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 <__undef_min_max>
655
656#include <__debug>
657
658#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
659#pragma GCC system_header
660#endif
661
662_LIBCPP_BEGIN_NAMESPACE_STD
663
664// I'd like to replace these with _VSTD::equal_to<void>, but can't because:
665//   * That only works with C++14 and later, and
666//   * We haven't included <functional> here.
667template <class _T1, class _T2 = _T1>
668struct __equal_to
669{
670    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
671    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T2& __y) const {return __x == __y;}
672    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T2& __x, const _T1& __y) const {return __x == __y;}
673    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T2& __x, const _T2& __y) const {return __x == __y;}
674};
675
676template <class _T1>
677struct __equal_to<_T1, _T1>
678{
679    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
680    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
681};
682
683template <class _T1>
684struct __equal_to<const _T1, _T1>
685{
686    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
687    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
688};
689
690template <class _T1>
691struct __equal_to<_T1, const _T1>
692{
693    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
694    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
695};
696
697template <class _T1, class _T2 = _T1>
698struct __less
699{
700    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
701    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
702
703    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
704    bool operator()(const _T1& __x, const _T2& __y) const {return __x < __y;}
705
706    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
707    bool operator()(const _T2& __x, const _T1& __y) const {return __x < __y;}
708
709    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
710    bool operator()(const _T2& __x, const _T2& __y) const {return __x < __y;}
711};
712
713template <class _T1>
714struct __less<_T1, _T1>
715{
716    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
717    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
718};
719
720template <class _T1>
721struct __less<const _T1, _T1>
722{
723    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
724    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
725};
726
727template <class _T1>
728struct __less<_T1, const _T1>
729{
730    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
731    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
732};
733
734template <class _Predicate>
735class __negate
736{
737private:
738    _Predicate __p_;
739public:
740    _LIBCPP_INLINE_VISIBILITY __negate() {}
741
742    _LIBCPP_INLINE_VISIBILITY
743    explicit __negate(_Predicate __p) : __p_(__p) {}
744
745    template <class _T1>
746    _LIBCPP_INLINE_VISIBILITY
747    bool operator()(const _T1& __x) {return !__p_(__x);}
748
749    template <class _T1, class _T2>
750    _LIBCPP_INLINE_VISIBILITY
751    bool operator()(const _T1& __x, const _T2& __y) {return !__p_(__x, __y);}
752};
753
754#ifdef _LIBCPP_DEBUG
755
756template <class _Compare>
757struct __debug_less
758{
759    _Compare __comp_;
760    __debug_less(_Compare& __c) : __comp_(__c) {}
761
762    template <class _Tp, class _Up>
763    bool operator()(const _Tp& __x, const _Up& __y)
764    {
765        bool __r = __comp_(__x, __y);
766        if (__r)
767            __do_compare_assert(0, __y, __x);
768        return __r;
769    }
770
771    template <class _LHS, class _RHS>
772    inline _LIBCPP_INLINE_VISIBILITY
773    decltype((void)_VSTD::declval<_Compare&>()(
774        _VSTD::declval<_LHS const&>(), _VSTD::declval<_RHS const&>()))
775    __do_compare_assert(int, _LHS const& __l, _RHS const& __r) {
776        _LIBCPP_ASSERT(!__comp_(__l, __r),
777            "Comparator does not induce a strict weak ordering");
778    }
779
780    template <class _LHS, class _RHS>
781    inline _LIBCPP_INLINE_VISIBILITY
782    void __do_compare_assert(long, _LHS const&, _RHS const&) {}
783};
784
785#endif  // _LIBCPP_DEBUG
786
787// Precondition:  __x != 0
788inline _LIBCPP_INLINE_VISIBILITY
789unsigned __ctz(unsigned __x) {
790#ifndef _LIBCPP_COMPILER_MSVC
791    return static_cast<unsigned>(__builtin_ctz(__x));
792#else
793  static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
794  static_assert(sizeof(unsigned long) == 4, "");
795  unsigned long where;
796  // Search from LSB to MSB for first set bit.
797  // Returns zero if no set bit is found.
798  if (_BitScanForward(&where, mask))
799    return where;
800  return 32;
801#endif
802}
803
804inline _LIBCPP_INLINE_VISIBILITY
805unsigned long __ctz(unsigned long __x) {
806#ifndef _LIBCPP_COMPILER_MSVC
807    return static_cast<unsigned long>(__builtin_ctzl(__x));
808#else
809    static_assert(sizeof(unsigned long) == sizeof(unsigned), "");
810    return __ctz(static_cast<unsigned>(__x));
811#endif
812}
813
814inline _LIBCPP_INLINE_VISIBILITY
815unsigned long long __ctz(unsigned long long __x) {
816#ifndef _LIBCPP_COMPILER_MSVC
817    return static_cast<unsigned long long>(__builtin_ctzll(__x));
818#else
819    unsigned long where;
820// Search from LSB to MSB for first set bit.
821// Returns zero if no set bit is found.
822#if defined(_LIBCPP_HAS_BITSCAN64)
823    (defined(_M_AMD64) || defined(__x86_64__))
824  if (_BitScanForward64(&where, mask))
825    return static_cast<int>(where);
826#else
827  // Win32 doesn't have _BitScanForward64 so emulate it with two 32 bit calls.
828  // Scan the Low Word.
829  if (_BitScanForward(&where, static_cast<unsigned long>(mask)))
830    return where;
831  // Scan the High Word.
832  if (_BitScanForward(&where, static_cast<unsigned long>(mask >> 32)))
833    return where + 32; // Create a bit offset from the LSB.
834#endif
835  return 64;
836#endif // _LIBCPP_COMPILER_MSVC
837}
838
839// Precondition:  __x != 0
840inline _LIBCPP_INLINE_VISIBILITY
841unsigned __clz(unsigned __x) {
842#ifndef _LIBCPP_COMPILER_MSVC
843    return static_cast<unsigned>(__builtin_clz(__x));
844#else
845  static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
846  static_assert(sizeof(unsigned long) == 4, "");
847  unsigned long where;
848  // Search from LSB to MSB for first set bit.
849  // Returns zero if no set bit is found.
850  if (_BitScanReverse(&where, mask))
851    return 31 - where;
852  return 32; // Undefined Behavior.
853#endif
854}
855
856inline _LIBCPP_INLINE_VISIBILITY
857unsigned long __clz(unsigned long __x) {
858#ifndef _LIBCPP_COMPILER_MSVC
859    return static_cast<unsigned long>(__builtin_clzl (__x));
860#else
861    static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
862    return __clz(static_cast<unsigned>(__x));
863#endif
864}
865
866inline _LIBCPP_INLINE_VISIBILITY
867unsigned long long __clz(unsigned long long __x) {
868#ifndef _LIBCPP_COMPILER_MSVC
869    return static_cast<unsigned long long>(__builtin_clzll(__x));
870#else
871  unsigned long where;
872// BitScanReverse scans from MSB to LSB for first set bit.
873// Returns 0 if no set bit is found.
874#if defined(_LIBCPP_HAS_BITSCAN64)
875  if (_BitScanReverse64(&where, mask))
876    return static_cast<int>(63 - where);
877#else
878  // Scan the high 32 bits.
879  if (_BitScanReverse(&where, static_cast<unsigned long>(mask >> 32)))
880    return 63 - (where + 32); // Create a bit offset from the MSB.
881  // Scan the low 32 bits.
882  if (_BitScanReverse(&where, static_cast<unsigned long>(mask)))
883    return 63 - where;
884#endif
885  return 64; // Undefined Behavior.
886#endif // _LIBCPP_COMPILER_MSVC
887}
888
889inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned __x) {
890#ifndef _LIBCPP_COMPILER_MSVC
891  return __builtin_popcount  (__x);
892#else
893  static_assert(sizeof(unsigned) == 4, "");
894  return __popcnt(__x);
895#endif
896}
897
898inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned long __x) {
899#ifndef _LIBCPP_COMPILER_MSVC
900  return __builtin_popcountl (__x);
901#else
902  static_assert(sizeof(unsigned long) == 4, "");
903  return __popcnt(__x);
904#endif
905}
906
907inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned long long __x) {
908#ifndef _LIBCPP_COMPILER_MSVC
909  return __builtin_popcountll(__x);
910#else
911  static_assert(sizeof(unsigned long long) == 8, "");
912  return __popcnt64(__x);
913#endif
914}
915
916// all_of
917
918template <class _InputIterator, class _Predicate>
919inline _LIBCPP_INLINE_VISIBILITY
920bool
921all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
922{
923    for (; __first != __last; ++__first)
924        if (!__pred(*__first))
925            return false;
926    return true;
927}
928
929// any_of
930
931template <class _InputIterator, class _Predicate>
932inline _LIBCPP_INLINE_VISIBILITY
933bool
934any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
935{
936    for (; __first != __last; ++__first)
937        if (__pred(*__first))
938            return true;
939    return false;
940}
941
942// none_of
943
944template <class _InputIterator, class _Predicate>
945inline _LIBCPP_INLINE_VISIBILITY
946bool
947none_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
948{
949    for (; __first != __last; ++__first)
950        if (__pred(*__first))
951            return false;
952    return true;
953}
954
955// for_each
956
957template <class _InputIterator, class _Function>
958inline _LIBCPP_INLINE_VISIBILITY
959_Function
960for_each(_InputIterator __first, _InputIterator __last, _Function __f)
961{
962    for (; __first != __last; ++__first)
963        __f(*__first);
964    return __f;
965}
966
967#if _LIBCPP_STD_VER > 14
968// for_each_n
969
970template <class _InputIterator, class _Size, class _Function>
971inline _LIBCPP_INLINE_VISIBILITY
972_InputIterator
973for_each_n(_InputIterator __first, _Size __orig_n, _Function __f)
974{
975    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
976    _IntegralSize __n = __orig_n;
977    while (__n > 0)
978    {
979         __f(*__first);
980         ++__first;
981         --__n;
982    }
983    return __first;
984}
985#endif
986
987// find
988
989template <class _InputIterator, class _Tp>
990inline _LIBCPP_INLINE_VISIBILITY
991_InputIterator
992find(_InputIterator __first, _InputIterator __last, const _Tp& __value_)
993{
994    for (; __first != __last; ++__first)
995        if (*__first == __value_)
996            break;
997    return __first;
998}
999
1000// find_if
1001
1002template <class _InputIterator, class _Predicate>
1003inline _LIBCPP_INLINE_VISIBILITY
1004_InputIterator
1005find_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
1006{
1007    for (; __first != __last; ++__first)
1008        if (__pred(*__first))
1009            break;
1010    return __first;
1011}
1012
1013// find_if_not
1014
1015template<class _InputIterator, class _Predicate>
1016inline _LIBCPP_INLINE_VISIBILITY
1017_InputIterator
1018find_if_not(_InputIterator __first, _InputIterator __last, _Predicate __pred)
1019{
1020    for (; __first != __last; ++__first)
1021        if (!__pred(*__first))
1022            break;
1023    return __first;
1024}
1025
1026// find_end
1027
1028template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
1029_ForwardIterator1
1030__find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1031           _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
1032           forward_iterator_tag, forward_iterator_tag)
1033{
1034    // modeled after search algorithm
1035    _ForwardIterator1 __r = __last1;  // __last1 is the "default" answer
1036    if (__first2 == __last2)
1037        return __r;
1038    while (true)
1039    {
1040        while (true)
1041        {
1042            if (__first1 == __last1)         // if source exhausted return last correct answer
1043                return __r;                  //    (or __last1 if never found)
1044            if (__pred(*__first1, *__first2))
1045                break;
1046            ++__first1;
1047        }
1048        // *__first1 matches *__first2, now match elements after here
1049        _ForwardIterator1 __m1 = __first1;
1050        _ForwardIterator2 __m2 = __first2;
1051        while (true)
1052        {
1053            if (++__m2 == __last2)
1054            {                         // Pattern exhaused, record answer and search for another one
1055                __r = __first1;
1056                ++__first1;
1057                break;
1058            }
1059            if (++__m1 == __last1)     // Source exhausted, return last answer
1060                return __r;
1061            if (!__pred(*__m1, *__m2))  // mismatch, restart with a new __first
1062            {
1063                ++__first1;
1064                break;
1065            }  // else there is a match, check next elements
1066        }
1067    }
1068}
1069
1070template <class _BinaryPredicate, class _BidirectionalIterator1, class _BidirectionalIterator2>
1071_BidirectionalIterator1
1072__find_end(_BidirectionalIterator1 __first1, _BidirectionalIterator1 __last1,
1073           _BidirectionalIterator2 __first2, _BidirectionalIterator2 __last2, _BinaryPredicate __pred,
1074           bidirectional_iterator_tag, bidirectional_iterator_tag)
1075{
1076    // modeled after search algorithm (in reverse)
1077    if (__first2 == __last2)
1078        return __last1;  // Everything matches an empty sequence
1079    _BidirectionalIterator1 __l1 = __last1;
1080    _BidirectionalIterator2 __l2 = __last2;
1081    --__l2;
1082    while (true)
1083    {
1084        // Find last element in sequence 1 that matchs *(__last2-1), with a mininum of loop checks
1085        while (true)
1086        {
1087            if (__first1 == __l1)  // return __last1 if no element matches *__first2
1088                return __last1;
1089            if (__pred(*--__l1, *__l2))
1090                break;
1091        }
1092        // *__l1 matches *__l2, now match elements before here
1093        _BidirectionalIterator1 __m1 = __l1;
1094        _BidirectionalIterator2 __m2 = __l2;
1095        while (true)
1096        {
1097            if (__m2 == __first2)  // If pattern exhausted, __m1 is the answer (works for 1 element pattern)
1098                return __m1;
1099            if (__m1 == __first1)  // Otherwise if source exhaused, pattern not found
1100                return __last1;
1101            if (!__pred(*--__m1, *--__m2))  // if there is a mismatch, restart with a new __l1
1102            {
1103                break;
1104            }  // else there is a match, check next elements
1105        }
1106    }
1107}
1108
1109template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1110_LIBCPP_CONSTEXPR_AFTER_CXX11 _RandomAccessIterator1
1111__find_end(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
1112           _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
1113           random_access_iterator_tag, random_access_iterator_tag)
1114{
1115    // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
1116    typename iterator_traits<_RandomAccessIterator2>::difference_type __len2 = __last2 - __first2;
1117    if (__len2 == 0)
1118        return __last1;
1119    typename iterator_traits<_RandomAccessIterator1>::difference_type __len1 = __last1 - __first1;
1120    if (__len1 < __len2)
1121        return __last1;
1122    const _RandomAccessIterator1 __s = __first1 + (__len2 - 1);  // End of pattern match can't go before here
1123    _RandomAccessIterator1 __l1 = __last1;
1124    _RandomAccessIterator2 __l2 = __last2;
1125    --__l2;
1126    while (true)
1127    {
1128        while (true)
1129        {
1130            if (__s == __l1)
1131                return __last1;
1132            if (__pred(*--__l1, *__l2))
1133                break;
1134        }
1135        _RandomAccessIterator1 __m1 = __l1;
1136        _RandomAccessIterator2 __m2 = __l2;
1137        while (true)
1138        {
1139            if (__m2 == __first2)
1140                return __m1;
1141                                 // no need to check range on __m1 because __s guarantees we have enough source
1142            if (!__pred(*--__m1, *--__m2))
1143            {
1144                break;
1145            }
1146        }
1147    }
1148}
1149
1150template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1151inline _LIBCPP_INLINE_VISIBILITY
1152_ForwardIterator1
1153find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1154         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1155{
1156    return _VSTD::__find_end<typename add_lvalue_reference<_BinaryPredicate>::type>
1157                         (__first1, __last1, __first2, __last2, __pred,
1158                          typename iterator_traits<_ForwardIterator1>::iterator_category(),
1159                          typename iterator_traits<_ForwardIterator2>::iterator_category());
1160}
1161
1162template <class _ForwardIterator1, class _ForwardIterator2>
1163inline _LIBCPP_INLINE_VISIBILITY
1164_ForwardIterator1
1165find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1166         _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1167{
1168    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1169    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1170    return _VSTD::find_end(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1171}
1172
1173// find_first_of
1174
1175template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1176_LIBCPP_CONSTEXPR_AFTER_CXX11 _ForwardIterator1
1177__find_first_of_ce(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1178              _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1179{
1180    for (; __first1 != __last1; ++__first1)
1181        for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
1182            if (__pred(*__first1, *__j))
1183                return __first1;
1184    return __last1;
1185}
1186
1187
1188template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1189inline _LIBCPP_INLINE_VISIBILITY
1190_ForwardIterator1
1191find_first_of(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1192              _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1193{
1194    return _VSTD::__find_first_of_ce(__first1, __last1, __first2, __last2, __pred);
1195}
1196
1197template <class _ForwardIterator1, class _ForwardIterator2>
1198inline _LIBCPP_INLINE_VISIBILITY
1199_ForwardIterator1
1200find_first_of(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1201              _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1202{
1203    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1204    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1205    return _VSTD::__find_first_of_ce(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1206}
1207
1208// adjacent_find
1209
1210template <class _ForwardIterator, class _BinaryPredicate>
1211inline _LIBCPP_INLINE_VISIBILITY
1212_ForwardIterator
1213adjacent_find(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
1214{
1215    if (__first != __last)
1216    {
1217        _ForwardIterator __i = __first;
1218        while (++__i != __last)
1219        {
1220            if (__pred(*__first, *__i))
1221                return __first;
1222            __first = __i;
1223        }
1224    }
1225    return __last;
1226}
1227
1228template <class _ForwardIterator>
1229inline _LIBCPP_INLINE_VISIBILITY
1230_ForwardIterator
1231adjacent_find(_ForwardIterator __first, _ForwardIterator __last)
1232{
1233    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
1234    return _VSTD::adjacent_find(__first, __last, __equal_to<__v>());
1235}
1236
1237// count
1238
1239template <class _InputIterator, class _Tp>
1240inline _LIBCPP_INLINE_VISIBILITY
1241typename iterator_traits<_InputIterator>::difference_type
1242count(_InputIterator __first, _InputIterator __last, const _Tp& __value_)
1243{
1244    typename iterator_traits<_InputIterator>::difference_type __r(0);
1245    for (; __first != __last; ++__first)
1246        if (*__first == __value_)
1247            ++__r;
1248    return __r;
1249}
1250
1251// count_if
1252
1253template <class _InputIterator, class _Predicate>
1254inline _LIBCPP_INLINE_VISIBILITY
1255typename iterator_traits<_InputIterator>::difference_type
1256count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
1257{
1258    typename iterator_traits<_InputIterator>::difference_type __r(0);
1259    for (; __first != __last; ++__first)
1260        if (__pred(*__first))
1261            ++__r;
1262    return __r;
1263}
1264
1265// mismatch
1266
1267template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1268inline _LIBCPP_INLINE_VISIBILITY
1269pair<_InputIterator1, _InputIterator2>
1270mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1271         _InputIterator2 __first2, _BinaryPredicate __pred)
1272{
1273    for (; __first1 != __last1; ++__first1, (void) ++__first2)
1274        if (!__pred(*__first1, *__first2))
1275            break;
1276    return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1277}
1278
1279template <class _InputIterator1, class _InputIterator2>
1280inline _LIBCPP_INLINE_VISIBILITY
1281pair<_InputIterator1, _InputIterator2>
1282mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2)
1283{
1284    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1285    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1286    return _VSTD::mismatch(__first1, __last1, __first2, __equal_to<__v1, __v2>());
1287}
1288
1289#if _LIBCPP_STD_VER > 11
1290template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1291inline _LIBCPP_INLINE_VISIBILITY
1292pair<_InputIterator1, _InputIterator2>
1293mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1294         _InputIterator2 __first2, _InputIterator2 __last2,
1295         _BinaryPredicate __pred)
1296{
1297    for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void) ++__first2)
1298        if (!__pred(*__first1, *__first2))
1299            break;
1300    return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1301}
1302
1303template <class _InputIterator1, class _InputIterator2>
1304inline _LIBCPP_INLINE_VISIBILITY
1305pair<_InputIterator1, _InputIterator2>
1306mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1307         _InputIterator2 __first2, _InputIterator2 __last2)
1308{
1309    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1310    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1311    return _VSTD::mismatch(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1312}
1313#endif
1314
1315// equal
1316
1317template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1318inline _LIBCPP_INLINE_VISIBILITY
1319bool
1320equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate __pred)
1321{
1322    for (; __first1 != __last1; ++__first1, (void) ++__first2)
1323        if (!__pred(*__first1, *__first2))
1324            return false;
1325    return true;
1326}
1327
1328template <class _InputIterator1, class _InputIterator2>
1329inline _LIBCPP_INLINE_VISIBILITY
1330bool
1331equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2)
1332{
1333    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1334    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1335    return _VSTD::equal(__first1, __last1, __first2, __equal_to<__v1, __v2>());
1336}
1337
1338#if _LIBCPP_STD_VER > 11
1339template <class _BinaryPredicate, class _InputIterator1, class _InputIterator2>
1340inline _LIBCPP_INLINE_VISIBILITY
1341bool
1342__equal(_InputIterator1 __first1, _InputIterator1 __last1,
1343        _InputIterator2 __first2, _InputIterator2 __last2, _BinaryPredicate __pred,
1344        input_iterator_tag, input_iterator_tag )
1345{
1346    for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void) ++__first2)
1347        if (!__pred(*__first1, *__first2))
1348            return false;
1349    return __first1 == __last1 && __first2 == __last2;
1350}
1351
1352template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1353inline _LIBCPP_INLINE_VISIBILITY
1354bool
1355__equal(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
1356        _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
1357      random_access_iterator_tag, random_access_iterator_tag )
1358{
1359    if ( _VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
1360        return false;
1361    return _VSTD::equal<_RandomAccessIterator1, _RandomAccessIterator2,
1362                        typename add_lvalue_reference<_BinaryPredicate>::type>
1363                       (__first1, __last1, __first2, __pred );
1364}
1365
1366template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1367inline _LIBCPP_INLINE_VISIBILITY
1368bool
1369equal(_InputIterator1 __first1, _InputIterator1 __last1,
1370      _InputIterator2 __first2, _InputIterator2 __last2, _BinaryPredicate __pred )
1371{
1372    return _VSTD::__equal<typename add_lvalue_reference<_BinaryPredicate>::type>
1373       (__first1, __last1, __first2, __last2, __pred,
1374        typename iterator_traits<_InputIterator1>::iterator_category(),
1375        typename iterator_traits<_InputIterator2>::iterator_category());
1376}
1377
1378template <class _InputIterator1, class _InputIterator2>
1379inline _LIBCPP_INLINE_VISIBILITY
1380bool
1381equal(_InputIterator1 __first1, _InputIterator1 __last1,
1382      _InputIterator2 __first2, _InputIterator2 __last2)
1383{
1384    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1385    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1386    return _VSTD::__equal(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>(),
1387        typename iterator_traits<_InputIterator1>::iterator_category(),
1388        typename iterator_traits<_InputIterator2>::iterator_category());
1389}
1390#endif
1391
1392// is_permutation
1393
1394template<class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1395bool
1396is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1397               _ForwardIterator2 __first2, _BinaryPredicate __pred)
1398{
1399    // shorten sequences as much as possible by lopping of any equal parts
1400    for (; __first1 != __last1; ++__first1, (void) ++__first2)
1401        if (!__pred(*__first1, *__first2))
1402            goto __not_done;
1403    return true;
1404__not_done:
1405    // __first1 != __last1 && *__first1 != *__first2
1406    typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
1407    _D1 __l1 = _VSTD::distance(__first1, __last1);
1408    if (__l1 == _D1(1))
1409        return false;
1410    _ForwardIterator2 __last2 = _VSTD::next(__first2, __l1);
1411    // For each element in [f1, l1) see if there are the same number of
1412    //    equal elements in [f2, l2)
1413    for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i)
1414    {
1415        // Have we already counted the number of *__i in [f1, l1)?
