nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp)
5282{
5283    // _Compare is known to be a reference type
5284    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
5285    const difference_type __limit = 7;
5286    while (true)
5287    {
5288    __restart:
5289        if (__nth == __last)
5290            return;
5291        difference_type __len = __last - __first;
5292        switch (__len)
5293        {
5294        case 0:
5295        case 1:
5296            return;
5297        case 2:
5298            if (__comp(*--__last, *__first))
5299                swap(*__first, *__last);
5300            return;
5301        case 3:
5302            {
5303            _RandomAccessIterator __m = __first;
5304            _VSTD::__sort3<_Compare>(__first, ++__m, --__last, __comp);
5305            return;
5306            }
5307        }
5308        if (__len <= __limit)
5309        {
5310            __selection_sort<_Compare>(__first, __last, __comp);
5311            return;
5312        }
5313        // __len > __limit >= 3
5314        _RandomAccessIterator __m = __first + __len/2;
5315        _RandomAccessIterator __lm1 = __last;
5316        unsigned __n_swaps = _VSTD::__sort3<_Compare>(__first, __m, --__lm1, __comp);
5317        // *__m is median
5318        // partition [__first, __m) < *__m and *__m <= [__m, __last)
5319        // (this inhibits tossing elements equivalent to __m around unnecessarily)
5320        _RandomAccessIterator __i = __first;
5321        _RandomAccessIterator __j = __lm1;
5322        // j points beyond range to be tested, *__lm1 is known to be <= *__m
5323        // The search going up is known to be guarded but the search coming down isn't.
5324        // Prime the downward search with a guard.
5325        if (!__comp(*__i, *__m))  // if *__first == *__m
5326        {
5327            // *__first == *__m, *__first doesn't go in first part
5328            // manually guard downward moving __j against __i
5329            while (true)
5330            {
5331                if (__i == --__j)
5332                {
5333                    // *__first == *__m, *__m <= all other elements
5334                    // Parition instead into [__first, __i) == *__first and *__first < [__i, __last)
5335                    ++__i;  // __first + 1
5336                    __j = __last;
5337                    if (!__comp(*__first, *--__j))  // we need a guard if *__first == *(__last-1)
5338                    {
5339                        while (true)
5340                        {
5341                            if (__i == __j)
5342                                return;  // [__first, __last) all equivalent elements
5343                            if (__comp(*__first, *__i))
5344                            {
5345                                swap(*__i, *__j);
5346                                ++__n_swaps;
5347                                ++__i;
5348                                break;
5349                            }
5350                            ++__i;
5351                        }
5352                    }
5353                    // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
5354                    if (__i == __j)
5355                        return;
5356                    while (true)
5357                    {
5358                        while (!__comp(*__first, *__i))
5359                            ++__i;
5360                        while (__comp(*__first, *--__j))
5361                            ;
5362                        if (__i >= __j)
5363                            break;
5364                        swap(*__i, *__j);
5365                        ++__n_swaps;
5366                        ++__i;
5367                    }
5368                    // [__first, __i) == *__first and *__first < [__i, __last)
5369                    // The first part is sorted,
5370                    if (__nth < __i)
5371                        return;
5372                    // __nth_element the secod part
5373                    // __nth_element<_Compare>(__i, __nth, __last, __comp);
5374                    __first = __i;
5375                    goto __restart;
5376                }
5377                if (__comp(*__j, *__m))
5378                {
5379                    swap(*__i, *__j);
5380                    ++__n_swaps;
5381                    break;  // found guard for downward moving __j, now use unguarded partition
5382                }
5383            }
5384        }
5385        ++__i;
5386        // j points beyond range to be tested, *__lm1 is known to be <= *__m
5387        // if not yet partitioned...
5388        if (__i < __j)
5389        {
5390            // known that *(__i - 1) < *__m
5391            while (true)
5392            {
5393                // __m still guards upward moving __i
5394                while (__comp(*__i, *__m))
5395                    ++__i;
5396                // It is now known that a guard exists for downward moving __j
5397                while (!__comp(*--__j, *__m))
5398                    ;
5399                if (__i >= __j)
5400                    break;
5401                swap(*__i, *__j);
5402                ++__n_swaps;
5403                // It is known that __m != __j
5404                // If __m just moved, follow it
5405                if (__m == __i)
5406                    __m = __j;
5407                ++__i;
5408            }
5409        }
5410        // [__first, __i) < *__m and *__m <= [__i, __last)
5411        if (__i != __m && __comp(*__m, *__i))
5412        {
5413            swap(*__i, *__m);
5414            ++__n_swaps;
5415        }
5416        // [__first, __i) < *__i and *__i <= [__i+1, __last)
5417        if (__nth == __i)
5418            return;
5419        if (__n_swaps == 0)
5420        {
5421            // We were given a perfectly partitioned sequence.  Coincidence?
