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 T>
39    InputIterator
40    find(InputIterator first, InputIterator last, const T& value);
41
42template <class InputIterator, class Predicate>
43    InputIterator
44    find_if(InputIterator first, InputIterator last, Predicate pred);
45
46template<class InputIterator, class Predicate>
47    InputIterator
48    find_if_not(InputIterator first, InputIterator last, Predicate pred);
49
50template <class ForwardIterator1, class ForwardIterator2>
51    ForwardIterator1
52    find_end(ForwardIterator1 first1, ForwardIterator1 last1,
53             ForwardIterator2 first2, ForwardIterator2 last2);
54
55template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
56    ForwardIterator1
57    find_end(ForwardIterator1 first1, ForwardIterator1 last1,
58             ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
59
60template <class ForwardIterator1, class ForwardIterator2>
61    ForwardIterator1
62    find_first_of(ForwardIterator1 first1, ForwardIterator1 last1,
63                  ForwardIterator2 first2, ForwardIterator2 last2);
64
65template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
66    ForwardIterator1
67    find_first_of(ForwardIterator1 first1, ForwardIterator1 last1,
68                  ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
69
70template <class ForwardIterator>
71    ForwardIterator
72    adjacent_find(ForwardIterator first, ForwardIterator last);
73
74template <class ForwardIterator, class BinaryPredicate>
75    ForwardIterator
76    adjacent_find(ForwardIterator first, ForwardIterator last, BinaryPredicate pred);
77
78template <class InputIterator, class T>
79    typename iterator_traits<InputIterator>::difference_type
80    count(InputIterator first, InputIterator last, const T& value);
81
82template <class InputIterator, class Predicate>
83    typename iterator_traits<InputIterator>::difference_type
84    count_if(InputIterator first, InputIterator last, Predicate pred);
85
86template <class InputIterator1, class InputIterator2>
87    pair<InputIterator1, InputIterator2>
88    mismatch(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2);
89
90template <class InputIterator1, class InputIterator2>
91    pair<InputIterator1, InputIterator2>
92    mismatch(InputIterator1 first1, InputIterator1 last1,
93             InputIterator2 first2, InputIterator2 last2); // **C++14**
94
95template <class InputIterator1, class InputIterator2, class BinaryPredicate>
96    pair<InputIterator1, InputIterator2>
97    mismatch(InputIterator1 first1, InputIterator1 last1,
98             InputIterator2 first2, BinaryPredicate pred);
99
100template <class InputIterator1, class InputIterator2, class BinaryPredicate>
101    pair<InputIterator1, InputIterator2>
102    mismatch(InputIterator1 first1, InputIterator1 last1,
103             InputIterator2 first2, InputIterator2 last2,
104             BinaryPredicate pred); // **C++14**
105
106template <class InputIterator1, class InputIterator2>
107    bool
108    equal(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2);
109
110template <class InputIterator1, class InputIterator2>
111    bool
112    equal(InputIterator1 first1, InputIterator1 last1,
113          InputIterator2 first2, InputIterator2 last2); // **C++14**
114
115template <class InputIterator1, class InputIterator2, class BinaryPredicate>
116    bool
117    equal(InputIterator1 first1, InputIterator1 last1,
118          InputIterator2 first2, BinaryPredicate pred);
119
120template <class InputIterator1, class InputIterator2, class BinaryPredicate>
121    bool
122    equal(InputIterator1 first1, InputIterator1 last1,
123          InputIterator2 first2, InputIterator2 last2,
124          BinaryPredicate pred); // **C++14**
125
126template<class ForwardIterator1, class ForwardIterator2>
127    bool
128    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
129                   ForwardIterator2 first2);
130
131template<class ForwardIterator1, class ForwardIterator2>
132    bool
133    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
134                   ForwardIterator2 first2, ForwardIterator2 last2); // **C++14**
135
136template<class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
137    bool
138    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
139                   ForwardIterator2 first2, BinaryPredicate pred);
140
141template<class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
142    bool
143    is_permutation(ForwardIterator1 first1, ForwardIterator1 last1,
144                   ForwardIterator2 first2, ForwardIterator2 last2,
145                   BinaryPredicate pred);  // **C++14**
146
147template <class ForwardIterator1, class ForwardIterator2>
148    ForwardIterator1
149    search(ForwardIterator1 first1, ForwardIterator1 last1,
150           ForwardIterator2 first2, ForwardIterator2 last2);
151
152template <class ForwardIterator1, class ForwardIterator2, class BinaryPredicate>
153    ForwardIterator1
154    search(ForwardIterator1 first1, ForwardIterator1 last1,
155           ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);
156
157template <class ForwardIterator, class Size, class T>
158    ForwardIterator
159    search_n(ForwardIterator first, ForwardIterator last, Size count, const T& value);
160
161template <class ForwardIterator, class Size, class T, class BinaryPredicate>
162    ForwardIterator
163    search_n(ForwardIterator first, ForwardIterator last,
164             Size count, const T& value, BinaryPredicate pred);
165
166template <class InputIterator, class OutputIterator>
167    OutputIterator
168    copy(InputIterator first, InputIterator last, OutputIterator result);
169
170template<class InputIterator, class OutputIterator, class Predicate>
171    OutputIterator
172    copy_if(InputIterator first, InputIterator last,
173            OutputIterator result, Predicate pred);
174
175template<class InputIterator, class Size, class OutputIterator>
176    OutputIterator
177    copy_n(InputIterator first, Size n, OutputIterator result);
178
179template <class BidirectionalIterator1, class BidirectionalIterator2>
180    BidirectionalIterator2
181    copy_backward(BidirectionalIterator1 first, BidirectionalIterator1 last,
182                  BidirectionalIterator2 result);
183
184template <class ForwardIterator1, class ForwardIterator2>
185    ForwardIterator2
186    swap_ranges(ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2);
187
188template <class ForwardIterator1, class ForwardIterator2>
189    void
190    iter_swap(ForwardIterator1 a, ForwardIterator2 b);
191
192template <class InputIterator, class OutputIterator, class UnaryOperation>
193    OutputIterator
194    transform(InputIterator first, InputIterator last, OutputIterator result, UnaryOperation op);
195
196template <class InputIterator1, class InputIterator2, class OutputIterator, class BinaryOperation>
197    OutputIterator
198    transform(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2,
199              OutputIterator result, BinaryOperation binary_op);
200
201template <class ForwardIterator, class T>
202    void
203    replace(ForwardIterator first, ForwardIterator last, const T& old_value, const T& new_value);
204
205template <class ForwardIterator, class Predicate, class T>
206    void
207    replace_if(ForwardIterator first, ForwardIterator last, Predicate pred, const T& new_value);
208
209template <class InputIterator, class OutputIterator, class T>
210    OutputIterator
211    replace_copy(InputIterator first, InputIterator last, OutputIterator result,
212                 const T& old_value, const T& new_value);
213
214template <class InputIterator, class OutputIterator, class Predicate, class T>
215    OutputIterator
216    replace_copy_if(InputIterator first, InputIterator last, OutputIterator result, Predicate pred, const T& new_value);
217
218template <class ForwardIterator, class T>
219    void
220    fill(ForwardIterator first, ForwardIterator last, const T& value);
221
222template <class OutputIterator, class Size, class T>
223    OutputIterator
224    fill_n(OutputIterator first, Size n, const T& value);
225
226template <class ForwardIterator, class Generator>
227    void
228    generate(ForwardIterator first, ForwardIterator last, Generator gen);
229
230template <class OutputIterator, class Size, class Generator>
231    OutputIterator
232    generate_n(OutputIterator first, Size n, Generator gen);
233
234template <class ForwardIterator, class T>
235    ForwardIterator
236    remove(ForwardIterator first, ForwardIterator last, const T& value);
237
238template <class ForwardIterator, class Predicate>
239    ForwardIterator
240    remove_if(ForwardIterator first, ForwardIterator last, Predicate pred);
241
242template <class InputIterator, class OutputIterator, class T>
243    OutputIterator
244    remove_copy(InputIterator first, InputIterator last, OutputIterator result, const T& value);
245
246template <class InputIterator, class OutputIterator, class Predicate>
247    OutputIterator
248    remove_copy_if(InputIterator first, InputIterator last, OutputIterator result, Predicate pred);
249
250template <class ForwardIterator>
251    ForwardIterator
252    unique(ForwardIterator first, ForwardIterator last);
253
254template <class ForwardIterator, class BinaryPredicate>
255    ForwardIterator
256    unique(ForwardIterator first, ForwardIterator last, BinaryPredicate pred);
257