1416        for (_ForwardIterator1 __j = __first1; __j != __i; ++__j)
1417            if (__pred(*__j, *__i))
1418                goto __next_iter;
1419        {
1420            // Count number of *__i in [f2, l2)
1421            _D1 __c2 = 0;
1422            for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
1423                if (__pred(*__i, *__j))
1424                    ++__c2;
1425            if (__c2 == 0)
1426                return false;
1427            // Count number of *__i in [__i, l1) (we can start with 1)
1428            _D1 __c1 = 1;
1429            for (_ForwardIterator1 __j = _VSTD::next(__i); __j != __last1; ++__j)
1430                if (__pred(*__i, *__j))
1431                    ++__c1;
1432            if (__c1 != __c2)
1433                return false;
1434        }
1435__next_iter:;
1436    }
1437    return true;
1438}
1439
1440template<class _ForwardIterator1, class _ForwardIterator2>
1441inline _LIBCPP_INLINE_VISIBILITY
1442bool
1443is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1444               _ForwardIterator2 __first2)
1445{
1446    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1447    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1448    return _VSTD::is_permutation(__first1, __last1, __first2, __equal_to<__v1, __v2>());
1449}
1450
1451#if _LIBCPP_STD_VER > 11
1452template<class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
1453bool
1454__is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1455                 _ForwardIterator2 __first2, _ForwardIterator2 __last2,
1456                 _BinaryPredicate __pred,
1457                 forward_iterator_tag, forward_iterator_tag )
1458{
1459    // shorten sequences as much as possible by lopping of any equal parts
1460    for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void) ++__first2)
1461        if (!__pred(*__first1, *__first2))
1462            goto __not_done;
1463    return __first1 == __last1 && __first2 == __last2;
1464__not_done:
1465    // __first1 != __last1 && __first2 != __last2 && *__first1 != *__first2
1466    typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
1467    _D1 __l1 = _VSTD::distance(__first1, __last1);
1468
1469    typedef typename iterator_traits<_ForwardIterator2>::difference_type _D2;
1470    _D2 __l2 = _VSTD::distance(__first2, __last2);
1471    if (__l1 != __l2)
1472        return false;
1473
1474    // For each element in [f1, l1) see if there are the same number of
1475    //    equal elements in [f2, l2)
1476    for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i)
1477    {
1478        // Have we already counted the number of *__i in [f1, l1)?
1479        for (_ForwardIterator1 __j = __first1; __j != __i; ++__j)
1480            if (__pred(*__j, *__i))
1481                goto __next_iter;
1482        {
1483            // Count number of *__i in [f2, l2)
1484            _D1 __c2 = 0;
1485            for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
1486                if (__pred(*__i, *__j))
1487                    ++__c2;
1488            if (__c2 == 0)
1489                return false;
1490            // Count number of *__i in [__i, l1) (we can start with 1)
1491            _D1 __c1 = 1;
1492            for (_ForwardIterator1 __j = _VSTD::next(__i); __j != __last1; ++__j)
1493                if (__pred(*__i, *__j))
1494                    ++__c1;
1495            if (__c1 != __c2)
1496                return false;
1497        }
1498__next_iter:;
1499    }
1500    return true;
1501}
1502
1503template<class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1504bool
1505__is_permutation(_RandomAccessIterator1 __first1, _RandomAccessIterator2 __last1,
1506               _RandomAccessIterator1 __first2, _RandomAccessIterator2 __last2,
1507               _BinaryPredicate __pred,
1508               random_access_iterator_tag, random_access_iterator_tag )
1509{
1510    if ( _VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
1511        return false;
1512    return _VSTD::is_permutation<_RandomAccessIterator1, _RandomAccessIterator2,
1513                                 typename add_lvalue_reference<_BinaryPredicate>::type>
1514                                (__first1, __last1, __first2, __pred );
1515}
1516
1517template<class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1518inline _LIBCPP_INLINE_VISIBILITY
1519bool
1520is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1521               _ForwardIterator2 __first2, _ForwardIterator2 __last2,
1522               _BinaryPredicate __pred )
1523{
1524    return _VSTD::__is_permutation<typename add_lvalue_reference<_BinaryPredicate>::type>
1525       (__first1, __last1, __first2, __last2, __pred,
1526        typename iterator_traits<_ForwardIterator1>::iterator_category(),
1527        typename iterator_traits<_ForwardIterator2>::iterator_category());
1528}
1529
1530template<class _ForwardIterator1, class _ForwardIterator2>
1531inline _LIBCPP_INLINE_VISIBILITY
1532bool
1533is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1534               _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1535{
1536    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1537    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1538    return _VSTD::__is_permutation(__first1, __last1, __first2, __last2,
1539        __equal_to<__v1, __v2>(),
1540        typename iterator_traits<_ForwardIterator1>::iterator_category(),
1541        typename iterator_traits<_ForwardIterator2>::iterator_category());
1542}
1543#endif
1544
1545// search
1546
1547template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
1548pair<_ForwardIterator1, _ForwardIterator1>
1549__search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1550         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
1551         forward_iterator_tag, forward_iterator_tag)
1552{
1553    if (__first2 == __last2)
1554        return make_pair(__first1, __first1);  // Everything matches an empty sequence
1555    while (true)
1556    {
1557        // Find first element in sequence 1 that matchs *__first2, with a mininum of loop checks
1558        while (true)
1559        {
1560            if (__first1 == __last1)  // return __last1 if no element matches *__first2
1561                return make_pair(__last1, __last1);
1562            if (__pred(*__first1, *__first2))
1563                break;
1564            ++__first1;
1565        }
1566        // *__first1 matches *__first2, now match elements after here
1567        _ForwardIterator1 __m1 = __first1;
1568        _ForwardIterator2 __m2 = __first2;
1569        while (true)
1570        {
1571            if (++__m2 == __last2)  // If pattern exhausted, __first1 is the answer (works for 1 element pattern)
1572                return make_pair(__first1, __m1);
1573            if (++__m1 == __last1)  // Otherwise if source exhaused, pattern not found
1574                return make_pair(__last1, __last1);
1575            if (!__pred(*__m1, *__m2))  // if there is a mismatch, restart with a new __first1
1576            {
1577                ++__first1;
1578                break;
1579            }  // else there is a match, check next elements
1580        }
1581    }
1582}
1583
1584template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1585_LIBCPP_CONSTEXPR_AFTER_CXX11
1586pair<_RandomAccessIterator1, _RandomAccessIterator1>
1587__search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
1588         _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
1589           random_access_iterator_tag, random_access_iterator_tag)
1590{
1591    typedef typename iterator_traits<_RandomAccessIterator1>::difference_type _D1;
1592    typedef typename iterator_traits<_RandomAccessIterator2>::difference_type _D2;
1593    // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
1594    const _D2 __len2 = __last2 - __first2;
1595    if (__len2 == 0)
1596        return make_pair(__first1, __first1);
1597    const _D1 __len1 = __last1 - __first1;
1598    if (__len1 < __len2)
1599        return make_pair(__last1, __last1);
1600    const _RandomAccessIterator1 __s = __last1 - (__len2 - 1);  // Start of pattern match can't go beyond here
1601
1602    while (true)
1603    {
1604        while (true)
1605        {
1606            if (__first1 == __s)
1607                return make_pair(__last1, __last1);
1608            if (__pred(*__first1, *__first2))
1609                break;
1610            ++__first1;
1611        }
1612
1613        _RandomAccessIterator1 __m1 = __first1;
1614        _RandomAccessIterator2 __m2 = __first2;
1615         while (true)
1616         {
1617             if (++__m2 == __last2)
1618                 return make_pair(__first1, __first1 + __len2);
1619             ++__m1;          // no need to check range on __m1 because __s guarantees we have enough source
1620             if (!__pred(*__m1, *__m2))
1621             {
1622                 ++__first1;
1623                 break;
1624             }
1625         }
1626    }
1627}
1628
1629template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1630inline _LIBCPP_INLINE_VISIBILITY
1631_ForwardIterator1
1632search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1633       _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1634{
1635    return _VSTD::__search<typename add_lvalue_reference<_BinaryPredicate>::type>
1636                         (__first1, __last1, __first2, __last2, __pred,
1637                          typename iterator_traits<_ForwardIterator1>::iterator_category(),
1638                          typename iterator_traits<_ForwardIterator2>::iterator_category())
1639            .first;
1640}
1641
1642template <class _ForwardIterator1, class _ForwardIterator2>
1643inline _LIBCPP_INLINE_VISIBILITY
1644_ForwardIterator1
1645search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1646       _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1647{
1648    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1649    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1650    return _VSTD::search(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1651}
1652
1653// search_n
1654
1655template <class _BinaryPredicate, class _ForwardIterator, class _Size, class _Tp>
1656_ForwardIterator
1657__search_n(_ForwardIterator __first, _ForwardIterator __last,
1658           _Size __count, const _Tp& __value_, _BinaryPredicate __pred, forward_iterator_tag)
1659{
1660    if (__count <= 0)
1661        return __first;
1662    while (true)
1663    {
1664        // Find first element in sequence that matchs __value_, with a mininum of loop checks
1665        while (true)
1666        {
1667            if (__first == __last)  // return __last if no element matches __value_
1668                return __last;
1669            if (__pred(*__first, __value_))
1670                break;
1671            ++__first;
1672        }
1673        // *__first matches __value_, now match elements after here
1674        _ForwardIterator __m = __first;
1675        _Size __c(0);
1676        while (true)
1677        {
1678            if (++__c == __count)  // If pattern exhausted, __first is the answer (works for 1 element pattern)
1679                return __first;
1680            if (++__m == __last)  // Otherwise if source exhaused, pattern not found
1681                return __last;
1682            if (!__pred(*__m, __value_))  // if there is a mismatch, restart with a new __first
1683            {
1684                __first = __m;
1685                ++__first;
1686                break;
1687            }  // else there is a match, check next elements
1688        }
1689    }
1690}
1691
1692template <class _BinaryPredicate, class _RandomAccessIterator, class _Size, class _Tp>
1693_RandomAccessIterator
1694__search_n(_RandomAccessIterator __first, _RandomAccessIterator __last,
1695           _Size __count, const _Tp& __value_, _BinaryPredicate __pred, random_access_iterator_tag)
1696{
1697    if (__count <= 0)
1698        return __first;
1699    _Size __len = static_cast<_Size>(__last - __first);
1700    if (__len < __count)
1701        return __last;
1702    const _RandomAccessIterator __s = __last - (__count - 1);  // Start of pattern match can't go beyond here
1703    while (true)
1704    {
1705        // Find first element in sequence that matchs __value_, with a mininum of loop checks
1706        while (true)
1707        {
1708            if (__first >= __s)  // return __last if no element matches __value_
1709                return __last;
1710            if (__pred(*__first, __value_))
1711                break;
1712            ++__first;
1713        }
1714        // *__first matches __value_, now match elements after here
1715        _RandomAccessIterator __m = __first;
1716        _Size __c(0);
1717        while (true)
1718        {
1719            if (++__c == __count)  // If pattern exhausted, __first is the answer (works for 1 element pattern)
1720                return __first;
1721             ++__m;          // no need to check range on __m because __s guarantees we have enough source
1722            if (!__pred(*__m, __value_))  // if there is a mismatch, restart with a new __first
1723            {
1724                __first = __m;
1725                ++__first;
1726                break;
1727            }  // else there is a match, check next elements
1728        }
1729    }
1730}
1731
1732template <class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
1733inline _LIBCPP_INLINE_VISIBILITY
1734_ForwardIterator
1735search_n(_ForwardIterator __first, _ForwardIterator __last,
1736         _Size __count, const _Tp& __value_, _BinaryPredicate __pred)
1737{
1738    return _VSTD::__search_n<typename add_lvalue_reference<_BinaryPredicate>::type>
1739           (__first, __last, __convert_to_integral(__count), __value_, __pred,
1740           typename iterator_traits<_ForwardIterator>::iterator_category());
1741}
1742
1743template <class _ForwardIterator, class _Size, class _Tp>
1744inline _LIBCPP_INLINE_VISIBILITY
1745_ForwardIterator
1746search_n(_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value_)
1747{
1748    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
1749    return _VSTD::search_n(__first, __last, __convert_to_integral(__count),
1750                           __value_, __equal_to<__v, _Tp>());
1751}
1752
1753// copy
1754template <class _Iter>
1755inline _LIBCPP_INLINE_VISIBILITY
1756_Iter
1757__unwrap_iter(_Iter __i)
1758{
1759    return __i;
1760}
1761
1762template <class _Tp>
1763inline _LIBCPP_INLINE_VISIBILITY
1764typename enable_if
1765<
1766    is_trivially_copy_assignable<_Tp>::value,
1767    _Tp*
1768>::type
1769__unwrap_iter(move_iterator<_Tp*> __i)
1770{
1771    return __i.base();
1772}
1773
1774#if _LIBCPP_DEBUG_LEVEL < 2
1775
1776template <class _Tp>
1777inline _LIBCPP_INLINE_VISIBILITY
1778typename enable_if
1779<
1780    is_trivially_copy_assignable<_Tp>::value,
1781    _Tp*
1782>::type
1783__unwrap_iter(__wrap_iter<_Tp*> __i)
1784{
1785    return __i.base();
1786}
1787
1788#else
1789
1790template <class _Tp>
1791inline _LIBCPP_INLINE_VISIBILITY
1792typename enable_if
1793<
1794    is_trivially_copy_assignable<_Tp>::value,
1795    __wrap_iter<_Tp*>
1796>::type
1797__unwrap_iter(__wrap_iter<_Tp*> __i)
1798{
1799    return __i;
1800}
1801
1802#endif  // _LIBCPP_DEBUG_LEVEL < 2
1803
1804template <class _InputIterator, class _OutputIterator>
1805inline _LIBCPP_INLINE_VISIBILITY
1806_OutputIterator
1807__copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1808{
1809    for (; __first != __last; ++__first, (void) ++__result)
1810        *__result = *__first;
1811    return __result;
1812}
1813
1814template <class _Tp, class _Up>
1815inline _LIBCPP_INLINE_VISIBILITY
1816typename enable_if
1817<
1818    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1819    is_trivially_copy_assignable<_Up>::value,
1820    _Up*
1821>::type
1822__copy(_Tp* __first, _Tp* __last, _Up* __result)
1823{
1824    const size_t __n = static_cast<size_t>(__last - __first);
1825    if (__n > 0)
1826        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1827    return __result + __n;
1828}
1829
1830template <class _InputIterator, class _OutputIterator>
1831inline _LIBCPP_INLINE_VISIBILITY
1832_OutputIterator
1833copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1834{
1835    return _VSTD::__copy(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
1836}
1837
1838// copy_backward
1839
1840template <class _BidirectionalIterator, class _OutputIterator>
1841inline _LIBCPP_INLINE_VISIBILITY
1842_OutputIterator
1843__copy_backward(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
1844{
1845    while (__first != __last)
1846        *--__result = *--__last;
1847    return __result;
1848}
1849
1850template <class _Tp, class _Up>
1851inline _LIBCPP_INLINE_VISIBILITY
1852typename enable_if
1853<
1854    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1855    is_trivially_copy_assignable<_Up>::value,
1856    _Up*
1857>::type
1858__copy_backward(_Tp* __first, _Tp* __last, _Up* __result)
1859{
1860    const size_t __n = static_cast<size_t>(__last - __first);
1861    if (__n > 0)
1862    {
1863        __result -= __n;
1864        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1865    }
1866    return __result;
1867}
1868
1869template <class _BidirectionalIterator1, class _BidirectionalIterator2>
1870inline _LIBCPP_INLINE_VISIBILITY
1871_BidirectionalIterator2
1872copy_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
1873              _BidirectionalIterator2 __result)
1874{
1875    return _VSTD::__copy_backward(__unwrap_iter(__first),
1876                                  __unwrap_iter(__last),
1877                                  __unwrap_iter(__result));
1878}
1879
1880// copy_if
1881
1882template<class _InputIterator, class _OutputIterator, class _Predicate>
1883inline _LIBCPP_INLINE_VISIBILITY
1884_OutputIterator
1885copy_if(_InputIterator __first, _InputIterator __last,
1886        _OutputIterator __result, _Predicate __pred)
1887{
1888    for (; __first != __last; ++__first)
1889    {
1890        if (__pred(*__first))
1891        {
1892            *__result = *__first;
1893            ++__result;
1894        }
1895    }
1896    return __result;
1897}
1898
1899// copy_n
1900
1901template<class _InputIterator, class _Size, class _OutputIterator>
1902inline _LIBCPP_INLINE_VISIBILITY
1903typename enable_if
1904<
1905    __is_input_iterator<_InputIterator>::value &&
1906   !__is_random_access_iterator<_InputIterator>::value,
1907    _OutputIterator
1908>::type
1909copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
1910{
1911    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
1912    _IntegralSize __n = __orig_n;
1913    if (__n > 0)
1914    {
1915        *__result = *__first;
1916        ++__result;
1917        for (--__n; __n > 0; --__n)
1918        {
1919            ++__first;
1920            *__result = *__first;
1921            ++__result;
1922        }
1923    }
1924    return __result;
1925}
1926
1927template<class _InputIterator, class _Size, class _OutputIterator>
1928inline _LIBCPP_INLINE_VISIBILITY
1929typename enable_if
1930<
1931    __is_random_access_iterator<_InputIterator>::value,
1932    _OutputIterator
1933>::type
1934copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
1935{
1936    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
1937    _IntegralSize __n = __orig_n;
1938    return _VSTD::copy(__first, __first + __n, __result);
1939}
1940
1941// move
1942
1943template <class _InputIterator, class _OutputIterator>
1944inline _LIBCPP_INLINE_VISIBILITY
1945_OutputIterator
1946__move(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1947{
1948    for (; __first != __last; ++__first, (void) ++__result)
1949        *__result = _VSTD::move(*__first);
1950    return __result;
1951}
1952
1953template <class _Tp, class _Up>
1954inline _LIBCPP_INLINE_VISIBILITY
1955typename enable_if
1956<
1957    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1958    is_trivially_copy_assignable<_Up>::value,
1959    _Up*
1960>::type
1961__move(_Tp* __first, _Tp* __last, _Up* __result)
1962{
1963    const size_t __n = static_cast<size_t>(__last - __first);
1964    if (__n > 0)
1965        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1966    return __result + __n;
1967}
1968
1969template <class _InputIterator, class _OutputIterator>
1970inline _LIBCPP_INLINE_VISIBILITY
1971_OutputIterator
1972move(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1973{
1974    return _VSTD::__move(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
1975}
1976
1977// move_backward
1978
1979template <class _InputIterator, class _OutputIterator>
1980inline _LIBCPP_INLINE_VISIBILITY
1981_OutputIterator
1982__move_backward(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1983{
1984    while (__first != __last)
1985        *--__result = _VSTD::move(*--__last);
1986    return __result;
1987}
1988
1989template <class _Tp, class _Up>
1990inline _LIBCPP_INLINE_VISIBILITY
1991typename enable_if
1992<
1993    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1994    is_trivially_copy_assignable<_Up>::value,
1995    _Up*
1996>::type
1997__move_backward(_Tp* __first, _Tp* __last, _Up* __result)
1998{
1999    const size_t __n = static_cast<size_t>(__last - __first);
2000    if (__n > 0)
2001    {
2002        __result -= __n;
2003        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
2004    }
2005    return __result;
2006}
2007
2008template <class _BidirectionalIterator1, class _BidirectionalIterator2>
2009inline _LIBCPP_INLINE_VISIBILITY
2010_BidirectionalIterator2
2011move_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
2012              _BidirectionalIterator2 __result)
2013{
2014    return _VSTD::__move_backward(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
2015}
2016
2017// iter_swap
2018
2019// moved to <type_traits> for better swap / noexcept support
2020
2021// transform
2022
2023template <class _InputIterator, class _OutputIterator, class _UnaryOperation>
2024inline _LIBCPP_INLINE_VISIBILITY
2025_OutputIterator
2026transform(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _UnaryOperation __op)
2027{
2028    for (; __first != __last; ++__first, (void) ++__result)
2029        *__result = __op(*__first);
2030    return __result;
2031}
2032
2033template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _BinaryOperation>
2034inline _LIBCPP_INLINE_VISIBILITY
2035_OutputIterator
2036transform(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2,
2037          _OutputIterator __result, _BinaryOperation __binary_op)
2038{
2039    for (; __first1 != __last1; ++__first1, (void) ++__first2, ++__result)
2040        *__result = __binary_op(*__first1, *__first2);
2041    return __result;
2042}
2043
2044// replace
2045
2046template <class _ForwardIterator, class _Tp>
2047inline _LIBCPP_INLINE_VISIBILITY
2048void
2049replace(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __old_value, const _Tp& __new_value)
2050{
2051    for (; __first != __last; ++__first)
2052        if (*__first == __old_value)
2053            *__first = __new_value;
2054}
2055
2056// replace_if
2057
2058template <class _ForwardIterator, class _Predicate, class _Tp>
2059inline _LIBCPP_INLINE_VISIBILITY
2060void
2061replace_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, const _Tp& __new_value)