5422            if (__nth < __i)
5423            {
5424                // Check for [__first, __i) already sorted
5425                __j = __m = __first;
5426                while (++__j != __i)
5427                {
5428                    if (__comp(*__j, *__m))
5429                        // not yet sorted, so sort
5430                        goto not_sorted;
5431                    __m = __j;
5432                }
5433                // [__first, __i) sorted
5434                return;
5435            }
5436            else
5437            {
5438                // Check for [__i, __last) already sorted
5439                __j = __m = __i;
5440                while (++__j != __last)
5441                {
5442                    if (__comp(*__j, *__m))
5443                        // not yet sorted, so sort
5444                        goto not_sorted;
5445                    __m = __j;
5446                }
5447                // [__i, __last) sorted
5448                return;
5449            }
5450        }
5451not_sorted:
5452        // __nth_element on range containing __nth
5453        if (__nth < __i)
5454        {
5455            // __nth_element<_Compare>(__first, __nth, __i, __comp);
5456            __last = __i;
5457        }
5458        else
5459        {
5460            // __nth_element<_Compare>(__i+1, __nth, __last, __comp);
5461            __first = ++__i;
5462        }
5463    }
5464}
5465
5466template <class _RandomAccessIterator, class _Compare>
5467inline _LIBCPP_INLINE_VISIBILITY
5468void
5469nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp)
5470{
5471#ifdef _LIBCPP_DEBUG
5472    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5473    __debug_less<_Compare> __c(__comp);
5474    __nth_element<_Comp_ref>(__first, __nth, __last, __c);
5475#else  // _LIBCPP_DEBUG
5476    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5477    __nth_element<_Comp_ref>(__first, __nth, __last, __comp);
5478#endif  // _LIBCPP_DEBUG
5479}
5480
5481template <class _RandomAccessIterator>
5482inline _LIBCPP_INLINE_VISIBILITY
5483void
5484nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last)
5485{
5486    _VSTD::nth_element(__first, __nth, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5487}
5488
5489// includes
5490
5491template <class _Compare, class _InputIterator1, class _InputIterator2>
5492bool
5493__includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
5494           _Compare __comp)
5495{
5496    for (; __first2 != __last2; ++__first1)
5497    {
5498        if (__first1 == __last1 || __comp(*__first2, *__first1))
5499            return false;
5500        if (!__comp(*__first1, *__first2))
5501            ++__first2;
5502    }
5503    return true;
5504}
5505
5506template <class _InputIterator1, class _InputIterator2, class _Compare>
5507inline _LIBCPP_INLINE_VISIBILITY
5508bool
5509includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
5510         _Compare __comp)
5511{
5512#ifdef _LIBCPP_DEBUG
5513    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5514    __debug_less<_Compare> __c(__comp);
5515    return __includes<_Comp_ref>(__first1, __last1, __first2, __last2, __c);
5516#else  // _LIBCPP_DEBUG
5517    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5518    return __includes<_Comp_ref>(__first1, __last1, __first2, __last2, __comp);
5519#endif  // _LIBCPP_DEBUG
5520}
5521
5522template <class _InputIterator1, class _InputIterator2>
5523inline _LIBCPP_INLINE_VISIBILITY
5524bool
5525includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2)
5526{
5527    return _VSTD::includes(__first1, __last1, __first2, __last2,
5528                          __less<typename iterator_traits<_InputIterator1>::value_type,
5529                                 typename iterator_traits<_InputIterator2>::value_type>());
5530}
5531
5532// set_union
5533
5534template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5535_OutputIterator
5536__set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5537            _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5538{
5539    for (; __first1 != __last1; ++__result)
5540    {
5541        if (__first2 == __last2)
5542            return _VSTD::copy(__first1, __last1, __result);
5543        if (__comp(*__first2, *__first1))
5544        {
5545            *__result = *__first2;
5546            ++__first2;
5547        }
5548        else
5549        {
5550            if (!__comp(*__first1, *__first2))
5551                ++__first2;
5552            *__result = *__first1;
5553            ++__first1;
5554        }
5555    }
5556    return _VSTD::copy(__first2, __last2, __result);
5557}
5558
5559template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5560inline _LIBCPP_INLINE_VISIBILITY
5561_OutputIterator
5562set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5563          _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5564{
5565#ifdef _LIBCPP_DEBUG
5566    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5567    __debug_less<_Compare> __c(__comp);
5568    return __set_union<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5569#else  // _LIBCPP_DEBUG
5570    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5571    return __set_union<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5572#endif  // _LIBCPP_DEBUG
5573}
5574
5575template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5576inline _LIBCPP_INLINE_VISIBILITY
5577_OutputIterator
5578set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5579          _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5580{
5581    return _VSTD::set_union(__first1, __last1, __first2, __last2, __result,
5582                          __less<typename iterator_traits<_InputIterator1>::value_type,
5583                                 typename iterator_traits<_InputIterator2>::value_type>());