258template <class InputIterator, class OutputIterator>
259    OutputIterator
260    unique_copy(InputIterator first, InputIterator last, OutputIterator result);
261
262template <class InputIterator, class OutputIterator, class BinaryPredicate>
263    OutputIterator
264    unique_copy(InputIterator first, InputIterator last, OutputIterator result, BinaryPredicate pred);
265
266template <class BidirectionalIterator>
267    void
268    reverse(BidirectionalIterator first, BidirectionalIterator last);
269
270template <class BidirectionalIterator, class OutputIterator>
271    OutputIterator
272    reverse_copy(BidirectionalIterator first, BidirectionalIterator last, OutputIterator result);
273
274template <class ForwardIterator>
275    ForwardIterator
276    rotate(ForwardIterator first, ForwardIterator middle, ForwardIterator last);
277
278template <class ForwardIterator, class OutputIterator>
279    OutputIterator
280    rotate_copy(ForwardIterator first, ForwardIterator middle, ForwardIterator last, OutputIterator result);
281
282template <class RandomAccessIterator>
283    void
284    random_shuffle(RandomAccessIterator first, RandomAccessIterator last); // deprecated in C++14
285
286template <class RandomAccessIterator, class RandomNumberGenerator>
287    void
288    random_shuffle(RandomAccessIterator first, RandomAccessIterator last,
289                   RandomNumberGenerator& rand);  // deprecated in C++14
290
291template<class RandomAccessIterator, class UniformRandomNumberGenerator>
292    void shuffle(RandomAccessIterator first, RandomAccessIterator last,
293                 UniformRandomNumberGenerator&& g);
294
295template <class InputIterator, class Predicate>
296    bool
297    is_partitioned(InputIterator first, InputIterator last, Predicate pred);
298
299template <class ForwardIterator, class Predicate>
300    ForwardIterator
301    partition(ForwardIterator first, ForwardIterator last, Predicate pred);
302
303template <class InputIterator, class OutputIterator1,
304          class OutputIterator2, class Predicate>
305    pair<OutputIterator1, OutputIterator2>
306    partition_copy(InputIterator first, InputIterator last,
307                   OutputIterator1 out_true, OutputIterator2 out_false,
308                   Predicate pred);
309
310template <class ForwardIterator, class Predicate>
311    ForwardIterator
312    stable_partition(ForwardIterator first, ForwardIterator last, Predicate pred);
313
314template<class ForwardIterator, class Predicate>
315    ForwardIterator
316    partition_point(ForwardIterator first, ForwardIterator last, Predicate pred);
317
318template <class ForwardIterator>
319    bool
320    is_sorted(ForwardIterator first, ForwardIterator last);
321
322template <class ForwardIterator, class Compare>
323    bool
324    is_sorted(ForwardIterator first, ForwardIterator last, Compare comp);
325
326template<class ForwardIterator>
327    ForwardIterator
328    is_sorted_until(ForwardIterator first, ForwardIterator last);
329
330template <class ForwardIterator, class Compare>
331    ForwardIterator
332    is_sorted_until(ForwardIterator first, ForwardIterator last, Compare comp);
333
334template <class RandomAccessIterator>
335    void
336    sort(RandomAccessIterator first, RandomAccessIterator last);
337
338template <class RandomAccessIterator, class Compare>
339    void
340    sort(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
341
342template <class RandomAccessIterator>
343    void
344    stable_sort(RandomAccessIterator first, RandomAccessIterator last);
345
346template <class RandomAccessIterator, class Compare>
347    void
348    stable_sort(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
349
350template <class RandomAccessIterator>
351    void
352    partial_sort(RandomAccessIterator first, RandomAccessIterator middle, RandomAccessIterator last);
353
354template <class RandomAccessIterator, class Compare>
355    void
356    partial_sort(RandomAccessIterator first, RandomAccessIterator middle, RandomAccessIterator last, Compare comp);
357
358template <class InputIterator, class RandomAccessIterator>
359    RandomAccessIterator
360    partial_sort_copy(InputIterator first, InputIterator last,
361                      RandomAccessIterator result_first, RandomAccessIterator result_last);
362
363template <class InputIterator, class RandomAccessIterator, class Compare>
364    RandomAccessIterator
365    partial_sort_copy(InputIterator first, InputIterator last,
366                      RandomAccessIterator result_first, RandomAccessIterator result_last, Compare comp);
367
368template <class RandomAccessIterator>
369    void
370    nth_element(RandomAccessIterator first, RandomAccessIterator nth, RandomAccessIterator last);
371
372template <class RandomAccessIterator, class Compare>
373    void
374    nth_element(RandomAccessIterator first, RandomAccessIterator nth, RandomAccessIterator last, Compare comp);
375
376template <class ForwardIterator, class T>
377    ForwardIterator
378    lower_bound(ForwardIterator first, ForwardIterator last, const T& value);
379
380template <class ForwardIterator, class T, class Compare>
381    ForwardIterator
382    lower_bound(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
383
384template <class ForwardIterator, class T>
385    ForwardIterator
386    upper_bound(ForwardIterator first, ForwardIterator last, const T& value);
387
388template <class ForwardIterator, class T, class Compare>
389    ForwardIterator
390    upper_bound(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
391
392template <class ForwardIterator, class T>
393    pair<ForwardIterator, ForwardIterator>
394    equal_range(ForwardIterator first, ForwardIterator last, const T& value);
395
396template <class ForwardIterator, class T, class Compare>
397    pair<ForwardIterator, ForwardIterator>
398    equal_range(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
399
400template <class ForwardIterator, class T>
401    bool
402    binary_search(ForwardIterator first, ForwardIterator last, const T& value);
403
404template <class ForwardIterator, class T, class Compare>
405    bool
406    binary_search(ForwardIterator first, ForwardIterator last, const T& value, Compare comp);
407
408template <class InputIterator1, class InputIterator2, class OutputIterator>
409    OutputIterator
410    merge(InputIterator1 first1, InputIterator1 last1,
411          InputIterator2 first2, InputIterator2 last2, OutputIterator result);
412
413template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
414    OutputIterator
415    merge(InputIterator1 first1, InputIterator1 last1,
416          InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
417
418template <class BidirectionalIterator>
419    void
420    inplace_merge(BidirectionalIterator first, BidirectionalIterator middle, BidirectionalIterator last);
421
422template <class BidirectionalIterator, class Compare>
423    void
424    inplace_merge(BidirectionalIterator first, BidirectionalIterator middle, BidirectionalIterator last, Compare comp);
425
426template <class InputIterator1, class InputIterator2>
427    bool
428    includes(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2);
429
430template <class InputIterator1, class InputIterator2, class Compare>
431    bool
432    includes(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2, Compare comp);
433
434template <class InputIterator1, class InputIterator2, class OutputIterator>
435    OutputIterator
436    set_union(InputIterator1 first1, InputIterator1 last1,
437              InputIterator2 first2, InputIterator2 last2, OutputIterator result);
438
439template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
440    OutputIterator
441    set_union(InputIterator1 first1, InputIterator1 last1,
442              InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
443
444template <class InputIterator1, class InputIterator2, class OutputIterator>
445    OutputIterator
446    set_intersection(InputIterator1 first1, InputIterator1 last1,
447                     InputIterator2 first2, InputIterator2 last2, OutputIterator result);
448
449template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
450    OutputIterator
451    set_intersection(InputIterator1 first1, InputIterator1 last1,
452                     InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
453
454template <class InputIterator1, class InputIterator2, class OutputIterator>
455    OutputIterator
456    set_difference(InputIterator1 first1, InputIterator1 last1,
457                   InputIterator2 first2, InputIterator2 last2, OutputIterator result);
458
459template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
460    OutputIterator
461    set_difference(InputIterator1 first1, InputIterator1 last1,
462                   InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
463
464template <class InputIterator1, class InputIterator2, class OutputIterator>
465    OutputIterator
466    set_symmetric_difference(InputIterator1 first1, InputIterator1 last1,
467                             InputIterator2 first2, InputIterator2 last2, OutputIterator result);
468
469template <class InputIterator1, class InputIterator2, class OutputIterator, class Compare>
470    OutputIterator
471    set_symmetric_difference(InputIterator1 first1, InputIterator1 last1,
472                             InputIterator2 first2, InputIterator2 last2, OutputIterator result, Compare comp);
473