2062{
2063    for (; __first != __last; ++__first)
2064        if (__pred(*__first))
2065            *__first = __new_value;
2066}
2067
2068// replace_copy
2069
2070template <class _InputIterator, class _OutputIterator, class _Tp>
2071inline _LIBCPP_INLINE_VISIBILITY
2072_OutputIterator
2073replace_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
2074             const _Tp& __old_value, const _Tp& __new_value)
2075{
2076    for (; __first != __last; ++__first, (void) ++__result)
2077        if (*__first == __old_value)
2078            *__result = __new_value;
2079        else
2080            *__result = *__first;
2081    return __result;
2082}
2083
2084// replace_copy_if
2085
2086template <class _InputIterator, class _OutputIterator, class _Predicate, class _Tp>
2087inline _LIBCPP_INLINE_VISIBILITY
2088_OutputIterator
2089replace_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
2090                _Predicate __pred, const _Tp& __new_value)
2091{
2092    for (; __first != __last; ++__first, (void) ++__result)
2093        if (__pred(*__first))
2094            *__result = __new_value;
2095        else
2096            *__result = *__first;
2097    return __result;
2098}
2099
2100// fill_n
2101
2102template <class _OutputIterator, class _Size, class _Tp>
2103inline _LIBCPP_INLINE_VISIBILITY
2104_OutputIterator
2105__fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
2106{
2107    for (; __n > 0; ++__first, (void) --__n)
2108        *__first = __value_;
2109    return __first;
2110}
2111
2112template <class _Tp, class _Size, class _Up>
2113inline _LIBCPP_INLINE_VISIBILITY
2114typename enable_if
2115<
2116    is_integral<_Tp>::value && sizeof(_Tp) == 1 &&
2117    !is_same<_Tp, bool>::value &&
2118    is_integral<_Up>::value && sizeof(_Up) == 1,
2119    _Tp*
2120>::type
2121__fill_n(_Tp* __first, _Size __n,_Up __value_)
2122{
2123    if (__n > 0)
2124        _VSTD::memset(__first, (unsigned char)__value_, (size_t)(__n));
2125    return __first + __n;
2126}
2127
2128template <class _OutputIterator, class _Size, class _Tp>
2129inline _LIBCPP_INLINE_VISIBILITY
2130_OutputIterator
2131fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
2132{
2133   return _VSTD::__fill_n(__first, __convert_to_integral(__n), __value_);
2134}
2135
2136// fill
2137
2138template <class _ForwardIterator, class _Tp>
2139inline _LIBCPP_INLINE_VISIBILITY
2140void
2141__fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, forward_iterator_tag)
2142{
2143    for (; __first != __last; ++__first)
2144        *__first = __value_;
2145}
2146
2147template <class _RandomAccessIterator, class _Tp>
2148inline _LIBCPP_INLINE_VISIBILITY
2149void
2150__fill(_RandomAccessIterator __first, _RandomAccessIterator __last, const _Tp& __value_, random_access_iterator_tag)
2151{
2152    _VSTD::fill_n(__first, __last - __first, __value_);
2153}
2154
2155template <class _ForwardIterator, class _Tp>
2156inline _LIBCPP_INLINE_VISIBILITY
2157void
2158fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
2159{
2160    _VSTD::__fill(__first, __last, __value_, typename iterator_traits<_ForwardIterator>::iterator_category());
2161}
2162
2163// generate
2164
2165template <class _ForwardIterator, class _Generator>
2166inline _LIBCPP_INLINE_VISIBILITY
2167void
2168generate(_ForwardIterator __first, _ForwardIterator __last, _Generator __gen)
2169{
2170    for (; __first != __last; ++__first)
2171        *__first = __gen();
2172}
2173
2174// generate_n
2175
2176template <class _OutputIterator, class _Size, class _Generator>
2177inline _LIBCPP_INLINE_VISIBILITY
2178_OutputIterator
2179generate_n(_OutputIterator __first, _Size __orig_n, _Generator __gen)
2180{
2181    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
2182    _IntegralSize __n = __orig_n;
2183    for (; __n > 0; ++__first, (void) --__n)
2184        *__first = __gen();
2185    return __first;
2186}
2187
2188// remove
2189
2190template <class _ForwardIterator, class _Tp>
2191_ForwardIterator
2192remove(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
2193{
2194    __first = _VSTD::find(__first, __last, __value_);
2195    if (__first != __last)
2196    {
2197        _ForwardIterator __i = __first;
2198        while (++__i != __last)
2199        {
2200            if (!(*__i == __value_))
2201            {
2202                *__first = _VSTD::move(*__i);
2203                ++__first;
2204            }
2205        }
2206    }
2207    return __first;
2208}
2209
2210// remove_if
2211
2212template <class _ForwardIterator, class _Predicate>
2213_ForwardIterator
2214remove_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
2215{
2216    __first = _VSTD::find_if<_ForwardIterator, typename add_lvalue_reference<_Predicate>::type>
2217                           (__first, __last, __pred);
2218    if (__first != __last)
2219    {
2220        _ForwardIterator __i = __first;
2221        while (++__i != __last)
2222        {
2223            if (!__pred(*__i))
2224            {
2225                *__first = _VSTD::move(*__i);
2226                ++__first;
2227            }
2228        }
2229    }
2230    return __first;
2231}
2232
2233// remove_copy
2234
2235template <class _InputIterator, class _OutputIterator, class _Tp>
2236inline _LIBCPP_INLINE_VISIBILITY
2237_OutputIterator
2238remove_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, const _Tp& __value_)
2239{
2240    for (; __first != __last; ++__first)
2241    {
2242        if (!(*__first == __value_))
2243        {
2244            *__result = *__first;
2245            ++__result;
2246        }
2247    }
2248    return __result;
2249}
2250
2251// remove_copy_if
2252
2253template <class _InputIterator, class _OutputIterator, class _Predicate>
2254inline _LIBCPP_INLINE_VISIBILITY
2255_OutputIterator
2256remove_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Predicate __pred)
2257{
2258    for (; __first != __last; ++__first)
2259    {
2260        if (!__pred(*__first))
2261        {
2262            *__result = *__first;
2263            ++__result;
2264        }
2265    }
2266    return __result;
2267}
2268
2269// unique
2270
2271template <class _ForwardIterator, class _BinaryPredicate>
2272_ForwardIterator
2273unique(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
2274{
2275    __first = _VSTD::adjacent_find<_ForwardIterator, typename add_lvalue_reference<_BinaryPredicate>::type>
2276                                 (__first, __last, __pred);
2277    if (__first != __last)
2278    {
2279        // ...  a  a  ?  ...
2280        //      f     i
2281        _ForwardIterator __i = __first;
2282        for (++__i; ++__i != __last;)
2283            if (!__pred(*__first, *__i))
2284                *++__first = _VSTD::move(*__i);
2285        ++__first;
2286    }
2287    return __first;
2288}
2289
2290template <class _ForwardIterator>
2291inline _LIBCPP_INLINE_VISIBILITY
2292_ForwardIterator
2293unique(_ForwardIterator __first, _ForwardIterator __last)
2294{
2295    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
2296    return _VSTD::unique(__first, __last, __equal_to<__v>());
2297}
2298
2299// unique_copy
2300
2301template <class _BinaryPredicate, class _InputIterator, class _OutputIterator>
2302_OutputIterator
2303__unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred,
2304              input_iterator_tag, output_iterator_tag)
2305{
2306    if (__first != __last)
2307    {
2308        typename iterator_traits<_InputIterator>::value_type __t(*__first);
2309        *__result = __t;
2310        ++__result;
2311        while (++__first != __last)
2312        {
2313            if (!__pred(__t, *__first))
2314            {
2315                __t = *__first;
2316                *__result = __t;
2317                ++__result;
2318            }
2319        }
2320    }
2321    return __result;
2322}
2323
2324template <class _BinaryPredicate, class _ForwardIterator, class _OutputIterator>
2325_OutputIterator
2326__unique_copy(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result, _BinaryPredicate __pred,
2327              forward_iterator_tag, output_iterator_tag)
2328{
2329    if (__first != __last)
2330    {
2331        _ForwardIterator __i = __first;
2332        *__result = *__i;
2333        ++__result;
2334        while (++__first != __last)
2335        {
2336            if (!__pred(*__i, *__first))
2337            {
2338                *__result = *__first;
2339                ++__result;
2340                __i = __first;
2341            }
2342        }
2343    }
2344    return __result;
2345}
2346
2347template <class _BinaryPredicate, class _InputIterator, class _ForwardIterator>
2348_ForwardIterator
2349__unique_copy(_InputIterator __first, _InputIterator __last, _ForwardIterator __result, _BinaryPredicate __pred,
2350              input_iterator_tag, forward_iterator_tag)
2351{
2352    if (__first != __last)
2353    {
2354        *__result = *__first;
2355        while (++__first != __last)
2356            if (!__pred(*__result, *__first))
2357                *++__result = *__first;
2358        ++__result;
2359    }
2360    return __result;
2361}
2362
2363template <class _InputIterator, class _OutputIterator, class _BinaryPredicate>
2364inline _LIBCPP_INLINE_VISIBILITY
2365_OutputIterator
2366unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred)
2367{
2368    return _VSTD::__unique_copy<typename add_lvalue_reference<_BinaryPredicate>::type>
2369                              (__first, __last, __result, __pred,
2370                               typename iterator_traits<_InputIterator>::iterator_category(),
2371                               typename iterator_traits<_OutputIterator>::iterator_category());
2372}
2373
2374template <class _InputIterator, class _OutputIterator>
2375inline _LIBCPP_INLINE_VISIBILITY
2376_OutputIterator
2377unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
2378{
2379    typedef typename iterator_traits<_InputIterator>::value_type __v;
2380    return _VSTD::unique_copy(__first, __last, __result, __equal_to<__v>());
2381}
2382
2383// reverse
2384
2385template <class _BidirectionalIterator>
2386inline _LIBCPP_INLINE_VISIBILITY
2387void
2388__reverse(_BidirectionalIterator __first, _BidirectionalIterator __last, bidirectional_iterator_tag)
2389{
2390    while (__first != __last)
2391    {
2392        if (__first == --__last)
2393            break;
2394        _VSTD::iter_swap(__first, __last);
2395        ++__first;
2396    }
2397}
2398
2399template <class _RandomAccessIterator>
2400inline _LIBCPP_INLINE_VISIBILITY
2401void
2402__reverse(_RandomAccessIterator __first, _RandomAccessIterator __last, random_access_iterator_tag)
2403{
2404    if (__first != __last)
2405        for (; __first < --__last; ++__first)
2406            _VSTD::iter_swap(__first, __last);
2407}
2408
2409template <class _BidirectionalIterator>
2410inline _LIBCPP_INLINE_VISIBILITY
2411void
2412reverse(_BidirectionalIterator __first, _BidirectionalIterator __last)
2413{
2414    _VSTD::__reverse(__first, __last, typename iterator_traits<_BidirectionalIterator>::iterator_category());
2415}
2416
2417// reverse_copy
2418
2419template <class _BidirectionalIterator, class _OutputIterator>
2420inline _LIBCPP_INLINE_VISIBILITY
2421_OutputIterator
2422reverse_copy(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
2423{
2424    for (; __first != __last; ++__result)
2425        *__result = *--__last;
2426    return __result;
2427}
2428
2429// rotate
2430
2431template <class _ForwardIterator>
2432_ForwardIterator
2433__rotate_left(_ForwardIterator __first, _ForwardIterator __last)
2434{
2435    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
2436    value_type __tmp = _VSTD::move(*__first);
2437    _ForwardIterator __lm1 = _VSTD::move(_VSTD::next(__first), __last, __first);
2438    *__lm1 = _VSTD::move(__tmp);
2439    return __lm1;
2440}
2441
2442template <class _BidirectionalIterator>
2443_BidirectionalIterator
2444__rotate_right(_BidirectionalIterator __first, _BidirectionalIterator __last)
2445{
2446    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
2447    _BidirectionalIterator __lm1 = _VSTD::prev(__last);
2448    value_type __tmp = _VSTD::move(*__lm1);
2449    _BidirectionalIterator __fp1 = _VSTD::move_backward(__first, __lm1, __last);
2450    *__first = _VSTD::move(__tmp);
2451    return __fp1;
2452}
2453
2454template <class _ForwardIterator>
2455_ForwardIterator
2456__rotate_forward(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
2457{
2458    _ForwardIterator __i = __middle;
2459    while (true)
2460    {
2461        swap(*__first, *__i);
2462        ++__first;
2463        if (++__i == __last)
2464            break;
2465        if (__first == __middle)
2466            __middle = __i;
2467    }
2468    _ForwardIterator __r = __first;
2469    if (__first != __middle)
2470    {
2471        __i = __middle;
2472        while (true)
2473        {
2474            swap(*__first, *__i);
2475            ++__first;
2476            if (++__i == __last)
2477            {
2478                if (__first == __middle)
2479                    break;
2480                __i = __middle;
2481            }
2482            else if (__first == __middle)
2483                __middle = __i;
2484        }
2485    }
2486    return __r;
2487}
2488
2489template<typename _Integral>
2490inline _LIBCPP_INLINE_VISIBILITY
2491_Integral
2492__algo_gcd(_Integral __x, _Integral __y)
2493{
2494    do
2495    {
2496        _Integral __t = __x % __y;
2497        __x = __y;
2498        __y = __t;
2499    } while (__y);
2500    return __x;
2501}
2502
2503template<typename _RandomAccessIterator>
2504_RandomAccessIterator
2505__rotate_gcd(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)
2506{
2507    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
2508    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
2509
2510    const difference_type __m1 = __middle - __first;
2511    const difference_type __m2 = __last - __middle;
2512    if (__m1 == __m2)
2513    {
2514        _VSTD::swap_ranges(__first, __middle, __middle);
2515        return __middle;
2516    }
2517    const difference_type __g = _VSTD::__algo_gcd(__m1, __m2);
2518    for (_RandomAccessIterator __p = __first + __g; __p != __first;)
2519    {
2520        value_type __t(_VSTD::move(*--__p));
2521        _RandomAccessIterator __p1 = __p;
2522        _RandomAccessIterator __p2 = __p1 + __m1;
2523        do
2524        {
2525            *__p1 = _VSTD::move(*__p2);
2526            __p1 = __p2;
2527            const difference_type __d = __last - __p2;
2528            if (__m1 < __d)
2529                __p2 += __m1;
2530            else
2531                __p2 = __first + (__m1 - __d);
2532        } while (__p2 != __p);
2533        *__p1 = _VSTD::move(__t);
2534    }
2535    return __first + __m2;
2536}
2537
2538template <class _ForwardIterator>
2539inline _LIBCPP_INLINE_VISIBILITY
2540_ForwardIterator
2541__rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last,
2542         _VSTD::forward_iterator_tag)
2543{
2544    typedef typename _VSTD::iterator_traits<_ForwardIterator>::value_type value_type;
2545    if (_VSTD::is_trivially_move_assignable<value_type>::value)
2546    {
2547        if (_VSTD::next(__first) == __middle)
2548            return _VSTD::__rotate_left(__first, __last);
2549    }
2550    return _VSTD::__rotate_forward(__first, __middle, __last);
2551}
2552
2553template <class _BidirectionalIterator>
2554inline _LIBCPP_INLINE_VISIBILITY
2555_BidirectionalIterator
2556__rotate(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
2557         _VSTD::bidirectional_iterator_tag)
2558{
2559    typedef typename _VSTD::iterator_traits<_BidirectionalIterator>::value_type value_type;
2560    if (_VSTD::is_trivially_move_assignable<value_type>::value)
2561    {
2562        if (_VSTD::next(__first) == __middle)
2563            return _VSTD::__rotate_left(__first, __last);
2564        if (_VSTD::next(__middle) == __last)
2565            return _VSTD::__rotate_right(__first, __last);
2566    }
2567    return _VSTD::__rotate_forward(__first, __middle, __last);
2568}
2569
2570template <class _RandomAccessIterator>
2571inline _LIBCPP_INLINE_VISIBILITY
2572_RandomAccessIterator
2573__rotate(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
2574         _VSTD::random_access_iterator_tag)
2575{
2576    typedef typename _VSTD::iterator_traits<_RandomAccessIterator>::value_type value_type;
2577    if (_VSTD::is_trivially_move_assignable<value_type>::value)
2578    {
2579        if (_VSTD::next(__first) == __middle)
2580            return _VSTD::__rotate_left(__first, __last);
2581        if (_VSTD::next(__middle) == __last)
2582            return _VSTD::__rotate_right(__first, __last);
2583        return _VSTD::__rotate_gcd(__first, __middle, __last);
2584    }
2585    return _VSTD::__rotate_forward(__first, __middle, __last);
2586}
2587
2588template <class _ForwardIterator>
2589inline _LIBCPP_INLINE_VISIBILITY
2590_ForwardIterator
2591rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
2592{
2593    if (__first == __middle)
2594        return __last;
2595    if (__middle == __last)
2596        return __first;
2597    return _VSTD::__rotate(__first, __middle, __last,
2598                           typename _VSTD::iterator_traits<_ForwardIterator>::iterator_category());
2599}
2600
2601// rotate_copy
2602
2603template <class _ForwardIterator, class _OutputIterator>
2604inline _LIBCPP_INLINE_VISIBILITY
2605_OutputIterator
2606rotate_copy(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last, _OutputIterator __result)
2607{
2608    return _VSTD::copy(__first, __middle, _VSTD::copy(__middle, __last, __result));
2609}
2610
2611// min_element
2612
2613template <class _ForwardIterator, class _Compare>
2614inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2615_ForwardIterator
2616min_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2617{
2618    if (__first != __last)
2619    {
2620        _ForwardIterator __i = __first;
2621        while (++__i != __last)
2622            if (__comp(*__i, *__first))
2623                __first = __i;
2624    }
2625    return __first;
2626}
2627
2628template <class _ForwardIterator>
2629inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2630_ForwardIterator
2631min_element(_ForwardIterator __first, _ForwardIterator __last)
2632{
2633    return _VSTD::min_element(__first, __last,
2634              __less<typename iterator_traits<_ForwardIterator>::value_type>());
2635}
2636
2637// min
2638
2639template <class _Tp, class _Compare>
2640inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2641const _Tp&
2642min(const _Tp& __a, const _Tp& __b, _Compare __comp)
2643{
2644    return __comp(__b, __a) ? __b : __a;
2645}
2646
2647template <class _Tp>
2648inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2649const _Tp&
2650min(const _Tp& __a, const _Tp& __b)
2651{
2652    return _VSTD::min(__a, __b, __less<_Tp>());
2653}
2654
2655#ifndef _LIBCPP_CXX03_LANG
2656
2657template<class _Tp, class _Compare>
2658inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2659_Tp
2660min(initializer_list<_Tp> __t, _Compare __comp)
2661{
2662    return *_VSTD::min_element(__t.begin(), __t.end(), __comp);
2663}
2664
2665template<class _Tp>
2666inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2667_Tp
2668min(initializer_list<_Tp> __t)
2669{
2670    return *_VSTD::min_element(__t.begin(), __t.end(), __less<_Tp>());
2671}
2672
2673#endif  // _LIBCPP_CXX03_LANG
2674
2675// max_element
2676
2677template <class _ForwardIterator, class _Compare>
2678inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2679_ForwardIterator
2680max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2681{
2682    if (__first != __last)
2683    {
2684        _ForwardIterator __i = __first;
2685        while (++__i != __last)
2686            if (__comp(*__first, *__i))
2687                __first = __i;
2688    }
2689    return __first;
2690}
2691
2692
2693template <class _ForwardIterator>
2694inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2695_ForwardIterator
2696max_element(_ForwardIterator __first, _ForwardIterator __last)
2697{
2698    return _VSTD::max_element(__first, __last,
2699              __less<typename iterator_traits<_ForwardIterator>::value_type>());
2700}
2701
2702// max
2703
2704template <class _Tp, class _Compare>
2705inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2706const _Tp&
2707max(const _Tp& __a, const _Tp& __b, _Compare __comp)
2708{
2709    return __comp(__a, __b) ? __b : __a;
2710}
2711
2712template <class _Tp>
2713inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2714const _Tp&
2715max(const _Tp& __a, const _Tp& __b)
2716{
2717    return _VSTD::max(__a, __b, __less<_Tp>());
2718}
2719
2720#ifndef _LIBCPP_CXX03_LANG
2721
2722template<class _Tp, class _Compare>
2723inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2724_Tp
2725max(initializer_list<_Tp> __t, _Compare __comp)
2726{
2727    return *_VSTD::max_element(__t.begin(), __t.end(), __comp);
2728}
2729
2730template<class _Tp>
2731inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2732_Tp
2733max(initializer_list<_Tp> __t)
2734{
2735    return *_VSTD::max_element(__t.begin(), __t.end(), __less<_Tp>());
2736}
2737
2738#endif  // _LIBCPP_CXX03_LANG
2739
2740#if _LIBCPP_STD_VER > 14
2741// clamp
2742template<class _Tp, class _Compare>
2743inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2744const _Tp&
2745clamp(const _Tp& __v, const _Tp& __lo, const _Tp& __hi, _Compare __comp)
2746{
2747    _LIBCPP_ASSERT(!__comp(__hi, __lo), "Bad bounds passed to std::clamp");
2748    return __comp(__v, __lo) ? __lo : __comp(__hi, __v) ? __hi : __v;
2749
2750}
2751
2752template<class _Tp>
2753inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
2754const _Tp&
2755clamp(const _Tp& __v, const _Tp& __lo, const _Tp& __hi)
2756{
2757    return _VSTD::clamp(__v, __lo, __hi, __less<_Tp>());
2758}
2759#endif
2760
2761// minmax_element
2762
2763template <class _ForwardIterator, class _Compare>
2764_LIBCPP_CONSTEXPR_AFTER_CXX11
2765std::pair<_ForwardIterator, _ForwardIterator>
2766minmax_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2767{
2768  std::pair<_ForwardIterator, _ForwardIterator> __result(__first, __first);
2769  if (__first != __last)
2770  {
2771      if (++__first != __last)
2772      {
2773          if (__comp(*__first, *__result.first))
2774              __result.first = __first;
2775          else
2776              __result.second = __first;
2777          while (++__first != __last)
2778          {
2779              _ForwardIterator __i = __first;
2780              if (++__first == __last)
2781              {
2782                  if (__comp(*__i, *__result.first))
2783                      __result.first = __i;
2784                  else if (!__comp(*__i, *__result.second))
2785                      __result.second = __i;
2786                  break;
2787              }
2788              else
2789              {
2790                  if (__comp(*__first, *__i))
2791                  {
2792                      if (__comp(*__first, *__result.first))
2793                          __result.first = __first;
2794                      if (!__comp(*__i, *__result.second))
2795                          __result.second = __i;
2796                  }
2797                  else
2798                  {
2799                      if (__comp(*__i, *__result.first))