5584}
5585
5586// set_intersection
5587
5588template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5589_OutputIterator
5590__set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5591                   _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5592{
5593    while (__first1 != __last1 && __first2 != __last2)
5594    {
5595        if (__comp(*__first1, *__first2))
5596            ++__first1;
5597        else
5598        {
5599            if (!__comp(*__first2, *__first1))
5600            {
5601                *__result = *__first1;
5602                ++__result;
5603                ++__first1;
5604            }
5605            ++__first2;
5606        }
5607    }
5608    return __result;
5609}
5610
5611template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5612inline _LIBCPP_INLINE_VISIBILITY
5613_OutputIterator
5614set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5615                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5616{
5617#ifdef _LIBCPP_DEBUG
5618    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5619    __debug_less<_Compare> __c(__comp);
5620    return __set_intersection<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5621#else  // _LIBCPP_DEBUG
5622    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5623    return __set_intersection<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5624#endif  // _LIBCPP_DEBUG
5625}
5626
5627template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5628inline _LIBCPP_INLINE_VISIBILITY
5629_OutputIterator
5630set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5631                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5632{
5633    return _VSTD::set_intersection(__first1, __last1, __first2, __last2, __result,
5634                                  __less<typename iterator_traits<_InputIterator1>::value_type,
5635                                         typename iterator_traits<_InputIterator2>::value_type>());
5636}
5637
5638// set_difference
5639
5640template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5641_OutputIterator
5642__set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5643                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5644{
5645    while (__first1 != __last1)
5646    {
5647        if (__first2 == __last2)
5648            return _VSTD::copy(__first1, __last1, __result);
5649        if (__comp(*__first1, *__first2))
5650        {
5651            *__result = *__first1;
5652            ++__result;
5653            ++__first1;
5654        }
5655        else
5656        {
5657            if (!__comp(*__first2, *__first1))
5658                ++__first1;
5659            ++__first2;
5660        }
5661    }
5662    return __result;
5663}
5664
5665template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5666inline _LIBCPP_INLINE_VISIBILITY
5667_OutputIterator
5668set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5669               _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5670{
5671#ifdef _LIBCPP_DEBUG
5672    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5673    __debug_less<_Compare> __c(__comp);
5674    return __set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5675#else  // _LIBCPP_DEBUG
5676    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5677    return __set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5678#endif  // _LIBCPP_DEBUG
5679}
5680
5681template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5682inline _LIBCPP_INLINE_VISIBILITY
5683_OutputIterator
5684set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5685               _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5686{
5687    return _VSTD::set_difference(__first1, __last1, __first2, __last2, __result,
5688                                __less<typename iterator_traits<_InputIterator1>::value_type,
5689                                       typename iterator_traits<_InputIterator2>::value_type>());
5690}
5691
5692// set_symmetric_difference
5693
5694template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5695_OutputIterator
5696__set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5697                           _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5698{
5699    while (__first1 != __last1)
5700    {
5701        if (__first2 == __last2)
5702            return _VSTD::copy(__first1, __last1, __result);
5703        if (__comp(*__first1, *__first2))
5704        {
5705            *__result = *__first1;
5706            ++__result;
5707            ++__first1;
5708        }
5709        else
5710        {
5711            if (__comp(*__first2, *__first1))
5712            {
5713                *__result = *__first2;
5714                ++__result;
5715            }
5716            else
5717                ++__first1;
5718            ++__first2;
5719        }
5720    }
5721    return _VSTD::copy(__first2, __last2, __result);
5722}
5723
5724template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5725inline _LIBCPP_INLINE_VISIBILITY
5726_OutputIterator
5727set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5728                         _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5729{
5730#ifdef _LIBCPP_DEBUG
5731    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5732    __debug_less<_Compare> __c(__comp);
5733    return __set_symmetric_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5734#else  // _LIBCPP_DEBUG
5735    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5736    return __set_symmetric_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5737#endif  // _LIBCPP_DEBUG
5738}
5739
5740template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5741inline _LIBCPP_INLINE_VISIBILITY
5742_OutputIterator