474template <class RandomAccessIterator>
475    void
476    push_heap(RandomAccessIterator first, RandomAccessIterator last);
477
478template <class RandomAccessIterator, class Compare>
479    void
480    push_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
481
482template <class RandomAccessIterator>
483    void
484    pop_heap(RandomAccessIterator first, RandomAccessIterator last);
485
486template <class RandomAccessIterator, class Compare>
487    void
488    pop_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
489
490template <class RandomAccessIterator>
491    void
492    make_heap(RandomAccessIterator first, RandomAccessIterator last);
493
494template <class RandomAccessIterator, class Compare>
495    void
496    make_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
497
498template <class RandomAccessIterator>
499    void
500    sort_heap(RandomAccessIterator first, RandomAccessIterator last);
501
502template <class RandomAccessIterator, class Compare>
503    void
504    sort_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
505
506template <class RandomAccessIterator>
507    bool
508    is_heap(RandomAccessIterator first, RandomAccessiterator last);
509
510template <class RandomAccessIterator, class Compare>
511    bool
512    is_heap(RandomAccessIterator first, RandomAccessiterator last, Compare comp);
513
514template <class RandomAccessIterator>
515    RandomAccessIterator
516    is_heap_until(RandomAccessIterator first, RandomAccessiterator last);
517
518template <class RandomAccessIterator, class Compare>
519    RandomAccessIterator
520    is_heap_until(RandomAccessIterator first, RandomAccessiterator last, Compare comp);
521
522template <class ForwardIterator>
523    ForwardIterator
524    min_element(ForwardIterator first, ForwardIterator last);  // constexpr in C++14
525
526template <class ForwardIterator, class Compare>
527    ForwardIterator
528    min_element(ForwardIterator first, ForwardIterator last, Compare comp);  // constexpr in C++14
529
530template <class T>
531    const T&
532    min(const T& a, const T& b);  // constexpr in C++14
533
534template <class T, class Compare>
535    const T&
536    min(const T& a, const T& b, Compare comp);  // constexpr in C++14
537
538template<class T>
539    T
540    min(initializer_list<T> t);  // constexpr in C++14
541
542template<class T, class Compare>
543    T
544    min(initializer_list<T> t, Compare comp);  // constexpr in C++14
545
546template <class ForwardIterator>
547    ForwardIterator
548    max_element(ForwardIterator first, ForwardIterator last);  // constexpr in C++14
549
550template <class ForwardIterator, class Compare>
551    ForwardIterator
552    max_element(ForwardIterator first, ForwardIterator last, Compare comp);  // constexpr in C++14
553
554template <class T>
555    const T&
556    max(const T& a, const T& b); // constexpr in C++14
557
558template <class T, class Compare>
559    const T&
560    max(const T& a, const T& b, Compare comp);  // constexpr in C++14
561
562template<class T>
563    T
564    max(initializer_list<T> t);  // constexpr in C++14
565
566template<class T, class Compare>
567    T
568    max(initializer_list<T> t, Compare comp);  // constexpr in C++14
569
570template<class ForwardIterator>
571    pair<ForwardIterator, ForwardIterator>
572    minmax_element(ForwardIterator first, ForwardIterator last);   // constexpr in C++14
573
574template<class ForwardIterator, class Compare>
575    pair<ForwardIterator, ForwardIterator>
576    minmax_element(ForwardIterator first, ForwardIterator last, Compare comp);   // constexpr in C++14
577
578template<class T>
579    pair<const T&, const T&>
580    minmax(const T& a, const T& b);  // constexpr in C++14
581
582template<class T, class Compare>
583    pair<const T&, const T&>
584    minmax(const T& a, const T& b, Compare comp);  // constexpr in C++14
585
586template<class T>
587    pair<T, T>
588    minmax(initializer_list<T> t);  // constexpr in C++14
589
590template<class T, class Compare>
591    pair<T, T>
592    minmax(initializer_list<T> t, Compare comp);  // constexpr in C++14
593
594template <class InputIterator1, class InputIterator2>
595    bool
596    lexicographical_compare(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2);
597
598template <class InputIterator1, class InputIterator2, class Compare>
599    bool
600    lexicographical_compare(InputIterator1 first1, InputIterator1 last1,
601                            InputIterator2 first2, InputIterator2 last2, Compare comp);
602
603template <class BidirectionalIterator>
604    bool
605    next_permutation(BidirectionalIterator first, BidirectionalIterator last);
606
607template <class BidirectionalIterator, class Compare>
608    bool
609    next_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp);
610
611template <class BidirectionalIterator>
612    bool
613    prev_permutation(BidirectionalIterator first, BidirectionalIterator last);
614
615template <class BidirectionalIterator, class Compare>
616    bool
617    prev_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp);
618
619}  // std
620
621*/
622
623#include <__config>
624#include <initializer_list>
625#include <type_traits>
626#include <cstring>
627#include <utility>
628#include <memory>
629#include <iterator>
630#include <cstddef>
631
632#if defined(__IBMCPP__)
633#include "support/ibm/support.h"
634#endif
635#if defined(_LIBCPP_MSVCRT) || defined(__MINGW32__)
636#include "support/win32/support.h"
637#endif
638
639#include <__undef_min_max>
640
641#include <__debug>
642
643#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
644#pragma GCC system_header
645#endif
646
647_LIBCPP_BEGIN_NAMESPACE_STD
648
649// I'd like to replace these with _VSTD::equal_to<void>, but can't because:
650//   * That only works with C++14 and later, and
651//   * We haven't included <functional> here.
652template <class _T1, class _T2 = _T1>
653struct __equal_to
654{
655    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
656    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T1& __x, const _T2& __y) const {return __x == __y;}
657    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T2& __x, const _T1& __y) const {return __x == __y;}
658    _LIBCPP_INLINE_VISIBILITY bool operator()(const _T2& __x, const _T2& __y) const {return __x == __y;}
659};
660
661template <class _T1>
662struct __equal_to<_T1, _T1>
663{
664    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
665    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
666};
667
668template <class _T1>
669struct __equal_to<const _T1, _T1>
670{
671    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
672    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
673};
674
675template <class _T1>
676struct __equal_to<_T1, const _T1>
677{
678    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
679    bool operator()(const _T1& __x, const _T1& __y) const {return __x == __y;}
680};
681
682template <class _T1, class _T2 = _T1>
683struct __less
684{
685    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
686    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
687
688    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
689    bool operator()(const _T1& __x, const _T2& __y) const {return __x < __y;}
690
691    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
692    bool operator()(const _T2& __x, const _T1& __y) const {return __x < __y;}
693
694    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
695    bool operator()(const _T2& __x, const _T2& __y) const {return __x < __y;}
696};
697
698template <class _T1>
699struct __less<_T1, _T1>
700{
701    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
702    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
703};
704
705template <class _T1>
706struct __less<const _T1, _T1>
707{
708    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
709    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
710};
711
712template <class _T1>
713struct __less<_T1, const _T1>
714{
715    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
716    bool operator()(const _T1& __x, const _T1& __y) const {return __x < __y;}
717};
718
719template <class _Predicate>
720class __negate
721{
722private:
723    _Predicate __p_;
724public:
725    _LIBCPP_INLINE_VISIBILITY __negate() {}
726
727    _LIBCPP_INLINE_VISIBILITY
728    explicit __negate(_Predicate __p) : __p_(__p) {}
729
730    template <class _T1>
731    _LIBCPP_INLINE_VISIBILITY
732    bool operator()(const _T1& __x) {return !__p_(__x);}
733
734    template <class _T1, class _T2>
735    _LIBCPP_INLINE_VISIBILITY
736    bool operator()(const _T1& __x, const _T2& __y) {return !__p_(__x, __y);}
737};
738
739#ifdef _LIBCPP_DEBUG
740
741template <class _Compare>
742struct __debug_less
743{
744    _Compare __comp_;
745    __debug_less(_Compare& __c) : __comp_(__c) {}
746    template <class _Tp, class _Up>
747    bool operator()(const _Tp& __x, const _Up& __y)
748    {
749        bool __r = __comp_(__x, __y);
750        if (__r)
751            _LIBCPP_ASSERT(!__comp_(__y, __x), "Comparator does not induce a strict weak ordering");
752        return __r;
753    }
754};
755
756#endif  // _LIBCPP_DEBUG
757
758// Precondition:  __x != 0
759inline _LIBCPP_INLINE_VISIBILITY
760unsigned
761__ctz(unsigned __x)
762{
763    return static_cast<unsigned>(__builtin_ctz(__x));
764}
765
766inline _LIBCPP_INLINE_VISIBILITY
767unsigned long
768__ctz(unsigned long __x)
769{