2800                          __result.first = __i;
2801                      if (!__comp(*__first, *__result.second))
2802                          __result.second = __first;
2803                  }
2804              }
2805          }
2806      }
2807  }
2808  return __result;
2809}
2810
2811template <class _ForwardIterator>
2812inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2813std::pair<_ForwardIterator, _ForwardIterator>
2814minmax_element(_ForwardIterator __first, _ForwardIterator __last)
2815{
2816    return _VSTD::minmax_element(__first, __last,
2817              __less<typename iterator_traits<_ForwardIterator>::value_type>());
2818}
2819
2820// minmax
2821
2822template<class _Tp, class _Compare>
2823inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2824pair<const _Tp&, const _Tp&>
2825minmax(const _Tp& __a, const _Tp& __b, _Compare __comp)
2826{
2827    return __comp(__b, __a) ? pair<const _Tp&, const _Tp&>(__b, __a) :
2828                              pair<const _Tp&, const _Tp&>(__a, __b);
2829}
2830
2831template<class _Tp>
2832inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2833pair<const _Tp&, const _Tp&>
2834minmax(const _Tp& __a, const _Tp& __b)
2835{
2836    return _VSTD::minmax(__a, __b, __less<_Tp>());
2837}
2838
2839#ifndef _LIBCPP_CXX03_LANG
2840
2841template<class _Tp, class _Compare>
2842inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2843pair<_Tp, _Tp>
2844minmax(initializer_list<_Tp> __t, _Compare __comp)
2845{
2846    typedef typename initializer_list<_Tp>::const_iterator _Iter;
2847    _Iter __first = __t.begin();
2848    _Iter __last  = __t.end();
2849    std::pair<_Tp, _Tp> __result(*__first, *__first);
2850
2851    ++__first;
2852    if (__t.size() % 2 == 0)
2853    {
2854        if (__comp(*__first,  __result.first))
2855            __result.first  = *__first;
2856        else
2857            __result.second = *__first;
2858        ++__first;
2859    }
2860
2861    while (__first != __last)
2862    {
2863        _Tp __prev = *__first++;
2864        if (__comp(*__first, __prev)) {
2865            if ( __comp(*__first, __result.first)) __result.first  = *__first;
2866            if (!__comp(__prev, __result.second))  __result.second = __prev;
2867            }
2868        else {
2869            if ( __comp(__prev, __result.first))    __result.first  = __prev;
2870            if (!__comp(*__first, __result.second)) __result.second = *__first;
2871            }
2872
2873        __first++;
2874    }
2875    return __result;
2876}
2877
2878template<class _Tp>
2879inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2880pair<_Tp, _Tp>
2881minmax(initializer_list<_Tp> __t)
2882{
2883    return _VSTD::minmax(__t, __less<_Tp>());
2884}
2885
2886#endif  // _LIBCPP_CXX03_LANG
2887
2888// random_shuffle
2889
2890// __independent_bits_engine
2891
2892template <unsigned long long _Xp, size_t _Rp>
2893struct __log2_imp
2894{
2895    static const size_t value = _Xp & ((unsigned long long)(1) << _Rp) ? _Rp
2896                                           : __log2_imp<_Xp, _Rp - 1>::value;
2897};
2898
2899template <unsigned long long _Xp>
2900struct __log2_imp<_Xp, 0>
2901{
2902    static const size_t value = 0;
2903};
2904
2905template <size_t _Rp>
2906struct __log2_imp<0, _Rp>
2907{
2908    static const size_t value = _Rp + 1;
2909};
2910
2911template <class _UI, _UI _Xp>
2912struct __log2
2913{
2914    static const size_t value = __log2_imp<_Xp,
2915                                         sizeof(_UI) * __CHAR_BIT__ - 1>::value;
2916};
2917
2918template<class _Engine, class _UIntType>
2919class __independent_bits_engine
2920{
2921public:
2922    // types
2923    typedef _UIntType result_type;
2924
2925private:
2926    typedef typename _Engine::result_type _Engine_result_type;
2927    typedef typename conditional
2928        <
2929            sizeof(_Engine_result_type) <= sizeof(result_type),
2930                result_type,
2931                _Engine_result_type
2932        >::type _Working_result_type;
2933
2934    _Engine& __e_;
2935    size_t __w_;
2936    size_t __w0_;
2937    size_t __n_;
2938    size_t __n0_;
2939    _Working_result_type __y0_;
2940    _Working_result_type __y1_;
2941    _Engine_result_type __mask0_;
2942    _Engine_result_type __mask1_;
2943
2944#ifdef _LIBCPP_CXX03_LANG
2945    static const _Working_result_type _Rp = _Engine::_Max - _Engine::_Min
2946                                          + _Working_result_type(1);
2947#else
2948    static _LIBCPP_CONSTEXPR const _Working_result_type _Rp = _Engine::max() - _Engine::min()
2949                                                      + _Working_result_type(1);
2950#endif
2951    static _LIBCPP_CONSTEXPR const size_t __m = __log2<_Working_result_type, _Rp>::value;
2952    static _LIBCPP_CONSTEXPR const size_t _WDt = numeric_limits<_Working_result_type>::digits;
2953    static _LIBCPP_CONSTEXPR const size_t _EDt = numeric_limits<_Engine_result_type>::digits;
2954
2955public:
2956    // constructors and seeding functions
2957    __independent_bits_engine(_Engine& __e, size_t __w);
2958
2959    // generating functions
2960    result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
2961
2962private:
2963    result_type __eval(false_type);
2964    result_type __eval(true_type);
2965};
2966
2967template<class _Engine, class _UIntType>
2968__independent_bits_engine<_Engine, _UIntType>
2969    ::__independent_bits_engine(_Engine& __e, size_t __w)
2970        : __e_(__e),
2971          __w_(__w)
2972{
2973    __n_ = __w_ / __m + (__w_ % __m != 0);
2974    __w0_ = __w_ / __n_;
2975    if (_Rp == 0)
2976        __y0_ = _Rp;
2977    else if (__w0_ < _WDt)
2978        __y0_ = (_Rp >> __w0_) << __w0_;
2979    else
2980        __y0_ = 0;
2981    if (_Rp - __y0_ > __y0_ / __n_)
2982    {
2983        ++__n_;
2984        __w0_ = __w_ / __n_;
2985        if (__w0_ < _WDt)
2986            __y0_ = (_Rp >> __w0_) << __w0_;
2987        else
2988            __y0_ = 0;
2989    }
2990    __n0_ = __n_ - __w_ % __n_;
2991    if (__w0_ < _WDt - 1)
2992        __y1_ = (_Rp >> (__w0_ + 1)) << (__w0_ + 1);
2993    else
2994        __y1_ = 0;
2995    __mask0_ = __w0_ > 0 ? _Engine_result_type(~0) >> (_EDt - __w0_) :
2996                          _Engine_result_type(0);
2997    __mask1_ = __w0_ < _EDt - 1 ?
2998                               _Engine_result_type(~0) >> (_EDt - (__w0_ + 1)) :
2999                               _Engine_result_type(~0);
3000}
3001
3002template<class _Engine, class _UIntType>
3003inline
3004_UIntType
3005__independent_bits_engine<_Engine, _UIntType>::__eval(false_type)
3006{
3007    return static_cast<result_type>(__e_() & __mask0_);
3008}
3009
3010template<class _Engine, class _UIntType>
3011_UIntType
3012__independent_bits_engine<_Engine, _UIntType>::__eval(true_type)
3013{
3014    result_type _Sp = 0;
3015    for (size_t __k = 0; __k < __n0_; ++__k)
3016    {
3017        _Engine_result_type __u;
3018        do
3019        {
3020            __u = __e_() - _Engine::min();
3021        } while (__u >= __y0_);
3022        if (__w0_ < _WDt)
3023            _Sp <<= __w0_;
3024        else
3025            _Sp = 0;
3026        _Sp += __u & __mask0_;
3027    }
3028    for (size_t __k = __n0_; __k < __n_; ++__k)
3029    {
3030        _Engine_result_type __u;
3031        do
3032        {
3033            __u = __e_() - _Engine::min();
3034        } while (__u >= __y1_);
3035        if (__w0_ < _WDt - 1)
3036            _Sp <<= __w0_ + 1;
3037        else
3038            _Sp = 0;
3039        _Sp += __u & __mask1_;
3040    }
3041    return _Sp;
3042}
3043
3044// uniform_int_distribution
3045
3046template<class _IntType = int>
3047class uniform_int_distribution
3048{
3049public:
3050    // types
3051    typedef _IntType result_type;
3052
3053    class param_type
3054    {
3055        result_type __a_;
3056        result_type __b_;
3057    public:
3058        typedef uniform_int_distribution distribution_type;
3059
3060        explicit param_type(result_type __a = 0,
3061                            result_type __b = numeric_limits<result_type>::max())
3062            : __a_(__a), __b_(__b) {}
3063
3064        result_type a() const {return __a_;}
3065        result_type b() const {return __b_;}
3066
3067        friend bool operator==(const param_type& __x, const param_type& __y)
3068            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
3069        friend bool operator!=(const param_type& __x, const param_type& __y)
3070            {return !(__x == __y);}
3071    };
3072
3073private:
3074    param_type __p_;
3075
3076public:
3077    // constructors and reset functions
3078    explicit uniform_int_distribution(result_type __a = 0,
3079                                      result_type __b = numeric_limits<result_type>::max())
3080        : __p_(param_type(__a, __b)) {}
3081    explicit uniform_int_distribution(const param_type& __p) : __p_(__p) {}
3082    void reset() {}
3083
3084    // generating functions
3085    template<class _URNG> result_type operator()(_URNG& __g)
3086        {return (*this)(__g, __p_);}
3087    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
3088
3089    // property functions
3090    result_type a() const {return __p_.a();}
3091    result_type b() const {return __p_.b();}
3092
3093    param_type param() const {return __p_;}
3094    void param(const param_type& __p) {__p_ = __p;}
3095
3096    result_type min() const {return a();}
3097    result_type max() const {return b();}
3098
3099    friend bool operator==(const uniform_int_distribution& __x,
3100                           const uniform_int_distribution& __y)
3101        {return __x.__p_ == __y.__p_;}
3102    friend bool operator!=(const uniform_int_distribution& __x,
3103                           const uniform_int_distribution& __y)
3104            {return !(__x == __y);}
3105};
3106
3107template<class _IntType>
3108template<class _URNG>
3109typename uniform_int_distribution<_IntType>::result_type
3110uniform_int_distribution<_IntType>::operator()(_URNG& __g, const param_type& __p)
3111{
3112    typedef typename conditional<sizeof(result_type) <= sizeof(uint32_t),
3113                                            uint32_t, uint64_t>::type _UIntType;
3114    const _UIntType _Rp = __p.b() - __p.a() + _UIntType(1);
3115    if (_Rp == 1)
3116        return __p.a();
3117    const size_t _Dt = numeric_limits<_UIntType>::digits;
3118    typedef __independent_bits_engine<_URNG, _UIntType> _Eng;
3119    if (_Rp == 0)
3120        return static_cast<result_type>(_Eng(__g, _Dt)());
3121    size_t __w = _Dt - __clz(_Rp) - 1;
3122    if ((_Rp & (std::numeric_limits<_UIntType>::max() >> (_Dt - __w))) != 0)
3123        ++__w;
3124    _Eng __e(__g, __w);
3125    _UIntType __u;
3126    do
3127    {
3128        __u = __e();
3129    } while (__u >= _Rp);
3130    return static_cast<result_type>(__u + __p.a());
3131}
3132
3133#if _LIBCPP_STD_VER <= 14 || defined(_LIBCPP_ENABLE_CXX17_REMOVED_RANDOM_SHUFFLE) \
3134  || defined(_LIBCPP_BUILDING_LIBRARY)
3135class _LIBCPP_TYPE_VIS __rs_default;
3136
3137_LIBCPP_FUNC_VIS __rs_default __rs_get();
3138
3139class _LIBCPP_TYPE_VIS __rs_default
3140{
3141    static unsigned __c_;
3142
3143    __rs_default();
3144public:
3145    typedef uint_fast32_t result_type;
3146
3147    static const result_type _Min = 0;
3148    static const result_type _Max = 0xFFFFFFFF;
3149
3150    __rs_default(const __rs_default&);
3151    ~__rs_default();
3152
3153    result_type operator()();
3154
3155    static _LIBCPP_CONSTEXPR result_type min() {return _Min;}
3156    static _LIBCPP_CONSTEXPR result_type max() {return _Max;}
3157
3158    friend _LIBCPP_FUNC_VIS __rs_default __rs_get();
3159};
3160
3161_LIBCPP_FUNC_VIS __rs_default __rs_get();
3162
3163template <class _RandomAccessIterator>
3164void
3165random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)
3166{
3167    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3168    typedef uniform_int_distribution<ptrdiff_t> _Dp;
3169    typedef typename _Dp::param_type _Pp;
3170    difference_type __d = __last - __first;
3171    if (__d > 1)
3172    {
3173        _Dp __uid;
3174        __rs_default __g = __rs_get();
3175        for (--__last, --__d; __first < __last; ++__first, --__d)
3176        {
3177            difference_type __i = __uid(__g, _Pp(0, __d));
3178            if (__i != difference_type(0))
3179                swap(*__first, *(__first + __i));
3180        }
3181    }
3182}
3183
3184template <class _RandomAccessIterator, class _RandomNumberGenerator>
3185void
3186random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
3187#ifndef _LIBCPP_CXX03_LANG
3188               _RandomNumberGenerator&& __rand)
3189#else
3190               _RandomNumberGenerator& __rand)
3191#endif
3192{
3193    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3194    difference_type __d = __last - __first;
3195    if (__d > 1)
3196    {
3197        for (--__last; __first < __last; ++__first, --__d)
3198        {
3199            difference_type __i = __rand(__d);
3200            swap(*__first, *(__first + __i));
3201        }
3202    }
3203}
3204#endif
3205
3206template <class _PopulationIterator, class _SampleIterator, class _Distance,
3207          class _UniformRandomNumberGenerator>
3208_LIBCPP_INLINE_VISIBILITY
3209_SampleIterator __sample(_PopulationIterator __first,
3210                         _PopulationIterator __last, _SampleIterator __output,
3211                         _Distance __n,
3212                         _UniformRandomNumberGenerator & __g,
3213                         input_iterator_tag) {
3214
3215  _Distance __k = 0;
3216  for (; __first != __last && __k < __n; ++__first, (void)++__k)
3217    __output[__k] = *__first;
3218  _Distance __sz = __k;
3219  for (; __first != __last; ++__first, (void)++__k) {
3220    _Distance __r = _VSTD::uniform_int_distribution<_Distance>(0, __k)(__g);
3221    if (__r < __sz)
3222      __output[__r] = *__first;
3223  }
3224  return __output + _VSTD::min(__n, __k);
3225}
3226
3227template <class _PopulationIterator, class _SampleIterator, class _Distance,
3228          class _UniformRandomNumberGenerator>
3229_LIBCPP_INLINE_VISIBILITY
3230_SampleIterator __sample(_PopulationIterator __first,
3231                         _PopulationIterator __last, _SampleIterator __output,
3232                         _Distance __n,
3233                         _UniformRandomNumberGenerator& __g,
3234                         forward_iterator_tag) {
3235  _Distance __unsampled_sz = _VSTD::distance(__first, __last);
3236  for (__n = _VSTD::min(__n, __unsampled_sz); __n != 0; ++__first) {
3237    _Distance __r =
3238        _VSTD::uniform_int_distribution<_Distance>(0, --__unsampled_sz)(__g);
3239    if (__r < __n) {
3240      *__output++ = *__first;
3241      --__n;
3242    }
3243  }
3244  return __output;
3245}
3246
3247template <class _PopulationIterator, class _SampleIterator, class _Distance,
3248          class _UniformRandomNumberGenerator>
3249_LIBCPP_INLINE_VISIBILITY
3250_SampleIterator __sample(_PopulationIterator __first,
3251                         _PopulationIterator __last, _SampleIterator __output,
3252                         _Distance __n, _UniformRandomNumberGenerator& __g) {
3253  typedef typename iterator_traits<_PopulationIterator>::iterator_category
3254        _PopCategory;
3255  typedef typename iterator_traits<_PopulationIterator>::difference_type
3256        _Difference;
3257  static_assert(__is_forward_iterator<_PopulationIterator>::value ||
3258                __is_random_access_iterator<_SampleIterator>::value,
3259                "SampleIterator must meet the requirements of RandomAccessIterator");
3260  typedef typename common_type<_Distance, _Difference>::type _CommonType;
3261  _LIBCPP_ASSERT(__n >= 0, "N must be a positive number.");
3262  return _VSTD::__sample(
3263      __first, __last, __output, _CommonType(__n),
3264      __g, _PopCategory());
3265}
3266
3267#if _LIBCPP_STD_VER > 14
3268template <class _PopulationIterator, class _SampleIterator, class _Distance,
3269          class _UniformRandomNumberGenerator>
3270inline _LIBCPP_INLINE_VISIBILITY
3271_SampleIterator sample(_PopulationIterator __first,
3272                       _PopulationIterator __last, _SampleIterator __output,
3273                       _Distance __n, _UniformRandomNumberGenerator&& __g) {
3274    return _VSTD::__sample(__first, __last, __output, __n, __g);
3275}
3276#endif // _LIBCPP_STD_VER > 14
3277
3278template<class _RandomAccessIterator, class _UniformRandomNumberGenerator>
3279    void shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
3280#ifndef _LIBCPP_CXX03_LANG
3281                 _UniformRandomNumberGenerator&& __g)
3282#else
3283                 _UniformRandomNumberGenerator& __g)
3284#endif
3285{
3286    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3287    typedef uniform_int_distribution<ptrdiff_t> _Dp;
3288    typedef typename _Dp::param_type _Pp;
3289    difference_type __d = __last - __first;
3290    if (__d > 1)
3291    {
3292        _Dp __uid;
3293        for (--__last, --__d; __first < __last; ++__first, --__d)
3294        {
3295            difference_type __i = __uid(__g, _Pp(0, __d));
3296            if (__i != difference_type(0))
3297                swap(*__first, *(__first + __i));
3298        }
3299    }
3300}
3301
3302template <class _InputIterator, class _Predicate>
3303bool
3304is_partitioned(_InputIterator __first, _InputIterator __last, _Predicate __pred)
3305{
3306    for (; __first != __last; ++__first)
3307        if (!__pred(*__first))
3308            break;
3309    if ( __first == __last )
3310        return true;
3311    ++__first;
3312    for (; __first != __last; ++__first)
3313        if (__pred(*__first))
3314            return false;
3315    return true;
3316}
3317
3318// partition
3319
3320template <class _Predicate, class _ForwardIterator>
3321_ForwardIterator
3322__partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, forward_iterator_tag)
3323{
3324    while (true)
3325    {
3326        if (__first == __last)
3327            return __first;
3328        if (!__pred(*__first))
3329            break;
3330        ++__first;
3331    }
3332    for (_ForwardIterator __p = __first; ++__p != __last;)
3333    {
3334        if (__pred(*__p))
3335        {
3336            swap(*__first, *__p);
3337            ++__first;
3338        }
3339    }
3340    return __first;
3341}
3342
3343template <class _Predicate, class _BidirectionalIterator>
3344_BidirectionalIterator
3345__partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
3346            bidirectional_iterator_tag)
3347{
3348    while (true)
3349    {
3350        while (true)
3351        {
3352            if (__first == __last)
3353                return __first;
3354            if (!__pred(*__first))
3355                break;
3356            ++__first;
3357        }
3358        do
3359        {
3360            if (__first == --__last)
3361                return __first;
3362        } while (!__pred(*__last));
3363        swap(*__first, *__last);
3364        ++__first;
3365    }
3366}
3367
3368template <class _ForwardIterator, class _Predicate>
3369inline _LIBCPP_INLINE_VISIBILITY
3370_ForwardIterator
3371partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
3372{
3373    return _VSTD::__partition<typename add_lvalue_reference<_Predicate>::type>
3374                            (__first, __last, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
3375}
3376
3377// partition_copy
3378
3379template <class _InputIterator, class _OutputIterator1,
3380          class _OutputIterator2, class _Predicate>
3381pair<_OutputIterator1, _OutputIterator2>
3382partition_copy(_InputIterator __first, _InputIterator __last,
3383               _OutputIterator1 __out_true, _OutputIterator2 __out_false,
3384               _Predicate __pred)
3385{
3386    for (; __first != __last; ++__first)
3387    {
3388        if (__pred(*__first))
3389        {
3390            *__out_true = *__first;
3391            ++__out_true;
3392        }
3393        else
3394        {
3395            *__out_false = *__first;
3396            ++__out_false;
3397        }
3398    }
3399    return pair<_OutputIterator1, _OutputIterator2>(__out_true, __out_false);
3400}
3401
3402// partition_point
3403
3404template<class _ForwardIterator, class _Predicate>
3405_ForwardIterator
3406partition_point(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
3407{
3408    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
3409    difference_type __len = _VSTD::distance(__first, __last);
3410    while (__len != 0)
3411    {
3412        difference_type __l2 = __len / 2;
3413        _ForwardIterator __m = __first;
3414        _VSTD::advance(__m, __l2);
3415        if (__pred(*__m))
3416        {
3417            __first = ++__m;
3418            __len -= __l2 + 1;
3419        }
3420        else
3421            __len = __l2;
3422    }
3423    return __first;
3424}
3425
3426// stable_partition
3427
3428template <class _Predicate, class _ForwardIterator, class _Distance, class _Pair>
3429_ForwardIterator
3430__stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred,
3431                   _Distance __len, _Pair __p, forward_iterator_tag __fit)
3432{
3433    // *__first is known to be false
3434    // __len >= 1
3435    if (__len == 1)
3436        return __first;
3437    if (__len == 2)
3438    {
3439        _ForwardIterator __m = __first;
3440        if (__pred(*++__m))
3441        {
3442            swap(*__first, *__m);
3443            return __m;
3444        }
3445        return __first;
3446    }
3447    if (__len <= __p.second)
3448    {   // The buffer is big enough to use
3449        typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
3450        __destruct_n __d(0);
3451        unique_ptr<value_type, __destruct_n&> __h(__p.first, __d);
3452        // Move the falses into the temporary buffer, and the trues to the front of the line
3453        // Update __first to always point to the end of the trues
3454        value_type* __t = __p.first;
3455        ::new(__t) value_type(_VSTD::move(*__first));
3456        __d.__incr((value_type*)0);
3457        ++__t;
3458        _ForwardIterator __i = __first;
3459        while (++__i != __last)
3460        {
3461            if (__pred(*__i))
3462            {
3463                *__first = _VSTD::move(*__i);
3464                ++__first;
3465            }
3466            else
3467            {
3468                ::new(__t) value_type(_VSTD::move(*__i));
3469                __d.__incr((value_type*)0);
3470                ++__t;
3471            }
3472        }
3473        // All trues now at start of range, all falses in buffer
3474        // Move falses back into range, but don't mess up __first which points to first false
3475        __i = __first;
3476        for (value_type* __t2 = __p.first; __t2 < __t; ++__t2, ++__i)
3477            *__i = _VSTD::move(*__t2);
3478        // __h destructs moved-from values out of the temp buffer, but doesn't deallocate buffer
3479        return __first;
3480    }
3481    // Else not enough buffer, do in place
3482    // __len >= 3
3483    _ForwardIterator __m = __first;
3484    _Distance __len2 = __len / 2;  // __len2 >= 2
3485    _VSTD::advance(__m, __len2);
3486    // recurse on [__first, __m), *__first know to be false
3487    // F?????????????????