5743set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5744                         _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5745{
5746    return _VSTD::set_symmetric_difference(__first1, __last1, __first2, __last2, __result,
5747                                          __less<typename iterator_traits<_InputIterator1>::value_type,
5748                                                 typename iterator_traits<_InputIterator2>::value_type>());
5749}
5750
5751// lexicographical_compare
5752
5753template <class _Compare, class _InputIterator1, class _InputIterator2>
5754bool
5755__lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
5756                          _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
5757{
5758    for (; __first2 != __last2; ++__first1, (void) ++__first2)
5759    {
5760        if (__first1 == __last1 || __comp(*__first1, *__first2))
5761            return true;
5762        if (__comp(*__first2, *__first1))
5763            return false;
5764    }
5765    return false;
5766}
5767
5768template <class _InputIterator1, class _InputIterator2, class _Compare>
5769inline _LIBCPP_INLINE_VISIBILITY
5770bool
5771lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
5772                        _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
5773{
5774#ifdef _LIBCPP_DEBUG
5775    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5776    __debug_less<_Compare> __c(__comp);
5777    return __lexicographical_compare<_Comp_ref>(__first1, __last1, __first2, __last2, __c);
5778#else  // _LIBCPP_DEBUG
5779    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5780    return __lexicographical_compare<_Comp_ref>(__first1, __last1, __first2, __last2, __comp);
5781#endif  // _LIBCPP_DEBUG
5782}
5783
5784template <class _InputIterator1, class _InputIterator2>
5785inline _LIBCPP_INLINE_VISIBILITY
5786bool
5787lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
5788                        _InputIterator2 __first2, _InputIterator2 __last2)
5789{
5790    return _VSTD::lexicographical_compare(__first1, __last1, __first2, __last2,
5791                                         __less<typename iterator_traits<_InputIterator1>::value_type,
5792                                                typename iterator_traits<_InputIterator2>::value_type>());
5793}
5794
5795// next_permutation
5796
5797template <class _Compare, class _BidirectionalIterator>
5798bool
5799__next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5800{
5801    _BidirectionalIterator __i = __last;
5802    if (__first == __last || __first == --__i)
5803        return false;
5804    while (true)
5805    {
5806        _BidirectionalIterator __ip1 = __i;
5807        if (__comp(*--__i, *__ip1))
5808        {
5809            _BidirectionalIterator __j = __last;
5810            while (!__comp(*__i, *--__j))
5811                ;
5812            swap(*__i, *__j);
5813            _VSTD::reverse(__ip1, __last);
5814            return true;
5815        }
5816        if (__i == __first)
5817        {
5818            _VSTD::reverse(__first, __last);
5819            return false;
5820        }
5821    }
5822}
5823
5824template <class _BidirectionalIterator, class _Compare>
5825inline _LIBCPP_INLINE_VISIBILITY
5826bool
5827next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5828{
5829#ifdef _LIBCPP_DEBUG
5830    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5831    __debug_less<_Compare> __c(__comp);
5832    return __next_permutation<_Comp_ref>(__first, __last, __c);
5833#else  // _LIBCPP_DEBUG
5834    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5835    return __next_permutation<_Comp_ref>(__first, __last, __comp);
5836#endif  // _LIBCPP_DEBUG
5837}
5838
5839template <class _BidirectionalIterator>
5840inline _LIBCPP_INLINE_VISIBILITY
5841bool
5842next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
5843{
5844    return _VSTD::next_permutation(__first, __last,
5845                                  __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
5846}
5847
5848// prev_permutation
5849
5850template <class _Compare, class _BidirectionalIterator>
5851bool
5852__prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5853{
5854    _BidirectionalIterator __i = __last;
5855    if (__first == __last || __first == --__i)
5856        return false;
5857    while (true)
5858    {
5859        _BidirectionalIterator __ip1 = __i;
5860        if (__comp(*__ip1, *--__i))
5861        {
5862            _BidirectionalIterator __j = __last;
5863            while (!__comp(*--__j, *__i))
5864                ;
5865            swap(*__i, *__j);
5866            _VSTD::reverse(__ip1, __last);
5867            return true;
5868        }
5869        if (__i == __first)
5870        {
5871            _VSTD::reverse(__first, __last);
5872            return false;
5873        }
5874    }
5875}
5876
5877template <class _BidirectionalIterator, class _Compare>
5878inline _LIBCPP_INLINE_VISIBILITY
5879bool
5880prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5881{
5882#ifdef _LIBCPP_DEBUG
5883    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5884    __debug_less<_Compare> __c(__comp);
5885    return __prev_permutation<_Comp_ref>(__first, __last, __c);
5886#else  // _LIBCPP_DEBUG
5887    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5888    return __prev_permutation<_Comp_ref>(__first, __last, __comp);
5889#endif  // _LIBCPP_DEBUG
5890}
5891
5892template <class _BidirectionalIterator>
5893inline _LIBCPP_INLINE_VISIBILITY
5894bool
5895prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
5896{
5897    return _VSTD::prev_permutation(__first, __last,
5898                                  __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
5899}
5900
5901_LIBCPP_END_NAMESPACE_STD
5902
5903_LIBCPP_POP_MACROS
5904
5905#endif  // _LIBCPP_ALGORITHM
5906