770    return static_cast<unsigned long>(__builtin_ctzl(__x));
771}
772
773inline _LIBCPP_INLINE_VISIBILITY
774unsigned long long
775__ctz(unsigned long long __x)
776{
777    return static_cast<unsigned long long>(__builtin_ctzll(__x));
778}
779
780// Precondition:  __x != 0
781inline _LIBCPP_INLINE_VISIBILITY
782unsigned
783__clz(unsigned __x)
784{
785    return static_cast<unsigned>(__builtin_clz(__x));
786}
787
788inline _LIBCPP_INLINE_VISIBILITY
789unsigned long
790__clz(unsigned long __x)
791{
792    return static_cast<unsigned long>(__builtin_clzl (__x));
793}
794
795inline _LIBCPP_INLINE_VISIBILITY
796unsigned long long
797__clz(unsigned long long __x)
798{
799    return static_cast<unsigned long long>(__builtin_clzll(__x));
800}
801
802inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned           __x) {return __builtin_popcount  (__x);}
803inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned      long __x) {return __builtin_popcountl (__x);}
804inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned long long __x) {return __builtin_popcountll(__x);}
805
806// all_of
807
808template <class _InputIterator, class _Predicate>
809inline _LIBCPP_INLINE_VISIBILITY
810bool
811all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
812{
813    for (; __first != __last; ++__first)
814        if (!__pred(*__first))
815            return false;
816    return true;
817}
818
819// any_of
820
821template <class _InputIterator, class _Predicate>
822inline _LIBCPP_INLINE_VISIBILITY
823bool
824any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
825{
826    for (; __first != __last; ++__first)
827        if (__pred(*__first))
828            return true;
829    return false;
830}
831
832// none_of
833
834template <class _InputIterator, class _Predicate>
835inline _LIBCPP_INLINE_VISIBILITY
836bool
837none_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)
838{
839    for (; __first != __last; ++__first)
840        if (__pred(*__first))
841            return false;
842    return true;
843}
844
845// for_each
846
847template <class _InputIterator, class _Function>
848inline _LIBCPP_INLINE_VISIBILITY
849_Function
850for_each(_InputIterator __first, _InputIterator __last, _Function __f)
851{
852    for (; __first != __last; ++__first)
853        __f(*__first);
854    return _LIBCPP_EXPLICIT_MOVE(__f);  // explicitly moved for (emulated) C++03
855}
856
857// find
858
859template <class _InputIterator, class _Tp>
860inline _LIBCPP_INLINE_VISIBILITY
861_InputIterator
862find(_InputIterator __first, _InputIterator __last, const _Tp& __value_)
863{
864    for (; __first != __last; ++__first)
865        if (*__first == __value_)
866            break;
867    return __first;
868}
869
870// find_if
871
872template <class _InputIterator, class _Predicate>
873inline _LIBCPP_INLINE_VISIBILITY
874_InputIterator
875find_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
876{
877    for (; __first != __last; ++__first)
878        if (__pred(*__first))
879            break;
880    return __first;
881}
882
883// find_if_not
884
885template<class _InputIterator, class _Predicate>
886inline _LIBCPP_INLINE_VISIBILITY
887_InputIterator
888find_if_not(_InputIterator __first, _InputIterator __last, _Predicate __pred)
889{
890    for (; __first != __last; ++__first)
891        if (!__pred(*__first))
892            break;
893    return __first;
894}
895
896// find_end
897
898template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
899_ForwardIterator1
900__find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
901           _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
902           forward_iterator_tag, forward_iterator_tag)
903{
904    // modeled after search algorithm
905    _ForwardIterator1 __r = __last1;  // __last1 is the "default" answer
906    if (__first2 == __last2)
907        return __r;
908    while (true)
909    {
910        while (true)
911        {
912            if (__first1 == __last1)         // if source exhausted return last correct answer
913                return __r;                  //    (or __last1 if never found)
914            if (__pred(*__first1, *__first2))
915                break;
916            ++__first1;
917        }
918        // *__first1 matches *__first2, now match elements after here
919        _ForwardIterator1 __m1 = __first1;
920        _ForwardIterator2 __m2 = __first2;
921        while (true)
922        {
923            if (++__m2 == __last2)
924            {                         // Pattern exhaused, record answer and search for another one
925                __r = __first1;
926                ++__first1;
927                break;
928            }
929            if (++__m1 == __last1)     // Source exhausted, return last answer
930                return __r;
931            if (!__pred(*__m1, *__m2))  // mismatch, restart with a new __first
932            {
933                ++__first1;
934                break;
935            }  // else there is a match, check next elements
936        }
937    }
938}
939
940template <class _BinaryPredicate, class _BidirectionalIterator1, class _BidirectionalIterator2>
941_BidirectionalIterator1
942__find_end(_BidirectionalIterator1 __first1, _BidirectionalIterator1 __last1,
943           _BidirectionalIterator2 __first2, _BidirectionalIterator2 __last2, _BinaryPredicate __pred,
944           bidirectional_iterator_tag, bidirectional_iterator_tag)
945{
946    // modeled after search algorithm (in reverse)
947    if (__first2 == __last2)
948        return __last1;  // Everything matches an empty sequence
949    _BidirectionalIterator1 __l1 = __last1;
950    _BidirectionalIterator2 __l2 = __last2;
951    --__l2;
952    while (true)
953    {
954        // Find last element in sequence 1 that matchs *(__last2-1), with a mininum of loop checks
955        while (true)
956        {
957            if (__first1 == __l1)  // return __last1 if no element matches *__first2
958                return __last1;
959            if (__pred(*--__l1, *__l2))
960                break;
961        }
962        // *__l1 matches *__l2, now match elements before here
963        _BidirectionalIterator1 __m1 = __l1;
964        _BidirectionalIterator2 __m2 = __l2;
965        while (true)
966        {
967            if (__m2 == __first2)  // If pattern exhausted, __m1 is the answer (works for 1 element pattern)
968                return __m1;
969            if (__m1 == __first1)  // Otherwise if source exhaused, pattern not found
970                return __last1;
971            if (!__pred(*--__m1, *--__m2))  // if there is a mismatch, restart with a new __l1
972            {
973                break;
974            }  // else there is a match, check next elements
975        }
976    }
977}
978
979template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
980_LIBCPP_CONSTEXPR_AFTER_CXX11 _RandomAccessIterator1
981__find_end(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
982           _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
983           random_access_iterator_tag, random_access_iterator_tag)
984{
985    // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
986    typename iterator_traits<_RandomAccessIterator2>::difference_type __len2 = __last2 - __first2;
987    if (__len2 == 0)
988        return __last1;
989    typename iterator_traits<_RandomAccessIterator1>::difference_type __len1 = __last1 - __first1;
990    if (__len1 < __len2)
991        return __last1;
992    const _RandomAccessIterator1 __s = __first1 + (__len2 - 1);  // End of pattern match can't go before here
993    _RandomAccessIterator1 __l1 = __last1;
994    _RandomAccessIterator2 __l2 = __last2;
995    --__l2;
996    while (true)
997    {
998        while (true)
999        {
1000            if (__s == __l1)
1001                return __last1;
1002            if (__pred(*--__l1, *__l2))
1003                break;
1004        }
1005        _RandomAccessIterator1 __m1 = __l1;
1006        _RandomAccessIterator2 __m2 = __l2;
1007        while (true)
1008        {
1009            if (__m2 == __first2)
1010                return __m1;
1011                                 // no need to check range on __m1 because __s guarantees we have enough source
1012            if (!__pred(*--__m1, *--__m2))
1013            {
1014                break;
1015            }
1016        }
1017    }
1018}
1019
1020template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1021inline _LIBCPP_INLINE_VISIBILITY
1022_ForwardIterator1
1023find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1024         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1025{
1026    return _VSTD::__find_end<typename add_lvalue_reference<_BinaryPredicate>::type>
1027                         (__first1, __last1, __first2, __last2, __pred,
1028                          typename iterator_traits<_ForwardIterator1>::iterator_category(),
1029                          typename iterator_traits<_ForwardIterator2>::iterator_category());
1030}
1031
1032template <class _ForwardIterator1, class _ForwardIterator2>
1033inline _LIBCPP_INLINE_VISIBILITY
1034_ForwardIterator1
1035find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1036         _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1037{
1038    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1039    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1040    return _VSTD::find_end(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1041}
1042
1043// find_first_of