3488    // f       m         l
3489    typedef typename add_lvalue_reference<_Predicate>::type _PredRef;
3490    _ForwardIterator __first_false = __stable_partition<_PredRef>(__first, __m, __pred, __len2, __p, __fit);
3491    // TTTFFFFF??????????
3492    // f  ff   m         l
3493    // recurse on [__m, __last], except increase __m until *(__m) is false, *__last know to be true
3494    _ForwardIterator __m1 = __m;
3495    _ForwardIterator __second_false = __last;
3496    _Distance __len_half = __len - __len2;
3497    while (__pred(*__m1))
3498    {
3499        if (++__m1 == __last)
3500            goto __second_half_done;
3501        --__len_half;
3502    }
3503    // TTTFFFFFTTTF??????
3504    // f  ff   m  m1     l
3505    __second_false = __stable_partition<_PredRef>(__m1, __last, __pred, __len_half, __p, __fit);
3506__second_half_done:
3507    // TTTFFFFFTTTTTFFFFF
3508    // f  ff   m    sf   l
3509    return _VSTD::rotate(__first_false, __m, __second_false);
3510    // TTTTTTTTFFFFFFFFFF
3511    //         |
3512}
3513
3514struct __return_temporary_buffer
3515{
3516    template <class _Tp>
3517    _LIBCPP_INLINE_VISIBILITY void operator()(_Tp* __p) const {_VSTD::return_temporary_buffer(__p);}
3518};
3519
3520template <class _Predicate, class _ForwardIterator>
3521_ForwardIterator
3522__stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred,
3523                   forward_iterator_tag)
3524{
3525    const unsigned __alloc_limit = 3;  // might want to make this a function of trivial assignment
3526    // Either prove all true and return __first or point to first false
3527    while (true)
3528    {
3529        if (__first == __last)
3530            return __first;
3531        if (!__pred(*__first))
3532            break;
3533        ++__first;
3534    }
3535    // We now have a reduced range [__first, __last)
3536    // *__first is known to be false
3537    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
3538    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
3539    difference_type __len = _VSTD::distance(__first, __last);
3540    pair<value_type*, ptrdiff_t> __p(0, 0);
3541    unique_ptr<value_type, __return_temporary_buffer> __h;
3542    if (__len >= __alloc_limit)
3543    {
3544        __p = _VSTD::get_temporary_buffer<value_type>(__len);
3545        __h.reset(__p.first);
3546    }
3547    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
3548                             (__first, __last, __pred, __len, __p, forward_iterator_tag());
3549}
3550
3551template <class _Predicate, class _BidirectionalIterator, class _Distance, class _Pair>
3552_BidirectionalIterator
3553__stable_partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
3554                   _Distance __len, _Pair __p, bidirectional_iterator_tag __bit)
3555{
3556    // *__first is known to be false
3557    // *__last is known to be true
3558    // __len >= 2
3559    if (__len == 2)
3560    {
3561        swap(*__first, *__last);
3562        return __last;
3563    }
3564    if (__len == 3)
3565    {
3566        _BidirectionalIterator __m = __first;
3567        if (__pred(*++__m))
3568        {
3569            swap(*__first, *__m);
3570            swap(*__m, *__last);
3571            return __last;
3572        }
3573        swap(*__m, *__last);
3574        swap(*__first, *__m);
3575        return __m;
3576    }
3577    if (__len <= __p.second)
3578    {   // The buffer is big enough to use
3579        typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
3580        __destruct_n __d(0);
3581        unique_ptr<value_type, __destruct_n&> __h(__p.first, __d);
3582        // Move the falses into the temporary buffer, and the trues to the front of the line
3583        // Update __first to always point to the end of the trues
3584        value_type* __t = __p.first;
3585        ::new(__t) value_type(_VSTD::move(*__first));
3586        __d.__incr((value_type*)0);
3587        ++__t;
3588        _BidirectionalIterator __i = __first;
3589        while (++__i != __last)
3590        {
3591            if (__pred(*__i))
3592            {
3593                *__first = _VSTD::move(*__i);
3594                ++__first;
3595            }
3596            else
3597            {
3598                ::new(__t) value_type(_VSTD::move(*__i));
3599                __d.__incr((value_type*)0);
3600                ++__t;
3601            }
3602        }
3603        // move *__last, known to be true
3604        *__first = _VSTD::move(*__i);
3605        __i = ++__first;
3606        // All trues now at start of range, all falses in buffer
3607        // Move falses back into range, but don't mess up __first which points to first false
3608        for (value_type* __t2 = __p.first; __t2 < __t; ++__t2, ++__i)
3609            *__i = _VSTD::move(*__t2);
3610        // __h destructs moved-from values out of the temp buffer, but doesn't deallocate buffer
3611        return __first;
3612    }
3613    // Else not enough buffer, do in place
3614    // __len >= 4
3615    _BidirectionalIterator __m = __first;
3616    _Distance __len2 = __len / 2;  // __len2 >= 2
3617    _VSTD::advance(__m, __len2);
3618    // recurse on [__first, __m-1], except reduce __m-1 until *(__m-1) is true, *__first know to be false
3619    // F????????????????T
3620    // f       m        l
3621    _BidirectionalIterator __m1 = __m;
3622    _BidirectionalIterator __first_false = __first;
3623    _Distance __len_half = __len2;
3624    while (!__pred(*--__m1))
3625    {
3626        if (__m1 == __first)
3627            goto __first_half_done;
3628        --__len_half;
3629    }
3630    // F???TFFF?????????T
3631    // f   m1  m        l
3632    typedef typename add_lvalue_reference<_Predicate>::type _PredRef;
3633    __first_false = __stable_partition<_PredRef>(__first, __m1, __pred, __len_half, __p, __bit);
3634__first_half_done:
3635    // TTTFFFFF?????????T
3636    // f  ff   m        l
3637    // recurse on [__m, __last], except increase __m until *(__m) is false, *__last know to be true
3638    __m1 = __m;
3639    _BidirectionalIterator __second_false = __last;
3640    ++__second_false;
3641    __len_half = __len - __len2;
3642    while (__pred(*__m1))
3643    {
3644        if (++__m1 == __last)
3645            goto __second_half_done;
3646        --__len_half;
3647    }
3648    // TTTFFFFFTTTF?????T
3649    // f  ff   m  m1    l
3650    __second_false = __stable_partition<_PredRef>(__m1, __last, __pred, __len_half, __p, __bit);
3651__second_half_done:
3652    // TTTFFFFFTTTTTFFFFF
3653    // f  ff   m    sf  l
3654    return _VSTD::rotate(__first_false, __m, __second_false);
3655    // TTTTTTTTFFFFFFFFFF
3656    //         |
3657}
3658
3659template <class _Predicate, class _BidirectionalIterator>
3660_BidirectionalIterator
3661__stable_partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
3662                   bidirectional_iterator_tag)
3663{
3664    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
3665    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
3666    const difference_type __alloc_limit = 4;  // might want to make this a function of trivial assignment
3667    // Either prove all true and return __first or point to first false
3668    while (true)
3669    {
3670        if (__first == __last)
3671            return __first;
3672        if (!__pred(*__first))
3673            break;
3674        ++__first;
3675    }
3676    // __first points to first false, everything prior to __first is already set.
3677    // Either prove [__first, __last) is all false and return __first, or point __last to last true
3678    do
3679    {
3680        if (__first == --__last)
3681            return __first;
3682    } while (!__pred(*__last));
3683    // We now have a reduced range [__first, __last]
3684    // *__first is known to be false
3685    // *__last is known to be true
3686    // __len >= 2
3687    difference_type __len = _VSTD::distance(__first, __last) + 1;
3688    pair<value_type*, ptrdiff_t> __p(0, 0);
3689    unique_ptr<value_type, __return_temporary_buffer> __h;
3690    if (__len >= __alloc_limit)
3691    {
3692        __p = _VSTD::get_temporary_buffer<value_type>(__len);
3693        __h.reset(__p.first);
3694    }
3695    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
3696                             (__first, __last, __pred, __len, __p, bidirectional_iterator_tag());
3697}
3698
3699template <class _ForwardIterator, class _Predicate>
3700inline _LIBCPP_INLINE_VISIBILITY
3701_ForwardIterator
3702stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
3703{
3704    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
3705                             (__first, __last, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
3706}
3707
3708// is_sorted_until
3709
3710template <class _ForwardIterator, class _Compare>
3711_ForwardIterator
3712is_sorted_until(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
3713{
3714    if (__first != __last)
3715    {
3716        _ForwardIterator __i = __first;
3717        while (++__i != __last)
3718        {
3719            if (__comp(*__i, *__first))
3720                return __i;
3721            __first = __i;
3722        }
3723    }
3724    return __last;
3725}
3726
3727template<class _ForwardIterator>
3728inline _LIBCPP_INLINE_VISIBILITY
3729_ForwardIterator
3730is_sorted_until(_ForwardIterator __first, _ForwardIterator __last)
3731{
3732    return _VSTD::is_sorted_until(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
3733}
3734
3735// is_sorted
3736
3737template <class _ForwardIterator, class _Compare>
3738inline _LIBCPP_INLINE_VISIBILITY
3739bool
3740is_sorted(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
3741{
3742    return _VSTD::is_sorted_until(__first, __last, __comp) == __last;
3743}
3744
3745template<class _ForwardIterator>
3746inline _LIBCPP_INLINE_VISIBILITY
3747bool
3748is_sorted(_ForwardIterator __first, _ForwardIterator __last)
3749{
3750    return _VSTD::is_sorted(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
3751}
3752
3753// sort
3754
3755// stable, 2-3 compares, 0-2 swaps
3756
3757template <class _Compare, class _ForwardIterator>
3758unsigned
3759__sort3(_ForwardIterator __x, _ForwardIterator __y, _ForwardIterator __z, _Compare __c)
3760{
3761    unsigned __r = 0;
3762    if (!__c(*__y, *__x))          // if x <= y
3763    {
3764        if (!__c(*__z, *__y))      // if y <= z
3765            return __r;            // x <= y && y <= z
3766                                   // x <= y && y > z
3767        swap(*__y, *__z);          // x <= z && y < z
3768        __r = 1;
3769        if (__c(*__y, *__x))       // if x > y
3770        {
3771            swap(*__x, *__y);      // x < y && y <= z
3772            __r = 2;
3773        }
3774        return __r;                // x <= y && y < z
3775    }
3776    if (__c(*__z, *__y))           // x > y, if y > z
3777    {
3778        swap(*__x, *__z);          // x < y && y < z
3779        __r = 1;
3780        return __r;
3781    }
3782    swap(*__x, *__y);              // x > y && y <= z
3783    __r = 1;                       // x < y && x <= z
3784    if (__c(*__z, *__y))           // if y > z
3785    {
3786        swap(*__y, *__z);          // x <= y && y < z
3787        __r = 2;
3788    }
3789    return __r;
3790}                                  // x <= y && y <= z
3791
3792// stable, 3-6 compares, 0-5 swaps
3793
3794template <class _Compare, class _ForwardIterator>
3795unsigned
3796__sort4(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3,
3797            _ForwardIterator __x4, _Compare __c)
3798{
3799    unsigned __r = __sort3<_Compare>(__x1, __x2, __x3, __c);
3800    if (__c(*__x4, *__x3))
3801    {
3802        swap(*__x3, *__x4);
3803        ++__r;
3804        if (__c(*__x3, *__x2))
3805        {
3806            swap(*__x2, *__x3);
3807            ++__r;
3808            if (__c(*__x2, *__x1))
3809            {
3810                swap(*__x1, *__x2);
3811                ++__r;
3812            }
3813        }
3814    }
3815    return __r;
3816}
3817
3818// stable, 4-10 compares, 0-9 swaps
3819
3820template <class _Compare, class _ForwardIterator>
3821unsigned
3822__sort5(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3,
3823            _ForwardIterator __x4, _ForwardIterator __x5, _Compare __c)
3824{
3825    unsigned __r = __sort4<_Compare>(__x1, __x2, __x3, __x4, __c);
3826    if (__c(*__x5, *__x4))
3827    {
3828        swap(*__x4, *__x5);
3829        ++__r;
3830        if (__c(*__x4, *__x3))
3831        {
3832            swap(*__x3, *__x4);
3833            ++__r;
3834            if (__c(*__x3, *__x2))
3835            {
3836                swap(*__x2, *__x3);
3837                ++__r;
3838                if (__c(*__x2, *__x1))
3839                {
3840                    swap(*__x1, *__x2);
3841                    ++__r;
3842                }
3843            }
3844        }
3845    }
3846    return __r;
3847}
3848
3849// Assumes size > 0
3850template <class _Compare, class _BirdirectionalIterator>
3851void
3852__selection_sort(_BirdirectionalIterator __first, _BirdirectionalIterator __last, _Compare __comp)
3853{
3854    _BirdirectionalIterator __lm1 = __last;
3855    for (--__lm1; __first != __lm1; ++__first)
3856    {
3857        _BirdirectionalIterator __i = _VSTD::min_element<_BirdirectionalIterator,
3858                                                        typename add_lvalue_reference<_Compare>::type>
3859                                                       (__first, __last, __comp);
3860        if (__i != __first)
3861            swap(*__first, *__i);
3862    }
3863}
3864
3865template <class _Compare, class _BirdirectionalIterator>
3866void
3867__insertion_sort(_BirdirectionalIterator __first, _BirdirectionalIterator __last, _Compare __comp)
3868{
3869    typedef typename iterator_traits<_BirdirectionalIterator>::value_type value_type;
3870    if (__first != __last)
3871    {
3872        _BirdirectionalIterator __i = __first;
3873        for (++__i; __i != __last; ++__i)
3874        {
3875            _BirdirectionalIterator __j = __i;
3876            value_type __t(_VSTD::move(*__j));
3877            for (_BirdirectionalIterator __k = __i; __k != __first && __comp(__t,  *--__k); --__j)
3878                *__j = _VSTD::move(*__k);
3879            *__j = _VSTD::move(__t);
3880        }
3881    }
3882}
3883
3884template <class _Compare, class _RandomAccessIterator>
3885void
3886__insertion_sort_3(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
3887{
3888    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
3889    _RandomAccessIterator __j = __first+2;
3890    __sort3<_Compare>(__first, __first+1, __j, __comp);
3891    for (_RandomAccessIterator __i = __j+1; __i != __last; ++__i)
3892    {
3893        if (__comp(*__i, *__j))
3894        {
3895            value_type __t(_VSTD::move(*__i));
3896            _RandomAccessIterator __k = __j;
3897            __j = __i;
3898            do
3899            {
3900                *__j = _VSTD::move(*__k);
3901                __j = __k;
3902            } while (__j != __first && __comp(__t, *--__k));
3903            *__j = _VSTD::move(__t);
3904        }
3905        __j = __i;
3906    }
3907}
3908
3909template <class _Compare, class _RandomAccessIterator>
3910bool
3911__insertion_sort_incomplete(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
3912{
3913    switch (__last - __first)
3914    {
3915    case 0:
3916    case 1:
3917        return true;
3918    case 2:
3919        if (__comp(*--__last, *__first))
3920            swap(*__first, *__last);
3921        return true;
3922    case 3:
3923        _VSTD::__sort3<_Compare>(__first, __first+1, --__last, __comp);
3924        return true;
3925    case 4:
3926        _VSTD::__sort4<_Compare>(__first, __first+1, __first+2, --__last, __comp);
3927        return true;
3928    case 5:
3929        _VSTD::__sort5<_Compare>(__first, __first+1, __first+2, __first+3, --__last, __comp);
3930        return true;
3931    }
3932    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
3933    _RandomAccessIterator __j = __first+2;
3934    __sort3<_Compare>(__first, __first+1, __j, __comp);
3935    const unsigned __limit = 8;
3936    unsigned __count = 0;
3937    for (_RandomAccessIterator __i = __j+1; __i != __last; ++__i)
3938    {
3939        if (__comp(*__i, *__j))
3940        {
3941            value_type __t(_VSTD::move(*__i));
3942            _RandomAccessIterator __k = __j;
3943            __j = __i;
3944            do
3945            {
3946                *__j = _VSTD::move(*__k);
3947                __j = __k;
3948            } while (__j != __first && __comp(__t, *--__k));
3949            *__j = _VSTD::move(__t);
3950            if (++__count == __limit)
3951                return ++__i == __last;
3952        }
3953        __j = __i;
3954    }
3955    return true;
3956}
3957
3958template <class _Compare, class _BirdirectionalIterator>
3959void
3960__insertion_sort_move(_BirdirectionalIterator __first1, _BirdirectionalIterator __last1,
3961                      typename iterator_traits<_BirdirectionalIterator>::value_type* __first2, _Compare __comp)
3962{
3963    typedef typename iterator_traits<_BirdirectionalIterator>::value_type value_type;
3964    if (__first1 != __last1)
3965    {
3966        __destruct_n __d(0);
3967        unique_ptr<value_type, __destruct_n&> __h(__first2, __d);
3968        value_type* __last2 = __first2;
3969        ::new(__last2) value_type(_VSTD::move(*__first1));
3970        __d.__incr((value_type*)0);
3971        for (++__last2; ++__first1 != __last1; ++__last2)
3972        {
3973            value_type* __j2 = __last2;
3974            value_type* __i2 = __j2;
3975            if (__comp(*__first1, *--__i2))
3976            {
3977                ::new(__j2) value_type(_VSTD::move(*__i2));
3978                __d.__incr((value_type*)0);
3979                for (--__j2; __i2 != __first2 && __comp(*__first1,  *--__i2); --__j2)
3980                    *__j2 = _VSTD::move(*__i2);
3981                *__j2 = _VSTD::move(*__first1);
3982            }
3983            else
3984            {
3985                ::new(__j2) value_type(_VSTD::move(*__first1));
3986                __d.__incr((value_type*)0);
3987            }
3988        }
3989        __h.release();
3990    }
3991}
3992
3993template <class _Compare, class _RandomAccessIterator>
3994void
3995__sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
3996{
3997    // _Compare is known to be a reference type
3998    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3999    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4000    const difference_type __limit = is_trivially_copy_constructible<value_type>::value &&
4001                                    is_trivially_copy_assignable<value_type>::value ? 30 : 6;
4002    while (true)
4003    {
4004    __restart:
4005        difference_type __len = __last - __first;
4006        switch (__len)
4007        {
4008        case 0:
4009        case 1:
4010            return;
4011        case 2:
4012            if (__comp(*--__last, *__first))
4013                swap(*__first, *__last);
4014            return;
4015        case 3:
4016            _VSTD::__sort3<_Compare>(__first, __first+1, --__last, __comp);
4017            return;
4018        case 4:
4019            _VSTD::__sort4<_Compare>(__first, __first+1, __first+2, --__last, __comp);
4020            return;
4021        case 5:
4022            _VSTD::__sort5<_Compare>(__first, __first+1, __first+2, __first+3, --__last, __comp);
4023            return;
4024        }
4025        if (__len <= __limit)
4026        {
4027            _VSTD::__insertion_sort_3<_Compare>(__first, __last, __comp);
4028            return;
4029        }
4030        // __len > 5
4031        _RandomAccessIterator __m = __first;
4032        _RandomAccessIterator __lm1 = __last;
4033        --__lm1;
4034        unsigned __n_swaps;
4035        {
4036        difference_type __delta;
4037        if (__len >= 1000)
4038        {
4039            __delta = __len/2;
4040            __m += __delta;
4041            __delta /= 2;
4042            __n_swaps = _VSTD::__sort5<_Compare>(__first, __first + __delta, __m, __m+__delta, __lm1, __comp);
4043        }
4044        else
4045        {
4046            __delta = __len/2;
4047            __m += __delta;
4048            __n_swaps = _VSTD::__sort3<_Compare>(__first, __m, __lm1, __comp);
4049        }
4050        }
4051        // *__m is median
4052        // partition [__first, __m) < *__m and *__m <= [__m, __last)
4053        // (this inhibits tossing elements equivalent to __m around unnecessarily)
4054        _RandomAccessIterator __i = __first;
4055        _RandomAccessIterator __j = __lm1;
4056        // j points beyond range to be tested, *__m is known to be <= *__lm1
4057        // The search going up is known to be guarded but the search coming down isn't.