1044
1045template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1046_LIBCPP_CONSTEXPR_AFTER_CXX11 _ForwardIterator1
1047__find_first_of_ce(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1048              _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1049{
1050    for (; __first1 != __last1; ++__first1)
1051        for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
1052            if (__pred(*__first1, *__j))
1053                return __first1;
1054    return __last1;
1055}
1056
1057
1058template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1059inline _LIBCPP_INLINE_VISIBILITY
1060_ForwardIterator1
1061find_first_of(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1062              _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1063{
1064    return _VSTD::__find_first_of_ce(__first1, __last1, __first2, __last2, __pred);
1065}
1066
1067template <class _ForwardIterator1, class _ForwardIterator2>
1068inline _LIBCPP_INLINE_VISIBILITY
1069_ForwardIterator1
1070find_first_of(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1071              _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1072{
1073    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1074    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1075    return _VSTD::__find_first_of_ce(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1076}
1077
1078// adjacent_find
1079
1080template <class _ForwardIterator, class _BinaryPredicate>
1081inline _LIBCPP_INLINE_VISIBILITY
1082_ForwardIterator
1083adjacent_find(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
1084{
1085    if (__first != __last)
1086    {
1087        _ForwardIterator __i = __first;
1088        while (++__i != __last)
1089        {
1090            if (__pred(*__first, *__i))
1091                return __first;
1092            __first = __i;
1093        }
1094    }
1095    return __last;
1096}
1097
1098template <class _ForwardIterator>
1099inline _LIBCPP_INLINE_VISIBILITY
1100_ForwardIterator
1101adjacent_find(_ForwardIterator __first, _ForwardIterator __last)
1102{
1103    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
1104    return _VSTD::adjacent_find(__first, __last, __equal_to<__v>());
1105}
1106
1107// count
1108
1109template <class _InputIterator, class _Tp>
1110inline _LIBCPP_INLINE_VISIBILITY
1111typename iterator_traits<_InputIterator>::difference_type
1112count(_InputIterator __first, _InputIterator __last, const _Tp& __value_)
1113{
1114    typename iterator_traits<_InputIterator>::difference_type __r(0);
1115    for (; __first != __last; ++__first)
1116        if (*__first == __value_)
1117            ++__r;
1118    return __r;
1119}
1120
1121// count_if
1122
1123template <class _InputIterator, class _Predicate>
1124inline _LIBCPP_INLINE_VISIBILITY
1125typename iterator_traits<_InputIterator>::difference_type
1126count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)
1127{
1128    typename iterator_traits<_InputIterator>::difference_type __r(0);
1129    for (; __first != __last; ++__first)
1130        if (__pred(*__first))
1131            ++__r;
1132    return __r;
1133}
1134
1135// mismatch
1136
1137template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1138inline _LIBCPP_INLINE_VISIBILITY
1139pair<_InputIterator1, _InputIterator2>
1140mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1141         _InputIterator2 __first2, _BinaryPredicate __pred)
1142{
1143    for (; __first1 != __last1; ++__first1, (void) ++__first2)
1144        if (!__pred(*__first1, *__first2))
1145            break;
1146    return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1147}
1148
1149template <class _InputIterator1, class _InputIterator2>
1150inline _LIBCPP_INLINE_VISIBILITY
1151pair<_InputIterator1, _InputIterator2>
1152mismatch(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2)
1153{
1154    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1155    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1156    return _VSTD::mismatch(__first1, __last1, __first2, __equal_to<__v1, __v2>());
1157}
1158
1159#if _LIBCPP_STD_VER > 11
1160template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1161inline _LIBCPP_INLINE_VISIBILITY
1162pair<_InputIterator1, _InputIterator2>
1163mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1164         _InputIterator2 __first2, _InputIterator2 __last2,
1165         _BinaryPredicate __pred)
1166{
1167    for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void) ++__first2)
1168        if (!__pred(*__first1, *__first2))
1169            break;
1170    return pair<_InputIterator1, _InputIterator2>(__first1, __first2);
1171}
1172
1173template <class _InputIterator1, class _InputIterator2>
1174inline _LIBCPP_INLINE_VISIBILITY
1175pair<_InputIterator1, _InputIterator2>
1176mismatch(_InputIterator1 __first1, _InputIterator1 __last1,
1177         _InputIterator2 __first2, _InputIterator2 __last2)
1178{
1179    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1180    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1181    return _VSTD::mismatch(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1182}
1183#endif
1184
1185// equal
1186
1187template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1188inline _LIBCPP_INLINE_VISIBILITY
1189bool
1190equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _BinaryPredicate __pred)
1191{
1192    for (; __first1 != __last1; ++__first1, (void) ++__first2)
1193        if (!__pred(*__first1, *__first2))
1194            return false;
1195    return true;
1196}
1197
1198template <class _InputIterator1, class _InputIterator2>
1199inline _LIBCPP_INLINE_VISIBILITY
1200bool
1201equal(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2)
1202{
1203    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1204    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1205    return _VSTD::equal(__first1, __last1, __first2, __equal_to<__v1, __v2>());
1206}
1207
1208#if _LIBCPP_STD_VER > 11
1209template <class _BinaryPredicate, class _InputIterator1, class _InputIterator2>
1210inline _LIBCPP_INLINE_VISIBILITY
1211bool
1212__equal(_InputIterator1 __first1, _InputIterator1 __last1,
1213        _InputIterator2 __first2, _InputIterator2 __last2, _BinaryPredicate __pred,
1214        input_iterator_tag, input_iterator_tag )
1215{
1216    for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void) ++__first2)
1217        if (!__pred(*__first1, *__first2))
1218            return false;
1219    return __first1 == __last1 && __first2 == __last2;
1220}
1221
1222template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1223inline _LIBCPP_INLINE_VISIBILITY
1224bool
1225__equal(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
1226        _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
1227      random_access_iterator_tag, random_access_iterator_tag )
1228{
1229    if ( _VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
1230        return false;
1231    return _VSTD::equal<_RandomAccessIterator1, _RandomAccessIterator2,
1232                        typename add_lvalue_reference<_BinaryPredicate>::type>
1233                       (__first1, __last1, __first2, __pred );
1234}
1235
1236template <class _InputIterator1, class _InputIterator2, class _BinaryPredicate>
1237inline _LIBCPP_INLINE_VISIBILITY
1238bool
1239equal(_InputIterator1 __first1, _InputIterator1 __last1,
1240      _InputIterator2 __first2, _InputIterator2 __last2, _BinaryPredicate __pred )
1241{
1242    return _VSTD::__equal<typename add_lvalue_reference<_BinaryPredicate>::type>
1243       (__first1, __last1, __first2, __last2, __pred,
1244        typename iterator_traits<_InputIterator1>::iterator_category(),
1245        typename iterator_traits<_InputIterator2>::iterator_category());
1246}
1247
1248template <class _InputIterator1, class _InputIterator2>
1249inline _LIBCPP_INLINE_VISIBILITY
1250bool
1251equal(_InputIterator1 __first1, _InputIterator1 __last1,
1252      _InputIterator2 __first2, _InputIterator2 __last2)
1253{
1254    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
1255    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
1256    return _VSTD::__equal(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>(),
1257        typename iterator_traits<_InputIterator1>::iterator_category(),
1258        typename iterator_traits<_InputIterator2>::iterator_category());
1259}
1260#endif
1261
1262// is_permutation
1263
1264template<class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1265bool
1266is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1267               _ForwardIterator2 __first2, _BinaryPredicate __pred)
1268{
1269    // shorten sequences as much as possible by lopping of any equal parts
1270    for (; __first1 != __last1; ++__first1, (void) ++__first2)
1271        if (!__pred(*__first1, *__first2))
1272            goto __not_done;
1273    return true;
1274__not_done:
1275    // __first1 != __last1 && *__first1 != *__first2
1276    typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
1277    _D1 __l1 = _VSTD::distance(__first1, __last1);
1278    if (__l1 == _D1(1))
1279        return false;
1280    _ForwardIterator2 __last2 = _VSTD::next(__first2, __l1);
1281    // For each element in [f1, l1) see if there are the same number of
1282    //    equal elements in [f2, l2)
1283    for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i)
1284    {
1285        // Have we already counted the number of *__i in [f1, l1)?
1286        for (_ForwardIterator1 __j = __first1; __j != __i; ++__j)
1287            if (__pred(*__j, *__i))
1288                goto __next_iter;
1289        {
1290            // Count number of *__i in [f2, l2)
1291            _D1 __c2 = 0;
1292            for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
1293                if (__pred(*__i, *__j))
1294                    ++__c2;
1295            if (__c2 == 0)
1296                return false;
1297            // Count number of *__i in [__i, l1) (we can start with 1)
1298            _D1 __c1 = 1;
1299            for (_ForwardIterator1 __j = _VSTD::next(__i); __j != __last1; ++__j)
1300                if (__pred(*__i, *__j))
1301                    ++__c1;
1302            if (__c1 != __c2)
1303                return false;
1304        }
1305__next_iter:;
1306    }
1307    return true;
1308}
1309
1310template<class _ForwardIterator1, class _ForwardIterator2>
1311inline _LIBCPP_INLINE_VISIBILITY
1312bool
1313is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1314               _ForwardIterator2 __first2)
1315{
1316    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1317    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1318    return _VSTD::is_permutation(__first1, __last1, __first2, __equal_to<__v1, __v2>());
1319}
1320
1321#if _LIBCPP_STD_VER > 11
1322template<class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
1323bool
1324__is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1325                 _ForwardIterator2 __first2, _ForwardIterator2 __last2,
1326                 _BinaryPredicate __pred,
1327                 forward_iterator_tag, forward_iterator_tag )
1328{
1329    // shorten sequences as much as possible by lopping of any equal parts
1330    for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void) ++__first2)
1331        if (!__pred(*__first1, *__first2))
1332            goto __not_done;
1333    return __first1 == __last1 && __first2 == __last2;
1334__not_done:
1335    // __first1 != __last1 && __first2 != __last2 && *__first1 != *__first2
1336    typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
1337    _D1 __l1 = _VSTD::distance(__first1, __last1);
1338
1339    typedef typename iterator_traits<_ForwardIterator2>::difference_type _D2;
1340    _D2 __l2 = _VSTD::distance(__first2, __last2);
1341    if (__l1 != __l2)
1342        return false;
1343
1344    // For each element in [f1, l1) see if there are the same number of
1345    //    equal elements in [f2, l2)
1346    for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i)
1347    {
1348        // Have we already counted the number of *__i in [f1, l1)?
1349        for (_ForwardIterator1 __j = __first1; __j != __i; ++__j)
1350            if (__pred(*__j, *__i))
1351                goto __next_iter;
1352        {
1353            // Count number of *__i in [f2, l2)
1354            _D1 __c2 = 0;
1355            for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
1356                if (__pred(*__i, *__j))
1357                    ++__c2;
1358            if (__c2 == 0)
1359                return false;
1360            // Count number of *__i in [__i, l1) (we can start with 1)
1361            _D1 __c1 = 1;
1362            for (_ForwardIterator1 __j = _VSTD::next(__i); __j != __last1; ++__j)
1363                if (__pred(*__i, *__j))
1364                    ++__c1;
1365            if (__c1 != __c2)
1366                return false;
1367        }
1368__next_iter:;
1369    }
1370    return true;
1371}
1372
1373template<class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1374bool
1375__is_permutation(_RandomAccessIterator1 __first1, _RandomAccessIterator2 __last1,
1376               _RandomAccessIterator1 __first2, _RandomAccessIterator2 __last2,
1377               _BinaryPredicate __pred,
1378               random_access_iterator_tag, random_access_iterator_tag )
1379{
1380    if ( _VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
1381        return false;
1382    return _VSTD::is_permutation<_RandomAccessIterator1, _RandomAccessIterator2,
1383                                 typename add_lvalue_reference<_BinaryPredicate>::type>
1384                                (__first1, __last1, __first2, __pred );
1385}
1386
1387template<class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1388inline _LIBCPP_INLINE_VISIBILITY
1389bool
1390is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1391               _ForwardIterator2 __first2, _ForwardIterator2 __last2,
1392               _BinaryPredicate __pred )
1393{
1394    return _VSTD::__is_permutation<typename add_lvalue_reference<_BinaryPredicate>::type>
1395       (__first1, __last1, __first2, __last2, __pred,
1396        typename iterator_traits<_ForwardIterator1>::iterator_category(),
1397        typename iterator_traits<_ForwardIterator2>::iterator_category());
1398}
1399
1400template<class _ForwardIterator1, class _ForwardIterator2>
1401inline _LIBCPP_INLINE_VISIBILITY
1402bool
1403is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1404               _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1405{
1406    typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
1407    typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
1408    return _VSTD::__is_permutation(__first1, __last1, __first2, __last2,
1409        __equal_to<__v1, __v2>(),
1410        typename iterator_traits<_ForwardIterator1>::iterator_category(),
1411        typename iterator_traits<_ForwardIterator2>::iterator_category());
1412}
1413#endif
1414
1415// search
1416
1417template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
1418_ForwardIterator1
1419__search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1420         _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred,
1421         forward_iterator_tag, forward_iterator_tag)
1422{
1423    if (__first2 == __last2)
1424        return __first1;  // Everything matches an empty sequence
1425    while (true)
1426    {
1427        // Find first element in sequence 1 that matchs *__first2, with a mininum of loop checks
1428        while (true)
1429        {
1430            if (__first1 == __last1)  // return __last1 if no element matches *__first2
1431                return __last1;
1432            if (__pred(*__first1, *__first2))
1433                break;
1434            ++__first1;
1435        }
1436        // *__first1 matches *__first2, now match elements after here
1437        _ForwardIterator1 __m1 = __first1;
1438        _ForwardIterator2 __m2 = __first2;
1439        while (true)
1440        {
1441            if (++__m2 == __last2)  // If pattern exhausted, __first1 is the answer (works for 1 element pattern)
1442                return __first1;
1443            if (++__m1 == __last1)  // Otherwise if source exhaused, pattern not found
1444                return __last1;
1445            if (!__pred(*__m1, *__m2))  // if there is a mismatch, restart with a new __first1
1446            {
1447                ++__first1;
1448                break;
1449            }  // else there is a match, check next elements
1450        }
1451    }
1452}
1453
1454template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
1455_LIBCPP_CONSTEXPR_AFTER_CXX11 _RandomAccessIterator1
1456__search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1,
1457           _RandomAccessIterator2 __first2, _RandomAccessIterator2 __last2, _BinaryPredicate __pred,
1458           random_access_iterator_tag, random_access_iterator_tag)
1459{
1460    typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _D1;
1461    typedef typename std::iterator_traits<_RandomAccessIterator2>::difference_type _D2;
1462    // Take advantage of knowing source and pattern lengths.  Stop short when source is smaller than pattern
1463    _D2 __len2 = __last2 - __first2;
1464    if (__len2 == 0)
1465        return __first1;
1466    _D1 __len1 = __last1 - __first1;
1467    if (__len1 < __len2)
1468        return __last1;
1469    const _RandomAccessIterator1 __s = __last1 - (__len2 - 1);  // Start of pattern match can't go beyond here
1470    while (true)
1471    {
1472#if !_LIBCPP_UNROLL_LOOPS
1473        while (true)
1474        {
1475            if (__first1 == __s)
1476                return __last1;
1477            if (__pred(*__first1, *__first2))
1478                break;
1479            ++__first1;
1480        }
1481#else  // !_LIBCPP_UNROLL_LOOPS
1482        for (_D1 __loop_unroll = (__s - __first1) / 4; __loop_unroll > 0; --__loop_unroll)
1483        {
1484            if (__pred(*__first1, *__first2))
1485                goto __phase2;
1486            if (__pred(*++__first1, *__first2))
1487                goto __phase2;
1488            if (__pred(*++__first1, *__first2))
1489                goto __phase2;
1490            if (__pred(*++__first1, *__first2))