4058        // Prime the downward search with a guard.
4059        if (!__comp(*__i, *__m))  // if *__first == *__m
4060        {
4061            // *__first == *__m, *__first doesn't go in first part
4062            // manually guard downward moving __j against __i
4063            while (true)
4064            {
4065                if (__i == --__j)
4066                {
4067                    // *__first == *__m, *__m <= all other elements
4068                    // Parition instead into [__first, __i) == *__first and *__first < [__i, __last)
4069                    ++__i;  // __first + 1
4070                    __j = __last;
4071                    if (!__comp(*__first, *--__j))  // we need a guard if *__first == *(__last-1)
4072                    {
4073                        while (true)
4074                        {
4075                            if (__i == __j)
4076                                return;  // [__first, __last) all equivalent elements
4077                            if (__comp(*__first, *__i))
4078                            {
4079                                swap(*__i, *__j);
4080                                ++__n_swaps;
4081                                ++__i;
4082                                break;
4083                            }
4084                            ++__i;
4085                        }
4086                    }
4087                    // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
4088                    if (__i == __j)
4089                        return;
4090                    while (true)
4091                    {
4092                        while (!__comp(*__first, *__i))
4093                            ++__i;
4094                        while (__comp(*__first, *--__j))
4095                            ;
4096                        if (__i >= __j)
4097                            break;
4098                        swap(*__i, *__j);
4099                        ++__n_swaps;
4100                        ++__i;
4101                    }
4102                    // [__first, __i) == *__first and *__first < [__i, __last)
4103                    // The first part is sorted, sort the secod part
4104                    // _VSTD::__sort<_Compare>(__i, __last, __comp);
4105                    __first = __i;
4106                    goto __restart;
4107                }
4108                if (__comp(*__j, *__m))
4109                {
4110                    swap(*__i, *__j);
4111                    ++__n_swaps;
4112                    break;  // found guard for downward moving __j, now use unguarded partition
4113                }
4114            }
4115        }
4116        // It is known that *__i < *__m
4117        ++__i;
4118        // j points beyond range to be tested, *__m is known to be <= *__lm1
4119        // if not yet partitioned...
4120        if (__i < __j)
4121        {
4122            // known that *(__i - 1) < *__m
4123            // known that __i <= __m
4124            while (true)
4125            {
4126                // __m still guards upward moving __i
4127                while (__comp(*__i, *__m))
4128                    ++__i;
4129                // It is now known that a guard exists for downward moving __j
4130                while (!__comp(*--__j, *__m))
4131                    ;
4132                if (__i > __j)
4133                    break;
4134                swap(*__i, *__j);
4135                ++__n_swaps;
4136                // It is known that __m != __j
4137                // If __m just moved, follow it
4138                if (__m == __i)
4139                    __m = __j;
4140                ++__i;
4141            }
4142        }
4143        // [__first, __i) < *__m and *__m <= [__i, __last)
4144        if (__i != __m && __comp(*__m, *__i))
4145        {
4146            swap(*__i, *__m);
4147            ++__n_swaps;
4148        }
4149        // [__first, __i) < *__i and *__i <= [__i+1, __last)
4150        // If we were given a perfect partition, see if insertion sort is quick...
4151        if (__n_swaps == 0)
4152        {
4153            bool __fs = _VSTD::__insertion_sort_incomplete<_Compare>(__first, __i, __comp);
4154            if (_VSTD::__insertion_sort_incomplete<_Compare>(__i+1, __last, __comp))
4155            {
4156                if (__fs)
4157                    return;
4158                __last = __i;
4159                continue;
4160            }
4161            else
4162            {
4163                if (__fs)
4164                {
4165                    __first = ++__i;
4166                    continue;
4167                }
4168            }
4169        }
4170        // sort smaller range with recursive call and larger with tail recursion elimination
4171        if (__i - __first < __last - __i)
4172        {
4173            _VSTD::__sort<_Compare>(__first, __i, __comp);
4174            // _VSTD::__sort<_Compare>(__i+1, __last, __comp);
4175            __first = ++__i;
4176        }
4177        else
4178        {
4179            _VSTD::__sort<_Compare>(__i+1, __last, __comp);
4180            // _VSTD::__sort<_Compare>(__first, __i, __comp);
4181            __last = __i;
4182        }
4183    }
4184}
4185
4186// This forwarder keeps the top call and the recursive calls using the same instantiation, forcing a reference _Compare
4187template <class _RandomAccessIterator, class _Compare>
4188inline _LIBCPP_INLINE_VISIBILITY
4189void
4190sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4191{
4192#ifdef _LIBCPP_DEBUG
4193    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4194    __debug_less<_Compare> __c(__comp);
4195    __sort<_Comp_ref>(__first, __last, __c);
4196#else  // _LIBCPP_DEBUG
4197    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4198    __sort<_Comp_ref>(__first, __last, __comp);
4199#endif  // _LIBCPP_DEBUG
4200}
4201
4202template <class _RandomAccessIterator>
4203inline _LIBCPP_INLINE_VISIBILITY
4204void
4205sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
4206{
4207    _VSTD::sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4208}
4209
4210template <class _Tp>
4211inline _LIBCPP_INLINE_VISIBILITY
4212void
4213sort(_Tp** __first, _Tp** __last)
4214{
4215    _VSTD::sort((size_t*)__first, (size_t*)__last, __less<size_t>());
4216}
4217
4218template <class _Tp>
4219inline _LIBCPP_INLINE_VISIBILITY
4220void
4221sort(__wrap_iter<_Tp*> __first, __wrap_iter<_Tp*> __last)
4222{
4223    _VSTD::sort(__first.base(), __last.base());
4224}
4225
4226template <class _Tp, class _Compare>
4227inline _LIBCPP_INLINE_VISIBILITY
4228void
4229sort(__wrap_iter<_Tp*> __first, __wrap_iter<_Tp*> __last, _Compare __comp)
4230{
4231    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4232    _VSTD::sort<_Tp*, _Comp_ref>(__first.base(), __last.base(), __comp);
4233}
4234
4235#ifdef _LIBCPP_MSVC
4236#pragma warning( push )
4237#pragma warning( disable: 4231)
4238#endif // _LIBCPP_MSVC
4239_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<char>&, char*>(char*, char*, __less<char>&))
4240_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&))
4241_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&))
4242_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&))
4243_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<short>&, short*>(short*, short*, __less<short>&))
4244_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&))
4245_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<int>&, int*>(int*, int*, __less<int>&))
4246_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&))
4247_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long>&, long*>(long*, long*, __less<long>&))
4248_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&))
4249_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long long>&, long long*>(long long*, long long*, __less<long long>&))
4250_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>&))
4251_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<float>&, float*>(float*, float*, __less<float>&))
4252_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<double>&, double*>(double*, double*, __less<double>&))
4253_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long double>&, long double*>(long double*, long double*, __less<long double>&))
4254
4255_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<char>&, char*>(char*, char*, __less<char>&))
4256_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&))
4257_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&))
4258_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&))
4259_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<short>&, short*>(short*, short*, __less<short>&))
4260_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&))
4261_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<int>&, int*>(int*, int*, __less<int>&))
4262_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&))
4263_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long>&, long*>(long*, long*, __less<long>&))
4264_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&))
4265_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long long>&, long long*>(long long*, long long*, __less<long long>&))
4266_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>&))
4267_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<float>&, float*>(float*, float*, __less<float>&))
4268_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<double>&, double*>(double*, double*, __less<double>&))
4269_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long double>&, long double*>(long double*, long double*, __less<long double>&))
4270
4271_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>&))
4272#ifdef _LIBCPP_MSVC
4273#pragma warning( pop )
4274#endif  // _LIBCPP_MSVC
4275
4276// lower_bound
4277
4278template <class _Compare, class _ForwardIterator, class _Tp>
4279_ForwardIterator
4280__lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4281{
4282    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
4283    difference_type __len = _VSTD::distance(__first, __last);
4284    while (__len != 0)
4285    {
4286        difference_type __l2 = __len / 2;
4287        _ForwardIterator __m = __first;
4288        _VSTD::advance(__m, __l2);
4289        if (__comp(*__m, __value_))
4290        {
4291            __first = ++__m;
4292            __len -= __l2 + 1;
4293        }
4294        else
4295            __len = __l2;
4296    }
4297    return __first;
4298}
4299
4300template <class _ForwardIterator, class _Tp, class _Compare>
4301inline _LIBCPP_INLINE_VISIBILITY
4302_ForwardIterator
4303lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4304{
4305#ifdef _LIBCPP_DEBUG
4306    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4307    __debug_less<_Compare> __c(__comp);
4308    return __lower_bound<_Comp_ref>(__first, __last, __value_, __c);
4309#else  // _LIBCPP_DEBUG
4310    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4311    return __lower_bound<_Comp_ref>(__first, __last, __value_, __comp);
4312#endif  // _LIBCPP_DEBUG
4313}
4314
4315template <class _ForwardIterator, class _Tp>
4316inline _LIBCPP_INLINE_VISIBILITY
4317_ForwardIterator
4318lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4319{
4320    return _VSTD::lower_bound(__first, __last, __value_,
4321                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
4322}
4323
4324// upper_bound
4325
4326template <class _Compare, class _ForwardIterator, class _Tp>
4327_ForwardIterator
4328__upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4329{
4330    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
4331    difference_type __len = _VSTD::distance(__first, __last);
4332    while (__len != 0)
4333    {
4334        difference_type __l2 = __len / 2;
4335        _ForwardIterator __m = __first;
4336        _VSTD::advance(__m, __l2);
4337        if (__comp(__value_, *__m))
4338            __len = __l2;
4339        else
4340        {
4341            __first = ++__m;
4342            __len -= __l2 + 1;
4343        }
4344    }
4345    return __first;
4346}
4347
4348template <class _ForwardIterator, class _Tp, class _Compare>
4349inline _LIBCPP_INLINE_VISIBILITY
4350_ForwardIterator
4351upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4352{
4353#ifdef _LIBCPP_DEBUG
4354    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4355    __debug_less<_Compare> __c(__comp);
4356    return __upper_bound<_Comp_ref>(__first, __last, __value_, __c);
4357#else  // _LIBCPP_DEBUG
4358    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4359    return __upper_bound<_Comp_ref>(__first, __last, __value_, __comp);
4360#endif  // _LIBCPP_DEBUG
4361}
4362
4363template <class _ForwardIterator, class _Tp>
4364inline _LIBCPP_INLINE_VISIBILITY
4365_ForwardIterator
4366upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4367{
4368    return _VSTD::upper_bound(__first, __last, __value_,
4369                             __less<_Tp, typename iterator_traits<_ForwardIterator>::value_type>());
4370}
4371
4372// equal_range
4373
4374template <class _Compare, class _ForwardIterator, class _Tp>
4375pair<_ForwardIterator, _ForwardIterator>
4376__equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4377{
4378    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
4379    difference_type __len = _VSTD::distance(__first, __last);
4380    while (__len != 0)
4381    {
4382        difference_type __l2 = __len / 2;
4383        _ForwardIterator __m = __first;
4384        _VSTD::advance(__m, __l2);
4385        if (__comp(*__m, __value_))
4386        {
4387            __first = ++__m;
4388            __len -= __l2 + 1;
4389        }
4390        else if (__comp(__value_, *__m))
4391        {
4392            __last = __m;
4393            __len = __l2;
4394        }
4395        else
4396        {
4397            _ForwardIterator __mp1 = __m;
4398            return pair<_ForwardIterator, _ForwardIterator>
4399                   (
4400                      __lower_bound<_Compare>(__first, __m, __value_, __comp),
4401                      __upper_bound<_Compare>(++__mp1, __last, __value_, __comp)
4402                   );
4403        }
4404    }
4405    return pair<_ForwardIterator, _ForwardIterator>(__first, __first);
4406}
4407
4408template <class _ForwardIterator, class _Tp, class _Compare>
4409inline _LIBCPP_INLINE_VISIBILITY
4410pair<_ForwardIterator, _ForwardIterator>
4411equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4412{
4413#ifdef _LIBCPP_DEBUG
4414    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4415    __debug_less<_Compare> __c(__comp);
4416    return __equal_range<_Comp_ref>(__first, __last, __value_, __c);
4417#else  // _LIBCPP_DEBUG
4418    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4419    return __equal_range<_Comp_ref>(__first, __last, __value_, __comp);
4420#endif  // _LIBCPP_DEBUG
4421}
4422
4423template <class _ForwardIterator, class _Tp>
4424inline _LIBCPP_INLINE_VISIBILITY
4425pair<_ForwardIterator, _ForwardIterator>
4426equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4427{
4428    return _VSTD::equal_range(__first, __last, __value_,
4429                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
4430}
4431
4432// binary_search
4433
4434template <class _Compare, class _ForwardIterator, class _Tp>
4435inline _LIBCPP_INLINE_VISIBILITY
4436bool
4437__binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4438{
4439    __first = __lower_bound<_Compare>(__first, __last, __value_, __comp);
4440    return __first != __last && !__comp(__value_, *__first);
4441}
4442
4443template <class _ForwardIterator, class _Tp, class _Compare>
4444inline _LIBCPP_INLINE_VISIBILITY
4445bool
4446binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4447{
4448#ifdef _LIBCPP_DEBUG
4449    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4450    __debug_less<_Compare> __c(__comp);
4451    return __binary_search<_Comp_ref>(__first, __last, __value_, __c);
4452#else  // _LIBCPP_DEBUG
4453    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4454    return __binary_search<_Comp_ref>(__first, __last, __value_, __comp);
4455#endif  // _LIBCPP_DEBUG
4456}
4457
4458template <class _ForwardIterator, class _Tp>
4459inline _LIBCPP_INLINE_VISIBILITY
4460bool
4461binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4462{
4463    return _VSTD::binary_search(__first, __last, __value_,
4464                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
4465}
4466
4467// merge
4468
4469template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
4470_OutputIterator
4471__merge(_InputIterator1 __first1, _InputIterator1 __last1,
4472        _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
4473{
4474    for (; __first1 != __last1; ++__result)
4475    {
4476        if (__first2 == __last2)
4477            return _VSTD::copy(__first1, __last1, __result);
4478        if (__comp(*__first2, *__first1))
4479        {
4480            *__result = *__first2;
4481            ++__first2;
4482        }
4483        else
4484        {
4485            *__result = *__first1;
4486            ++__first1;
4487        }
4488    }
4489    return _VSTD::copy(__first2, __last2, __result);
4490}
4491
4492template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
4493inline _LIBCPP_INLINE_VISIBILITY
4494_OutputIterator
4495merge(_InputIterator1 __first1, _InputIterator1 __last1,
4496      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
4497{
4498#ifdef _LIBCPP_DEBUG
4499    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4500    __debug_less<_Compare> __c(__comp);
4501    return _VSTD::__merge<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
4502#else  // _LIBCPP_DEBUG
4503    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4504    return _VSTD::__merge<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
4505#endif  // _LIBCPP_DEBUG
4506}
4507
4508template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
4509inline _LIBCPP_INLINE_VISIBILITY
4510_OutputIterator
4511merge(_InputIterator1 __first1, _InputIterator1 __last1,
4512      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
4513{
4514    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
4515    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
4516    return merge(__first1, __last1, __first2, __last2, __result, __less<__v1, __v2>());
4517}
4518
4519// inplace_merge
4520
4521template <class _Compare, class _InputIterator1, class _InputIterator2,
4522          class _OutputIterator>
4523void __half_inplace_merge(_InputIterator1 __first1, _InputIterator1 __last1,
4524                          _InputIterator2 __first2, _InputIterator2 __last2,
4525                          _OutputIterator __result, _Compare __comp)
4526{
4527    for (; __first1 != __last1; ++__result)
4528    {
4529        if (__first2 == __last2)
4530        {
4531            _VSTD::move(__first1, __last1, __result);
4532            return;
4533        }
4534
4535        if (__comp(*__first2, *__first1))
4536        {
4537            *__result = _VSTD::move(*__first2);
4538            ++__first2;
4539        }
4540        else
4541        {
4542            *__result = _VSTD::move(*__first1);
4543            ++__first1;
4544        }
4545    }
4546    // __first2 through __last2 are already in the right spot.