1491                goto __phase2;
1492            ++__first1;
1493        }
1494        switch (__s - __first1)
1495        {
1496        case 3:
1497            if (__pred(*__first1, *__first2))
1498                break;
1499            ++__first1;
1500        case 2:
1501            if (__pred(*__first1, *__first2))
1502                break;
1503            ++__first1;
1504        case 1:
1505            if (__pred(*__first1, *__first2))
1506                break;
1507        case 0:
1508            return __last1;
1509        }
1510    __phase2:
1511#endif  // !_LIBCPP_UNROLL_LOOPS
1512        _RandomAccessIterator1 __m1 = __first1;
1513        _RandomAccessIterator2 __m2 = __first2;
1514#if !_LIBCPP_UNROLL_LOOPS
1515         while (true)
1516         {
1517             if (++__m2 == __last2)
1518                 return __first1;
1519             ++__m1;          // no need to check range on __m1 because __s guarantees we have enough source
1520             if (!__pred(*__m1, *__m2))
1521             {
1522                 ++__first1;
1523                 break;
1524             }
1525         }
1526#else  // !_LIBCPP_UNROLL_LOOPS
1527        ++__m2;
1528        ++__m1;
1529        for (_D2 __loop_unroll = (__last2 - __m2) / 4; __loop_unroll > 0; --__loop_unroll)
1530        {
1531            if (!__pred(*__m1, *__m2))
1532                goto __continue;
1533            if (!__pred(*++__m1, *++__m2))
1534                goto __continue;
1535            if (!__pred(*++__m1, *++__m2))
1536                goto __continue;
1537            if (!__pred(*++__m1, *++__m2))
1538                goto __continue;
1539            ++__m1;
1540            ++__m2;
1541        }
1542        switch (__last2 - __m2)
1543        {
1544        case 3:
1545            if (!__pred(*__m1, *__m2))
1546                break;
1547            ++__m1;
1548            ++__m2;
1549        case 2:
1550            if (!__pred(*__m1, *__m2))
1551                break;
1552            ++__m1;
1553            ++__m2;
1554        case 1:
1555            if (!__pred(*__m1, *__m2))
1556                break;
1557        case 0:
1558            return __first1;
1559        }
1560    __continue:
1561        ++__first1;
1562#endif  // !_LIBCPP_UNROLL_LOOPS
1563    }
1564}
1565
1566template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
1567inline _LIBCPP_INLINE_VISIBILITY
1568_ForwardIterator1
1569search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1570       _ForwardIterator2 __first2, _ForwardIterator2 __last2, _BinaryPredicate __pred)
1571{
1572    return _VSTD::__search<typename add_lvalue_reference<_BinaryPredicate>::type>
1573                         (__first1, __last1, __first2, __last2, __pred,
1574                          typename std::iterator_traits<_ForwardIterator1>::iterator_category(),
1575                          typename std::iterator_traits<_ForwardIterator2>::iterator_category());
1576}
1577
1578template <class _ForwardIterator1, class _ForwardIterator2>
1579inline _LIBCPP_INLINE_VISIBILITY
1580_ForwardIterator1
1581search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
1582       _ForwardIterator2 __first2, _ForwardIterator2 __last2)
1583{
1584    typedef typename std::iterator_traits<_ForwardIterator1>::value_type __v1;
1585    typedef typename std::iterator_traits<_ForwardIterator2>::value_type __v2;
1586    return _VSTD::search(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>());
1587}
1588
1589// search_n
1590
1591template <class _BinaryPredicate, class _ForwardIterator, class _Size, class _Tp>
1592_ForwardIterator
1593__search_n(_ForwardIterator __first, _ForwardIterator __last,
1594           _Size __count, const _Tp& __value_, _BinaryPredicate __pred, forward_iterator_tag)
1595{
1596    if (__count <= 0)
1597        return __first;
1598    while (true)
1599    {
1600        // Find first element in sequence that matchs __value_, with a mininum of loop checks
1601        while (true)
1602        {
1603            if (__first == __last)  // return __last if no element matches __value_
1604                return __last;
1605            if (__pred(*__first, __value_))
1606                break;
1607            ++__first;
1608        }
1609        // *__first matches __value_, now match elements after here
1610        _ForwardIterator __m = __first;
1611        _Size __c(0);
1612        while (true)
1613        {
1614            if (++__c == __count)  // If pattern exhausted, __first is the answer (works for 1 element pattern)
1615                return __first;
1616            if (++__m == __last)  // Otherwise if source exhaused, pattern not found
1617                return __last;
1618            if (!__pred(*__m, __value_))  // if there is a mismatch, restart with a new __first
1619            {
1620                __first = __m;
1621                ++__first;
1622                break;
1623            }  // else there is a match, check next elements
1624        }
1625    }
1626}
1627
1628template <class _BinaryPredicate, class _RandomAccessIterator, class _Size, class _Tp>
1629_RandomAccessIterator
1630__search_n(_RandomAccessIterator __first, _RandomAccessIterator __last,
1631           _Size __count, const _Tp& __value_, _BinaryPredicate __pred, random_access_iterator_tag)
1632{
1633    if (__count <= 0)
1634        return __first;
1635    _Size __len = static_cast<_Size>(__last - __first);
1636    if (__len < __count)
1637        return __last;
1638    const _RandomAccessIterator __s = __last - (__count - 1);  // Start of pattern match can't go beyond here
1639    while (true)
1640    {
1641        // Find first element in sequence that matchs __value_, with a mininum of loop checks
1642        while (true)
1643        {
1644            if (__first >= __s)  // return __last if no element matches __value_
1645                return __last;
1646            if (__pred(*__first, __value_))
1647                break;
1648            ++__first;
1649        }
1650        // *__first matches __value_, now match elements after here
1651        _RandomAccessIterator __m = __first;
1652        _Size __c(0);
1653        while (true)
1654        {
1655            if (++__c == __count)  // If pattern exhausted, __first is the answer (works for 1 element pattern)
1656                return __first;
1657             ++__m;          // no need to check range on __m because __s guarantees we have enough source
1658            if (!__pred(*__m, __value_))  // if there is a mismatch, restart with a new __first
1659            {
1660                __first = __m;
1661                ++__first;
1662                break;
1663            }  // else there is a match, check next elements
1664        }
1665    }
1666}
1667
1668template <class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate>
1669inline _LIBCPP_INLINE_VISIBILITY
1670_ForwardIterator
1671search_n(_ForwardIterator __first, _ForwardIterator __last,
1672         _Size __count, const _Tp& __value_, _BinaryPredicate __pred)
1673{
1674    return _VSTD::__search_n<typename add_lvalue_reference<_BinaryPredicate>::type>
1675           (__first, __last, __convert_to_integral(__count), __value_, __pred,
1676           typename iterator_traits<_ForwardIterator>::iterator_category());
1677}
1678
1679template <class _ForwardIterator, class _Size, class _Tp>
1680inline _LIBCPP_INLINE_VISIBILITY
1681_ForwardIterator
1682search_n(_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value_)
1683{
1684    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
1685    return _VSTD::search_n(__first, __last, __convert_to_integral(__count),
1686                           __value_, __equal_to<__v, _Tp>());
1687}
1688
1689// copy
1690template <class _Iter>
1691inline _LIBCPP_INLINE_VISIBILITY
1692_Iter
1693__unwrap_iter(_Iter __i)
1694{
1695    return __i;
1696}
1697
1698template <class _Tp>
1699inline _LIBCPP_INLINE_VISIBILITY
1700typename enable_if
1701<
1702    is_trivially_copy_assignable<_Tp>::value,
1703    _Tp*
1704>::type
1705__unwrap_iter(move_iterator<_Tp*> __i)
1706{
1707    return __i.base();
1708}
1709
1710#if _LIBCPP_DEBUG_LEVEL < 2
1711
1712template <class _Tp>
1713inline _LIBCPP_INLINE_VISIBILITY
1714typename enable_if
1715<
1716    is_trivially_copy_assignable<_Tp>::value,
1717    _Tp*
1718>::type
1719__unwrap_iter(__wrap_iter<_Tp*> __i)
1720{
1721    return __i.base();
1722}
1723
1724#endif  // _LIBCPP_DEBUG_LEVEL < 2
1725
1726template <class _InputIterator, class _OutputIterator>
1727inline _LIBCPP_INLINE_VISIBILITY
1728_OutputIterator
1729__copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1730{
1731    for (; __first != __last; ++__first, (void) ++__result)
1732        *__result = *__first;
1733    return __result;
1734}
1735
1736template <class _Tp, class _Up>
1737inline _LIBCPP_INLINE_VISIBILITY