4547}
4548
4549template <class _Compare, class _BidirectionalIterator>
4550void
4551__buffered_inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
4552                _Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
4553                                 typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
4554                typename iterator_traits<_BidirectionalIterator>::value_type* __buff)
4555{
4556    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
4557    __destruct_n __d(0);
4558    unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
4559    if (__len1 <= __len2)
4560    {
4561        value_type* __p = __buff;
4562        for (_BidirectionalIterator __i = __first; __i != __middle; __d.__incr((value_type*)0), (void) ++__i, ++__p)
4563            ::new(__p) value_type(_VSTD::move(*__i));
4564        __half_inplace_merge(__buff, __p, __middle, __last, __first, __comp);
4565    }
4566    else
4567    {
4568        value_type* __p = __buff;
4569        for (_BidirectionalIterator __i = __middle; __i != __last; __d.__incr((value_type*)0), (void) ++__i, ++__p)
4570            ::new(__p) value_type(_VSTD::move(*__i));
4571        typedef reverse_iterator<_BidirectionalIterator> _RBi;
4572        typedef reverse_iterator<value_type*> _Rv;
4573        __half_inplace_merge(_Rv(__p), _Rv(__buff),
4574                             _RBi(__middle), _RBi(__first),
4575                             _RBi(__last), __negate<_Compare>(__comp));
4576    }
4577}
4578
4579template <class _Compare, class _BidirectionalIterator>
4580void
4581__inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
4582                _Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
4583                                 typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
4584                typename iterator_traits<_BidirectionalIterator>::value_type* __buff, ptrdiff_t __buff_size)
4585{
4586    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
4587    while (true)
4588    {
4589        // if __middle == __last, we're done
4590        if (__len2 == 0)
4591            return;
4592        if (__len1 <= __buff_size || __len2 <= __buff_size)
4593            return __buffered_inplace_merge<_Compare>
4594                   (__first, __middle, __last, __comp, __len1, __len2, __buff);
4595        // shrink [__first, __middle) as much as possible (with no moves), returning if it shrinks to 0
4596        for (; true; ++__first, (void) --__len1)
4597        {
4598            if (__len1 == 0)
4599                return;
4600            if (__comp(*__middle, *__first))
4601                break;
4602        }
4603        // __first < __middle < __last
4604        // *__first > *__middle
4605        // partition [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last) such that
4606        //     all elements in:
4607        //         [__first, __m1)  <= [__middle, __m2)
4608        //         [__middle, __m2) <  [__m1, __middle)
4609        //         [__m1, __middle) <= [__m2, __last)
4610        //     and __m1 or __m2 is in the middle of its range
4611        _BidirectionalIterator __m1;  // "median" of [__first, __middle)
4612        _BidirectionalIterator __m2;  // "median" of [__middle, __last)
4613        difference_type __len11;      // distance(__first, __m1)
4614        difference_type __len21;      // distance(__middle, __m2)
4615        // binary search smaller range
4616        if (__len1 < __len2)
4617        {   // __len >= 1, __len2 >= 2
4618            __len21 = __len2 / 2;
4619            __m2 = __middle;
4620            _VSTD::advance(__m2, __len21);
4621            __m1 = __upper_bound<_Compare>(__first, __middle, *__m2, __comp);
4622            __len11 = _VSTD::distance(__first, __m1);
4623        }
4624        else
4625        {
4626            if (__len1 == 1)
4627            {   // __len1 >= __len2 && __len2 > 0, therefore __len2 == 1
4628                // It is known *__first > *__middle
4629                swap(*__first, *__middle);
4630                return;
4631            }
4632            // __len1 >= 2, __len2 >= 1
4633            __len11 = __len1 / 2;
4634            __m1 = __first;
4635            _VSTD::advance(__m1, __len11);
4636            __m2 = __lower_bound<_Compare>(__middle, __last, *__m1, __comp);
4637            __len21 = _VSTD::distance(__middle, __m2);
4638        }
4639        difference_type __len12 = __len1 - __len11;  // distance(__m1, __middle)
4640        difference_type __len22 = __len2 - __len21;  // distance(__m2, __last)
4641        // [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last)
4642        // swap middle two partitions
4643        __middle = _VSTD::rotate(__m1, __middle, __m2);
4644        // __len12 and __len21 now have swapped meanings
4645        // merge smaller range with recurisve call and larger with tail recursion elimination
4646        if (__len11 + __len21 < __len12 + __len22)
4647        {
4648            __inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
4649//          __inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
4650            __first = __middle;
4651            __middle = __m2;
4652            __len1 = __len12;
4653            __len2 = __len22;
4654        }
4655        else
4656        {
4657            __inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
4658//          __inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
4659            __last = __middle;
4660            __middle = __m1;
4661            __len1 = __len11;
4662            __len2 = __len21;
4663        }
4664    }
4665}
4666
4667template <class _BidirectionalIterator, class _Compare>
4668inline _LIBCPP_INLINE_VISIBILITY
4669void
4670inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
4671              _Compare __comp)
4672{
4673    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
4674    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
4675    difference_type __len1 = _VSTD::distance(__first, __middle);
4676    difference_type __len2 = _VSTD::distance(__middle, __last);
4677    difference_type __buf_size = _VSTD::min(__len1, __len2);
4678    pair<value_type*, ptrdiff_t> __buf = _VSTD::get_temporary_buffer<value_type>(__buf_size);
4679    unique_ptr<value_type, __return_temporary_buffer> __h(__buf.first);
4680
4681#ifdef _LIBCPP_DEBUG
4682    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4683    __debug_less<_Compare> __c(__comp);
4684    return _VSTD::__inplace_merge<_Comp_ref>(__first, __middle, __last, __c, __len1, __len2,
4685                                            __buf.first, __buf.second);
4686#else  // _LIBCPP_DEBUG
4687    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4688    return _VSTD::__inplace_merge<_Comp_ref>(__first, __middle, __last, __comp, __len1, __len2,
4689                                            __buf.first, __buf.second);
4690#endif  // _LIBCPP_DEBUG
4691}
4692
4693template <class _BidirectionalIterator>
4694inline _LIBCPP_INLINE_VISIBILITY
4695void
4696inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last)
4697{
4698    _VSTD::inplace_merge(__first, __middle, __last,
4699                        __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
4700}
4701
4702// stable_sort
4703
4704template <class _Compare, class _InputIterator1, class _InputIterator2>
4705void
4706__merge_move_construct(_InputIterator1 __first1, _InputIterator1 __last1,
4707        _InputIterator2 __first2, _InputIterator2 __last2,
4708        typename iterator_traits<_InputIterator1>::value_type* __result, _Compare __comp)
4709{
4710    typedef typename iterator_traits<_InputIterator1>::value_type value_type;
4711    __destruct_n __d(0);
4712    unique_ptr<value_type, __destruct_n&> __h(__result, __d);
4713    for (; true; ++__result)
4714    {
4715        if (__first1 == __last1)
4716        {
4717            for (; __first2 != __last2; ++__first2, ++__result, __d.__incr((value_type*)0))
4718                ::new (__result) value_type(_VSTD::move(*__first2));
4719            __h.release();
4720            return;
4721        }
4722        if (__first2 == __last2)
4723        {
4724            for (; __first1 != __last1; ++__first1, ++__result, __d.__incr((value_type*)0))
4725                ::new (__result) value_type(_VSTD::move(*__first1));
4726            __h.release();
4727            return;
4728        }
4729        if (__comp(*__first2, *__first1))
4730        {
4731            ::new (__result) value_type(_VSTD::move(*__first2));
4732            __d.__incr((value_type*)0);
4733            ++__first2;
4734        }
4735        else
4736        {
4737            ::new (__result) value_type(_VSTD::move(*__first1));
4738            __d.__incr((value_type*)0);
4739            ++__first1;
4740        }
4741    }
4742}
4743
4744template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
4745void
4746__merge_move_assign(_InputIterator1 __first1, _InputIterator1 __last1,
4747        _InputIterator2 __first2, _InputIterator2 __last2,
4748        _OutputIterator __result, _Compare __comp)
4749{
4750    for (; __first1 != __last1; ++__result)
4751    {
4752        if (__first2 == __last2)
4753        {
4754            for (; __first1 != __last1; ++__first1, ++__result)
4755                *__result = _VSTD::move(*__first1);
4756            return;
4757        }
4758        if (__comp(*__first2, *__first1))
4759        {
4760            *__result = _VSTD::move(*__first2);
4761            ++__first2;
4762        }
4763        else
4764        {
4765            *__result = _VSTD::move(*__first1);
4766            ++__first1;
4767        }
4768    }
4769    for (; __first2 != __last2; ++__first2, ++__result)
4770        *__result = _VSTD::move(*__first2);
4771}
4772
4773template <class _Compare, class _RandomAccessIterator>
4774void
4775__stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4776              typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4777              typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size);
4778
4779template <class _Compare, class _RandomAccessIterator>
4780void
4781__stable_sort_move(_RandomAccessIterator __first1, _RandomAccessIterator __last1, _Compare __comp,
4782                   typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4783                   typename iterator_traits<_RandomAccessIterator>::value_type* __first2)
4784{
4785    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4786    switch (__len)
4787    {
4788    case 0:
4789        return;
4790    case 1:
4791        ::new(__first2) value_type(_VSTD::move(*__first1));
4792        return;
4793    case 2:
4794       __destruct_n __d(0);
4795        unique_ptr<value_type, __destruct_n&> __h2(__first2, __d);
4796         if (__comp(*--__last1, *__first1))
4797        {
4798            ::new(__first2) value_type(_VSTD::move(*__last1));
4799            __d.__incr((value_type*)0);
4800            ++__first2;
4801            ::new(__first2) value_type(_VSTD::move(*__first1));
4802        }
4803        else
4804        {
4805            ::new(__first2) value_type(_VSTD::move(*__first1));
4806            __d.__incr((value_type*)0);
4807            ++__first2;
4808            ::new(__first2) value_type(_VSTD::move(*__last1));
4809        }
4810        __h2.release();
4811        return;
4812    }
4813    if (__len <= 8)
4814    {
4815        __insertion_sort_move<_Compare>(__first1, __last1, __first2, __comp);
4816        return;
4817    }
4818    typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
4819    _RandomAccessIterator __m = __first1 + __l2;
4820    __stable_sort<_Compare>(__first1, __m, __comp, __l2, __first2, __l2);
4821    __stable_sort<_Compare>(__m, __last1, __comp, __len - __l2, __first2 + __l2, __len - __l2);
4822    __merge_move_construct<_Compare>(__first1, __m, __m, __last1, __first2, __comp);
4823}
4824
4825template <class _Tp>
4826struct __stable_sort_switch
4827{
4828    static const unsigned value = 128*is_trivially_copy_assignable<_Tp>::value;
4829};
4830
4831template <class _Compare, class _RandomAccessIterator>
4832void
4833__stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4834              typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4835              typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size)
4836{
4837    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4838    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4839    switch (__len)
4840    {
4841    case 0:
4842    case 1:
4843        return;
4844    case 2:
4845        if (__comp(*--__last, *__first))
4846            swap(*__first, *__last);
4847        return;
4848    }
4849    if (__len <= static_cast<difference_type>(__stable_sort_switch<value_type>::value))
4850    {
4851        __insertion_sort<_Compare>(__first, __last, __comp);
4852        return;
4853    }
4854    typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
4855    _RandomAccessIterator __m = __first + __l2;
4856    if (__len <= __buff_size)
4857    {
4858        __destruct_n __d(0);
4859        unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
4860        __stable_sort_move<_Compare>(__first, __m, __comp, __l2, __buff);
4861        __d.__set(__l2, (value_type*)0);
4862        __stable_sort_move<_Compare>(__m, __last, __comp, __len - __l2, __buff + __l2);
4863        __d.__set(__len, (value_type*)0);
4864        __merge_move_assign<_Compare>(__buff, __buff + __l2, __buff + __l2, __buff + __len, __first, __comp);
4865//         __merge<_Compare>(move_iterator<value_type*>(__buff),
4866//                           move_iterator<value_type*>(__buff + __l2),
4867//                           move_iterator<_RandomAccessIterator>(__buff + __l2),
4868//                           move_iterator<_RandomAccessIterator>(__buff + __len),
4869//                           __first, __comp);
4870        return;
4871    }
4872    __stable_sort<_Compare>(__first, __m, __comp, __l2, __buff, __buff_size);
4873    __stable_sort<_Compare>(__m, __last, __comp, __len - __l2, __buff, __buff_size);
4874    __inplace_merge<_Compare>(__first, __m, __last, __comp, __l2, __len - __l2, __buff, __buff_size);
4875}
4876
4877template <class _RandomAccessIterator, class _Compare>
4878inline _LIBCPP_INLINE_VISIBILITY
4879void
4880stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4881{
4882    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4883    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4884    difference_type __len = __last - __first;
4885    pair<value_type*, ptrdiff_t> __buf(0, 0);
4886    unique_ptr<value_type, __return_temporary_buffer> __h;
4887    if (__len > static_cast<difference_type>(__stable_sort_switch<value_type>::value))
4888    {
4889        __buf = _VSTD::get_temporary_buffer<value_type>(__len);
4890        __h.reset(__buf.first);
4891    }
4892#ifdef _LIBCPP_DEBUG
4893    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4894    __debug_less<_Compare> __c(__comp);
4895    __stable_sort<_Comp_ref>(__first, __last, __c, __len, __buf.first, __buf.second);
4896#else  // _LIBCPP_DEBUG
4897    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4898    __stable_sort<_Comp_ref>(__first, __last, __comp, __len, __buf.first, __buf.second);
4899#endif  // _LIBCPP_DEBUG
4900}
4901
4902template <class _RandomAccessIterator>
4903inline _LIBCPP_INLINE_VISIBILITY
4904void
4905stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
4906{
4907    _VSTD::stable_sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4908}
4909
4910// is_heap_until
4911
4912template <class _RandomAccessIterator, class _Compare>
4913_RandomAccessIterator
4914is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4915{
4916    typedef typename _VSTD::iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4917    difference_type __len = __last - __first;
4918    difference_type __p = 0;
4919    difference_type __c = 1;
4920    _RandomAccessIterator __pp = __first;
4921    while (__c < __len)
4922    {
4923        _RandomAccessIterator __cp = __first + __c;
4924        if (__comp(*__pp, *__cp))
4925            return __cp;
4926        ++__c;
4927        ++__cp;
4928        if (__c == __len)
4929            return __last;
4930        if (__comp(*__pp, *__cp))
4931            return __cp;
4932        ++__p;
4933        ++__pp;
4934        __c = 2 * __p + 1;
4935    }
4936    return __last;
4937}
4938
4939template<class _RandomAccessIterator>
4940inline _LIBCPP_INLINE_VISIBILITY
4941_RandomAccessIterator
4942is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last)
4943{
4944    return _VSTD::is_heap_until(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4945}
4946
4947// is_heap
4948
4949template <class _RandomAccessIterator, class _Compare>
4950inline _LIBCPP_INLINE_VISIBILITY
4951bool
4952is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4953{
4954    return _VSTD::is_heap_until(__first, __last, __comp) == __last;
4955}
4956
4957template<class _RandomAccessIterator>
4958inline _LIBCPP_INLINE_VISIBILITY
4959bool
4960is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
4961{
4962    return _VSTD::is_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4963}
4964
4965// push_heap
4966
4967template <class _Compare, class _RandomAccessIterator>
4968void
4969__sift_up(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4970          typename iterator_traits<_RandomAccessIterator>::difference_type __len)
4971{
4972    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4973    if (__len > 1)
4974    {
4975        __len = (__len - 2) / 2;
4976        _RandomAccessIterator __ptr = __first + __len;
4977        if (__comp(*__ptr, *--__last))
4978        {
4979            value_type __t(_VSTD::move(*__last));
4980            do
4981            {
4982                *__last = _VSTD::move(*__ptr);
4983                __last = __ptr;
4984                if (__len == 0)
4985                    break;
4986                __len = (__len - 1) / 2;
4987                __ptr = __first + __len;
4988            } while (__comp(*__ptr, __t));
4989            *__last = _VSTD::move(__t);
4990        }
4991    }
4992}
4993
4994template <class _RandomAccessIterator, class _Compare>
4995inline _LIBCPP_INLINE_VISIBILITY
4996void
4997push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4998{
4999#ifdef _LIBCPP_DEBUG
5000    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5001    __debug_less<_Compare> __c(__comp);
5002    __sift_up<_Comp_ref>(__first, __last, __c, __last - __first);
5003#else  // _LIBCPP_DEBUG
5004    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5005    __sift_up<_Comp_ref>(__first, __last, __comp, __last - __first);
5006#endif  // _LIBCPP_DEBUG
5007}
5008
5009template <class _RandomAccessIterator>
5010inline _LIBCPP_INLINE_VISIBILITY
5011void
5012push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
5013{
5014    _VSTD::push_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5015}
5016
5017// pop_heap
5018
5019template <class _Compare, class _RandomAccessIterator>
5020void
5021__sift_down(_RandomAccessIterator __first, _RandomAccessIterator /*__last*/,
5022            _Compare __comp,
5023            typename iterator_traits<_RandomAccessIterator>::difference_type __len,
5024            _RandomAccessIterator __start)
5025{
5026    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
5027    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
5028    // left-child of __start is at 2 * __start + 1
5029    // right-child of __start is at 2 * __start + 2
5030    difference_type __child = __start - __first;
5031
5032    if (__len < 2 || (__len - 2) / 2 < __child)
5033        return;
5034
5035    __child = 2 * __child + 1;
5036    _RandomAccessIterator __child_i = __first + __child;
5037
5038    if ((__child + 1) < __len && __comp(*__child_i, *(__child_i + 1))) {
5039        // right-child exists and is greater than left-child
5040        ++__child_i;
5041        ++__child;
5042    }
5043
5044    // check if we are in heap-order
5045    if (__comp(*__child_i, *__start))
5046        // we are, __start is larger than it's largest child
5047        return;
5048
5049    value_type __top(_VSTD::move(*__start));
5050    do
5051    {
5052        // we are not in heap-order, swap the parent with it's largest child
5053        *__start = _VSTD::move(*__child_i);
5054        __start = __child_i;
5055
5056        if ((__len - 2) / 2 < __child)
5057            break;
5058
5059        // recompute the child based off of the updated parent
5060        __child = 2 * __child + 1;
5061        __child_i = __first + __child;
5062
5063        if ((__child + 1) < __len && __comp(*__child_i, *(__child_i + 1))) {
5064            // right-child exists and is greater than left-child
5065            ++__child_i;
5066            ++__child;
5067        }
5068
5069        // check if we are in heap-order
5070    } while (!__comp(*__child_i, __top));
5071    *__start = _VSTD::move(__top);
5072}
5073
5074template <class _Compare, class _RandomAccessIterator>
5075inline _LIBCPP_INLINE_VISIBILITY
5076void
5077__pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
5078           typename iterator_traits<_RandomAccessIterator>::difference_type __len)
5079{
5080    if (__len > 1)
5081    {
5082        swap(*__first, *--__last);
5083        __sift_down<_Compare>(__first, __last, __comp, __len - 1, __first);
5084    }
5085}
5086
5087template <class _RandomAccessIterator, class _Compare>
5088inline _LIBCPP_INLINE_VISIBILITY
5089void
5090pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
5091{
5092#ifdef _LIBCPP_DEBUG
5093    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5094    __debug_less<_Compare> __c(__comp);
5095    __pop_heap<_Comp_ref>(__first, __last, __c, __last - __first);
5096#else  // _LIBCPP_DEBUG
5097    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5098    __pop_heap<_Comp_ref>(__first, __last, __comp, __last - __first);
5099#endif  // _LIBCPP_DEBUG
5100}
5101
5102template <class _RandomAccessIterator>
5103inline _LIBCPP_INLINE_VISIBILITY
5104void
5105pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
5106{
5107    _VSTD::pop_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5108}
5109
5110// make_heap
5111
5112template <class _Compare, class _RandomAccessIterator>
5113void
5114__make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
5115{
5116    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
5117    difference_type __n = __last - __first;
5118    if (__n > 1)
5119    {
5120        // start from the first parent, there is no need to consider children
5121        for (difference_type __start = (__n - 2) / 2; __start >= 0; --__start)
5122        {
5123            __sift_down<_Compare>(__first, __last, __comp, __n, __first + __start);
5124        }
5125    }
5126}
5127
5128template <class _RandomAccessIterator, class _Compare>
5129inline _LIBCPP_INLINE_VISIBILITY
5130void
5131make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
5132{
5133#ifdef _LIBCPP_DEBUG
5134    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5135    __debug_less<_Compare> __c(__comp);
5136    __make_heap<_Comp_ref>(__first, __last, __c);
5137#else  // _LIBCPP_DEBUG
5138    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5139    __make_heap<_Comp_ref>(__first, __last, __comp);
5140#endif  // _LIBCPP_DEBUG
5141}
5142
5143template <class _RandomAccessIterator>
5144inline _LIBCPP_INLINE_VISIBILITY
5145void
5146make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
5147{
5148    _VSTD::make_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5149}
5150
5151// sort_heap
5152
5153template <class _Compare, class _RandomAccessIterator>
5154void
5155__sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
5156{
5157    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
5158    for (difference_type __n = __last - __first; __n > 1; --__last, --__n)
5159        __pop_heap<_Compare>(__first, __last, __comp, __n);
5160}
5161
5162template <class _RandomAccessIterator, class _Compare>
5163inline _LIBCPP_INLINE_VISIBILITY
5164void
5165sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
5166{
5167#ifdef _LIBCPP_DEBUG
5168    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5169    __debug_less<_Compare> __c(__comp);
5170    __sort_heap<_Comp_ref>(__first, __last, __c);
5171#else  // _LIBCPP_DEBUG
5172    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5173    __sort_heap<_Comp_ref>(__first, __last, __comp);
5174#endif  // _LIBCPP_DEBUG
5175}
5176
5177template <class _RandomAccessIterator>
5178inline _LIBCPP_INLINE_VISIBILITY
5179void
5180sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
5181{
5182    _VSTD::sort_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5183}
5184
5185// partial_sort
5186
5187template <class _Compare, class _RandomAccessIterator>
5188void
5189__partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
5190             _Compare __comp)
5191{
5192    __make_heap<_Compare>(__first, __middle, __comp);
5193    typename iterator_traits<_RandomAccessIterator>::difference_type __len = __middle - __first;
5194    for (_RandomAccessIterator __i = __middle; __i != __last; ++__i)
5195    {
5196        if (__comp(*__i, *__first))
5197        {
5198            swap(*__i, *__first);
5199            __sift_down<_Compare>(__first, __middle, __comp, __len, __first);
5200        }
5201    }
5202    __sort_heap<_Compare>(__first, __middle, __comp);
5203}
5204
5205template <class _RandomAccessIterator, class _Compare>
5206inline _LIBCPP_INLINE_VISIBILITY
5207void
5208partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
5209             _Compare __comp)
5210{
5211#ifdef _LIBCPP_DEBUG
5212    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5213    __debug_less<_Compare> __c(__comp);
5214    __partial_sort<_Comp_ref>(__first, __middle, __last, __c);
5215#else  // _LIBCPP_DEBUG
5216    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5217    __partial_sort<_Comp_ref>(__first, __middle, __last, __comp);
5218#endif  // _LIBCPP_DEBUG
5219}
5220
5221template <class _RandomAccessIterator>
5222inline _LIBCPP_INLINE_VISIBILITY
5223void
5224partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)
5225{
5226    _VSTD::partial_sort(__first, __middle, __last,
5227                       __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5228}
5229
5230// partial_sort_copy
5231
5232template <class _Compare, class _InputIterator, class _RandomAccessIterator>
5233_RandomAccessIterator
5234__partial_sort_copy(_InputIterator __first, _InputIterator __last,
5235                    _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
5236{
5237    _RandomAccessIterator __r = __result_first;
5238    if (__r != __result_last)
5239    {
5240        for (; __first != __last && __r != __result_last; (void) ++__first, ++__r)
5241            *__r = *__first;
5242        __make_heap<_Compare>(__result_first, __r, __comp);
5243        typename iterator_traits<_RandomAccessIterator>::difference_type __len = __r - __result_first;
5244        for (; __first != __last; ++__first)
5245            if (__comp(*__first, *__result_first))
5246            {
5247                *__result_first = *__first;
5248                __sift_down<_Compare>(__result_first, __r, __comp, __len, __result_first);
5249            }
5250        __sort_heap<_Compare>(__result_first, __r, __comp);
5251    }
5252    return __r;
5253}
5254
5255template <class _InputIterator, class _RandomAccessIterator, class _Compare>
5256inline _LIBCPP_INLINE_VISIBILITY
5257_RandomAccessIterator
5258partial_sort_copy(_InputIterator __first, _InputIterator __last,
5259                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
5260{
5261#ifdef _LIBCPP_DEBUG
5262    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5263    __debug_less<_Compare> __c(__comp);
5264    return __partial_sort_copy<_Comp_ref>(__first, __last, __result_first, __result_last, __c);
5265#else  // _LIBCPP_DEBUG
5266    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5267    return __partial_sort_copy<_Comp_ref>(__first, __last, __result_first, __result_last, __comp);
5268#endif  // _LIBCPP_DEBUG
5269}
5270
5271template <class _InputIterator, class _RandomAccessIterator>
5272inline _LIBCPP_INLINE_VISIBILITY
5273_RandomAccessIterator
5274partial_sort_copy(_InputIterator __first, _InputIterator __last,
5275                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last)
5276{
5277    return _VSTD::partial_sort_copy(__first, __last, __result_first, __result_last,
5278                                   __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5279}
5280
5281// nth_element
5282
5283template <class _Compare, class _RandomAccessIterator>
5284void
5285__nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp)
5286{
5287    // _Compare is known to be a reference type
5288    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
5289    const difference_type __limit = 7;
5290    while (true)
5291    {
5292    __restart:
5293        if (__nth == __last)
5294            return;
5295        difference_type __len = __last - __first;
5296        switch (__len)
5297        {
5298        case 0:
5299        case 1:
5300            return;
5301        case 2:
5302            if (__comp(*--__last, *__first))
5303                swap(*__first, *__last);
5304            return;
5305        case 3:
5306            {
5307            _RandomAccessIterator __m = __first;
5308            _VSTD::__sort3<_Compare>(__first, ++__m, --__last, __comp);
5309            return;
5310            }
5311        }
5312        if (__len <= __limit)
5313        {
5314            __selection_sort<_Compare>(__first, __last, __comp);
5315            return;
5316        }
5317        // __len > __limit >= 3
5318        _RandomAccessIterator __m = __first + __len/2;
5319        _RandomAccessIterator __lm1 = __last;
5320        unsigned __n_swaps = _VSTD::__sort3<_Compare>(__first, __m, --__lm1, __comp);
5321        // *__m is median
5322        // partition [__first, __m) < *__m and *__m <= [__m, __last)
5323        // (this inhibits tossing elements equivalent to __m around unnecessarily)
5324        _RandomAccessIterator __i = __first;
5325        _RandomAccessIterator __j = __lm1;
5326        // j points beyond range to be tested, *__lm1 is known to be <= *__m
5327        // The search going up is known to be guarded but the search coming down isn't.
5328        // Prime the downward search with a guard.
5329        if (!__comp(*__i, *__m))  // if *__first == *__m
5330        {
5331            // *__first == *__m, *__first doesn't go in first part
5332            // manually guard downward moving __j against __i
5333            while (true)
5334            {
5335                if (__i == --__j)
5336                {
5337                    // *__first == *__m, *__m <= all other elements
5338                    // Parition instead into [__first, __i) == *__first and *__first < [__i, __last)
5339                    ++__i;  // __first + 1
5340                    __j = __last;
5341                    if (!__comp(*__first, *--__j))  // we need a guard if *__first == *(__last-1)
5342                    {
5343                        while (true)
5344                        {
5345                            if (__i == __j)
5346                                return;  // [__first, __last) all equivalent elements
5347                            if (__comp(*__first, *__i))
5348                            {
5349                                swap(*__i, *__j);
5350                                ++__n_swaps;
5351                                ++__i;
5352                                break;
5353                            }
5354                            ++__i;
5355                        }
5356                    }
5357                    // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
5358                    if (__i == __j)
5359                        return;
5360                    while (true)
5361                    {
5362                        while (!__comp(*__first, *__i))
5363                            ++__i;
5364                        while (__comp(*__first, *--__j))
5365                            ;
5366                        if (__i >= __j)
5367                            break;
5368                        swap(*__i, *__j);
5369                        ++__n_swaps;
5370                        ++__i;
5371                    }
5372                    // [__first, __i) == *__first and *__first < [__i, __last)
5373                    // The first part is sorted,
5374                    if (__nth < __i)
5375                        return;
5376                    // __nth_element the secod part
5377                    // __nth_element<_Compare>(__i, __nth, __last, __comp);
5378                    __first = __i;
5379                    goto __restart;
5380                }
5381                if (__comp(*__j, *__m))
5382                {
5383                    swap(*__i, *__j);
5384                    ++__n_swaps;
5385                    break;  // found guard for downward moving __j, now use unguarded partition
5386                }
5387            }
5388        }
5389        ++__i;
5390        // j points beyond range to be tested, *__lm1 is known to be <= *__m
5391        // if not yet partitioned...
5392        if (__i < __j)
5393        {
5394            // known that *(__i - 1) < *__m
5395            while (true)
5396            {
5397                // __m still guards upward moving __i
5398                while (__comp(*__i, *__m))
5399                    ++__i;
5400                // It is now known that a guard exists for downward moving __j
5401                while (!__comp(*--__j, *__m))
5402                    ;
5403                if (__i >= __j)
5404                    break;
5405                swap(*__i, *__j);
5406                ++__n_swaps;
5407                // It is known that __m != __j
5408                // If __m just moved, follow it
5409                if (__m == __i)
5410                    __m = __j;
5411                ++__i;
5412            }
5413        }
5414        // [__first, __i) < *__m and *__m <= [__i, __last)
5415        if (__i != __m && __comp(*__m, *__i))
5416        {
5417            swap(*__i, *__m);
5418            ++__n_swaps;
5419        }
5420        // [__first, __i) < *__i and *__i <= [__i+1, __last)
5421        if (__nth == __i)
5422            return;
5423        if (__n_swaps == 0)
5424        {
5425            // We were given a perfectly partitioned sequence.  Coincidence?
5426            if (__nth < __i)
5427            {
5428                // Check for [__first, __i) already sorted
5429                __j = __m = __first;
5430                while (++__j != __i)
5431                {
5432                    if (__comp(*__j, *__m))
5433                        // not yet sorted, so sort
5434                        goto not_sorted;
5435                    __m = __j;
5436                }
5437                // [__first, __i) sorted
5438                return;
5439            }
5440            else
5441            {
5442                // Check for [__i, __last) already sorted
5443                __j = __m = __i;
5444                while (++__j != __last)
5445                {
5446                    if (__comp(*__j, *__m))
5447                        // not yet sorted, so sort
5448                        goto not_sorted;
5449                    __m = __j;
5450                }
5451                // [__i, __last) sorted
5452                return;
5453            }
5454        }
5455not_sorted:
5456        // __nth_element on range containing __nth
5457        if (__nth < __i)
5458        {
5459            // __nth_element<_Compare>(__first, __nth, __i, __comp);
5460            __last = __i;
5461        }
5462        else
5463        {
5464            // __nth_element<_Compare>(__i+1, __nth, __last, __comp);
5465            __first = ++__i;
5466        }
5467    }
5468}
5469
5470template <class _RandomAccessIterator, class _Compare>
5471inline _LIBCPP_INLINE_VISIBILITY
5472void
5473nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp)
5474{
5475#ifdef _LIBCPP_DEBUG
5476    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5477    __debug_less<_Compare> __c(__comp);
5478    __nth_element<_Comp_ref>(__first, __nth, __last, __c);
5479#else  // _LIBCPP_DEBUG
5480    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5481    __nth_element<_Comp_ref>(__first, __nth, __last, __comp);
5482#endif  // _LIBCPP_DEBUG
5483}
5484
5485template <class _RandomAccessIterator>
5486inline _LIBCPP_INLINE_VISIBILITY
5487void
5488nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last)
5489{
5490    _VSTD::nth_element(__first, __nth, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5491}
5492
5493// includes
5494
5495template <class _Compare, class _InputIterator1, class _InputIterator2>
5496bool
5497__includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
5498           _Compare __comp)
5499{
5500    for (; __first2 != __last2; ++__first1)
5501    {
5502        if (__first1 == __last1 || __comp(*__first2, *__first1))
5503            return false;
5504        if (!__comp(*__first1, *__first2))
5505            ++__first2;
5506    }
5507    return true;
5508}
5509
5510template <class _InputIterator1, class _InputIterator2, class _Compare>
5511inline _LIBCPP_INLINE_VISIBILITY
5512bool
5513includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
5514         _Compare __comp)
5515{
5516#ifdef _LIBCPP_DEBUG
5517    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5518    __debug_less<_Compare> __c(__comp);
5519    return __includes<_Comp_ref>(__first1, __last1, __first2, __last2, __c);
5520#else  // _LIBCPP_DEBUG
5521    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5522    return __includes<_Comp_ref>(__first1, __last1, __first2, __last2, __comp);
5523#endif  // _LIBCPP_DEBUG
5524}
5525
5526template <class _InputIterator1, class _InputIterator2>
5527inline _LIBCPP_INLINE_VISIBILITY
5528bool
5529includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2)
5530{
5531    return _VSTD::includes(__first1, __last1, __first2, __last2,
5532                          __less<typename iterator_traits<_InputIterator1>::value_type,
5533                                 typename iterator_traits<_InputIterator2>::value_type>());
5534}
5535
5536// set_union
5537
5538template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5539_OutputIterator
5540__set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5541            _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5542{
5543    for (; __first1 != __last1; ++__result)
5544    {
5545        if (__first2 == __last2)
5546            return _VSTD::copy(__first1, __last1, __result);
5547        if (__comp(*__first2, *__first1))
5548        {
5549            *__result = *__first2;
5550            ++__first2;
5551        }
5552        else
5553        {
5554            *__result = *__first1;
5555            if (!__comp(*__first1, *__first2))
5556                ++__first2;
5557            ++__first1;
5558        }
5559    }
5560    return _VSTD::copy(__first2, __last2, __result);
5561}
5562
5563template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5564inline _LIBCPP_INLINE_VISIBILITY
5565_OutputIterator
5566set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5567          _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5568{
5569#ifdef _LIBCPP_DEBUG
5570    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5571    __debug_less<_Compare> __c(__comp);
5572    return __set_union<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5573#else  // _LIBCPP_DEBUG
5574    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5575    return __set_union<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5576#endif  // _LIBCPP_DEBUG
5577}
5578
5579template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5580inline _LIBCPP_INLINE_VISIBILITY
5581_OutputIterator
5582set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5583          _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5584{
5585    return _VSTD::set_union(__first1, __last1, __first2, __last2, __result,
5586                          __less<typename iterator_traits<_InputIterator1>::value_type,
5587                                 typename iterator_traits<_InputIterator2>::value_type>());
5588}
5589
5590// set_intersection
5591
5592template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5593_OutputIterator
5594__set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5595                   _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5596{
5597    while (__first1 != __last1 && __first2 != __last2)
5598    {
5599        if (__comp(*__first1, *__first2))
5600            ++__first1;
5601        else
5602        {
5603            if (!__comp(*__first2, *__first1))
5604            {
5605                *__result = *__first1;
5606                ++__result;
5607                ++__first1;
5608            }
5609            ++__first2;
5610        }
5611    }
5612    return __result;
5613}
5614
5615template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5616inline _LIBCPP_INLINE_VISIBILITY
5617_OutputIterator
5618set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5619                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5620{
5621#ifdef _LIBCPP_DEBUG
5622    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5623    __debug_less<_Compare> __c(__comp);
5624    return __set_intersection<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5625#else  // _LIBCPP_DEBUG
5626    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5627    return __set_intersection<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5628#endif  // _LIBCPP_DEBUG
5629}
5630
5631template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5632inline _LIBCPP_INLINE_VISIBILITY
5633_OutputIterator
5634set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5635                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5636{
5637    return _VSTD::set_intersection(__first1, __last1, __first2, __last2, __result,
5638                                  __less<typename iterator_traits<_InputIterator1>::value_type,
5639                                         typename iterator_traits<_InputIterator2>::value_type>());
5640}
5641
5642// set_difference
5643
5644template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5645_OutputIterator
5646__set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5647                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5648{
5649    while (__first1 != __last1)
5650    {
5651        if (__first2 == __last2)
5652            return _VSTD::copy(__first1, __last1, __result);
5653        if (__comp(*__first1, *__first2))
5654        {
5655            *__result = *__first1;
5656            ++__result;
5657            ++__first1;
5658        }
5659        else
5660        {
5661            if (!__comp(*__first2, *__first1))
5662                ++__first1;
5663            ++__first2;
5664        }
5665    }
5666    return __result;
5667}
5668
5669template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5670inline _LIBCPP_INLINE_VISIBILITY
5671_OutputIterator
5672set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5673               _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5674{
5675#ifdef _LIBCPP_DEBUG
5676    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5677    __debug_less<_Compare> __c(__comp);
5678    return __set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5679#else  // _LIBCPP_DEBUG
5680    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5681    return __set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5682#endif  // _LIBCPP_DEBUG
5683}
5684
5685template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5686inline _LIBCPP_INLINE_VISIBILITY
5687_OutputIterator
5688set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5689               _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5690{
5691    return _VSTD::set_difference(__first1, __last1, __first2, __last2, __result,
5692                                __less<typename iterator_traits<_InputIterator1>::value_type,
5693                                       typename iterator_traits<_InputIterator2>::value_type>());
5694}
5695
5696// set_symmetric_difference
5697
5698template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5699_OutputIterator
5700__set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5701                           _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5702{
5703    while (__first1 != __last1)
5704    {
5705        if (__first2 == __last2)
5706            return _VSTD::copy(__first1, __last1, __result);
5707        if (__comp(*__first1, *__first2))
5708        {
5709            *__result = *__first1;
5710            ++__result;
5711            ++__first1;
5712        }
5713        else
5714        {
5715            if (__comp(*__first2, *__first1))
5716            {
5717                *__result = *__first2;
5718                ++__result;
5719            }
5720            else
5721                ++__first1;
5722            ++__first2;
5723        }
5724    }
5725    return _VSTD::copy(__first2, __last2, __result);
5726}
5727
5728template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5729inline _LIBCPP_INLINE_VISIBILITY
5730_OutputIterator
5731set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5732                         _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5733{
5734#ifdef _LIBCPP_DEBUG
5735    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5736    __debug_less<_Compare> __c(__comp);
5737    return __set_symmetric_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5738#else  // _LIBCPP_DEBUG
5739    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5740    return __set_symmetric_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5741#endif  // _LIBCPP_DEBUG
5742}
5743
5744template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5745inline _LIBCPP_INLINE_VISIBILITY
5746_OutputIterator
5747set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5748                         _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5749{
5750    return _VSTD::set_symmetric_difference(__first1, __last1, __first2, __last2, __result,
5751                                          __less<typename iterator_traits<_InputIterator1>::value_type,
5752                                                 typename iterator_traits<_InputIterator2>::value_type>());
5753}
5754
5755// lexicographical_compare
5756
5757template <class _Compare, class _InputIterator1, class _InputIterator2>
5758bool
5759__lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
5760                          _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
5761{
5762    for (; __first2 != __last2; ++__first1, (void) ++__first2)
5763    {
5764        if (__first1 == __last1 || __comp(*__first1, *__first2))
5765            return true;
5766        if (__comp(*__first2, *__first1))
5767            return false;
5768    }
5769    return false;
5770}
5771
5772template <class _InputIterator1, class _InputIterator2, class _Compare>
5773inline _LIBCPP_INLINE_VISIBILITY
5774bool
5775lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
5776                        _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
5777{
5778#ifdef _LIBCPP_DEBUG
5779    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5780    __debug_less<_Compare> __c(__comp);
5781    return __lexicographical_compare<_Comp_ref>(__first1, __last1, __first2, __last2, __c);
5782#else  // _LIBCPP_DEBUG
5783    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5784    return __lexicographical_compare<_Comp_ref>(__first1, __last1, __first2, __last2, __comp);
5785#endif  // _LIBCPP_DEBUG
5786}
5787
5788template <class _InputIterator1, class _InputIterator2>
5789inline _LIBCPP_INLINE_VISIBILITY
5790bool
5791lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
5792                        _InputIterator2 __first2, _InputIterator2 __last2)
5793{
5794    return _VSTD::lexicographical_compare(__first1, __last1, __first2, __last2,
5795                                         __less<typename iterator_traits<_InputIterator1>::value_type,
5796                                                typename iterator_traits<_InputIterator2>::value_type>());
5797}
5798
5799// next_permutation
5800
5801template <class _Compare, class _BidirectionalIterator>
5802bool
5803__next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5804{
5805    _BidirectionalIterator __i = __last;
5806    if (__first == __last || __first == --__i)
5807        return false;
5808    while (true)
5809    {
5810        _BidirectionalIterator __ip1 = __i;
5811        if (__comp(*--__i, *__ip1))
5812        {
5813            _BidirectionalIterator __j = __last;
5814            while (!__comp(*__i, *--__j))
5815                ;
5816            swap(*__i, *__j);
5817            _VSTD::reverse(__ip1, __last);
5818            return true;
5819        }
5820        if (__i == __first)
5821        {
5822            _VSTD::reverse(__first, __last);
5823            return false;
5824        }
5825    }
5826}
5827
5828template <class _BidirectionalIterator, class _Compare>
5829inline _LIBCPP_INLINE_VISIBILITY
5830bool
5831next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5832{
5833#ifdef _LIBCPP_DEBUG
5834    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5835    __debug_less<_Compare> __c(__comp);
5836    return __next_permutation<_Comp_ref>(__first, __last, __c);
5837#else  // _LIBCPP_DEBUG
5838    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5839    return __next_permutation<_Comp_ref>(__first, __last, __comp);
5840#endif  // _LIBCPP_DEBUG
5841}
5842
5843template <class _BidirectionalIterator>
5844inline _LIBCPP_INLINE_VISIBILITY
5845bool
5846next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
5847{
5848    return _VSTD::next_permutation(__first, __last,
5849                                  __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
5850}
5851
5852// prev_permutation
5853
5854template <class _Compare, class _BidirectionalIterator>
5855bool
5856__prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5857{
5858    _BidirectionalIterator __i = __last;
5859    if (__first == __last || __first == --__i)
5860        return false;
5861    while (true)
5862    {
5863        _BidirectionalIterator __ip1 = __i;
5864        if (__comp(*__ip1, *--__i))
5865        {
5866            _BidirectionalIterator __j = __last;
5867            while (!__comp(*--__j, *__i))
5868                ;
5869            swap(*__i, *__j);
5870            _VSTD::reverse(__ip1, __last);
5871            return true;
5872        }
5873        if (__i == __first)
5874        {
5875            _VSTD::reverse(__first, __last);
5876            return false;
5877        }
5878    }
5879}
5880
5881template <class _BidirectionalIterator, class _Compare>
5882inline _LIBCPP_INLINE_VISIBILITY
5883bool
5884prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5885{
5886#ifdef _LIBCPP_DEBUG
5887    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5888    __debug_less<_Compare> __c(__comp);
5889    return __prev_permutation<_Comp_ref>(__first, __last, __c);
5890#else  // _LIBCPP_DEBUG
5891    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5892    return __prev_permutation<_Comp_ref>(__first, __last, __comp);
5893#endif  // _LIBCPP_DEBUG
5894}
5895
5896template <class _BidirectionalIterator>
5897inline _LIBCPP_INLINE_VISIBILITY
5898bool
5899prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
5900{
5901    return _VSTD::prev_permutation(__first, __last,
5902                                  __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
5903}
5904
5905_LIBCPP_END_NAMESPACE_STD
5906
5907#endif  // _LIBCPP_ALGORITHM
5908