1738typename enable_if
1739<
1740    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1741    is_trivially_copy_assignable<_Up>::value,
1742    _Up*
1743>::type
1744__copy(_Tp* __first, _Tp* __last, _Up* __result)
1745{
1746    const size_t __n = static_cast<size_t>(__last - __first);
1747    if (__n > 0)
1748        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1749    return __result + __n;
1750}
1751
1752template <class _InputIterator, class _OutputIterator>
1753inline _LIBCPP_INLINE_VISIBILITY
1754_OutputIterator
1755copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1756{
1757    return _VSTD::__copy(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
1758}
1759
1760// copy_backward
1761
1762template <class _BidirectionalIterator, class _OutputIterator>
1763inline _LIBCPP_INLINE_VISIBILITY
1764_OutputIterator
1765__copy_backward(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
1766{
1767    while (__first != __last)
1768        *--__result = *--__last;
1769    return __result;
1770}
1771
1772template <class _Tp, class _Up>
1773inline _LIBCPP_INLINE_VISIBILITY
1774typename enable_if
1775<
1776    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1777    is_trivially_copy_assignable<_Up>::value,
1778    _Up*
1779>::type
1780__copy_backward(_Tp* __first, _Tp* __last, _Up* __result)
1781{
1782    const size_t __n = static_cast<size_t>(__last - __first);
1783    if (__n > 0)
1784    {
1785        __result -= __n;
1786        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1787    }
1788    return __result;
1789}
1790
1791template <class _BidirectionalIterator1, class _BidirectionalIterator2>
1792inline _LIBCPP_INLINE_VISIBILITY
1793_BidirectionalIterator2
1794copy_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
1795              _BidirectionalIterator2 __result)
1796{
1797    return _VSTD::__copy_backward(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
1798}
1799
1800// copy_if
1801
1802template<class _InputIterator, class _OutputIterator, class _Predicate>
1803inline _LIBCPP_INLINE_VISIBILITY
1804_OutputIterator
1805copy_if(_InputIterator __first, _InputIterator __last,
1806        _OutputIterator __result, _Predicate __pred)
1807{
1808    for (; __first != __last; ++__first)
1809    {
1810        if (__pred(*__first))
1811        {
1812            *__result = *__first;
1813            ++__result;
1814        }
1815    }
1816    return __result;
1817}
1818
1819// copy_n
1820
1821template<class _InputIterator, class _Size, class _OutputIterator>
1822inline _LIBCPP_INLINE_VISIBILITY
1823typename enable_if
1824<
1825    __is_input_iterator<_InputIterator>::value &&
1826   !__is_random_access_iterator<_InputIterator>::value,
1827    _OutputIterator
1828>::type
1829copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
1830{
1831    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
1832    _IntegralSize __n = __orig_n;
1833    if (__n > 0)
1834    {
1835        *__result = *__first;
1836        ++__result;
1837        for (--__n; __n > 0; --__n)
1838        {
1839            ++__first;
1840            *__result = *__first;
1841            ++__result;
1842        }
1843    }
1844    return __result;
1845}
1846
1847template<class _InputIterator, class _Size, class _OutputIterator>
1848inline _LIBCPP_INLINE_VISIBILITY
1849typename enable_if
1850<
1851    __is_random_access_iterator<_InputIterator>::value,
1852    _OutputIterator
1853>::type
1854copy_n(_InputIterator __first, _Size __orig_n, _OutputIterator __result)
1855{
1856    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
1857    _IntegralSize __n = __orig_n;
1858    return _VSTD::copy(__first, __first + __n, __result);
1859}
1860
1861// move
1862
1863template <class _InputIterator, class _OutputIterator>
1864inline _LIBCPP_INLINE_VISIBILITY
1865_OutputIterator
1866__move(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1867{
1868    for (; __first != __last; ++__first, (void) ++__result)
1869        *__result = _VSTD::move(*__first);
1870    return __result;
1871}
1872
1873template <class _Tp, class _Up>
1874inline _LIBCPP_INLINE_VISIBILITY
1875typename enable_if
1876<
1877    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1878    is_trivially_copy_assignable<_Up>::value,
1879    _Up*
1880>::type
1881__move(_Tp* __first, _Tp* __last, _Up* __result)
1882{
1883    const size_t __n = static_cast<size_t>(__last - __first);
1884    if (__n > 0)
1885        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1886    return __result + __n;
1887}
1888
1889template <class _InputIterator, class _OutputIterator>
1890inline _LIBCPP_INLINE_VISIBILITY
1891_OutputIterator
1892move(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1893{
1894    return _VSTD::__move(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
1895}
1896
1897// move_backward
1898
1899template <class _InputIterator, class _OutputIterator>
1900inline _LIBCPP_INLINE_VISIBILITY
1901_OutputIterator
1902__move_backward(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
1903{
1904    while (__first != __last)
1905        *--__result = _VSTD::move(*--__last);
1906    return __result;
1907}
1908
1909template <class _Tp, class _Up>
1910inline _LIBCPP_INLINE_VISIBILITY
1911typename enable_if
1912<
1913    is_same<typename remove_const<_Tp>::type, _Up>::value &&
1914    is_trivially_copy_assignable<_Up>::value,
1915    _Up*
1916>::type
1917__move_backward(_Tp* __first, _Tp* __last, _Up* __result)
1918{
1919    const size_t __n = static_cast<size_t>(__last - __first);
1920    if (__n > 0)
1921    {
1922        __result -= __n;
1923        _VSTD::memmove(__result, __first, __n * sizeof(_Up));
1924    }
1925    return __result;
1926}
1927
1928template <class _BidirectionalIterator1, class _BidirectionalIterator2>
1929inline _LIBCPP_INLINE_VISIBILITY
1930_BidirectionalIterator2
1931move_backward(_BidirectionalIterator1 __first, _BidirectionalIterator1 __last,
1932              _BidirectionalIterator2 __result)
1933{
1934    return _VSTD::__move_backward(__unwrap_iter(__first), __unwrap_iter(__last), __unwrap_iter(__result));
1935}
1936
1937// iter_swap
1938
1939// moved to <type_traits> for better swap / noexcept support
1940
1941// transform
1942
1943template <class _InputIterator, class _OutputIterator, class _UnaryOperation>
1944inline _LIBCPP_INLINE_VISIBILITY
1945_OutputIterator
1946transform(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _UnaryOperation __op)
1947{
1948    for (; __first != __last; ++__first, (void) ++__result)
1949        *__result = __op(*__first);
1950    return __result;
1951}
1952
1953template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _BinaryOperation>
1954inline _LIBCPP_INLINE_VISIBILITY
1955_OutputIterator
1956transform(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2,
1957          _OutputIterator __result, _BinaryOperation __binary_op)
1958{
1959    for (; __first1 != __last1; ++__first1, (void) ++__first2, ++__result)
1960        *__result = __binary_op(*__first1, *__first2);
1961    return __result;
1962}
1963
1964// replace
1965
1966template <class _ForwardIterator, class _Tp>
1967inline _LIBCPP_INLINE_VISIBILITY
1968void
1969replace(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __old_value, const _Tp& __new_value)
1970{
1971    for (; __first != __last; ++__first)
1972        if (*__first == __old_value)
1973            *__first = __new_value;
1974}
1975
1976// replace_if
1977
1978template <class _ForwardIterator, class _Predicate, class _Tp>
1979inline _LIBCPP_INLINE_VISIBILITY
1980void
1981replace_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, const _Tp& __new_value)
1982{
1983    for (; __first != __last; ++__first)
1984        if (__pred(*__first))
1985            *__first = __new_value;
1986}
1987
1988// replace_copy
1989
1990template <class _InputIterator, class _OutputIterator, class _Tp>
1991inline _LIBCPP_INLINE_VISIBILITY
1992_OutputIterator
1993replace_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
1994             const _Tp& __old_value, const _Tp& __new_value)
1995{
1996    for (; __first != __last; ++__first, (void) ++__result)
1997        if (*__first == __old_value)
1998            *__result = __new_value;
1999        else
2000            *__result = *__first;
2001    return __result;
2002}
2003
2004// replace_copy_if
2005
2006template <class _InputIterator, class _OutputIterator, class _Predicate, class _Tp>
2007inline _LIBCPP_INLINE_VISIBILITY
2008_OutputIterator
2009replace_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
2010                _Predicate __pred, const _Tp& __new_value)
2011{
2012    for (; __first != __last; ++__first, (void) ++__result)
2013        if (__pred(*__first))
2014            *__result = __new_value;
2015        else
2016            *__result = *__first;
2017    return __result;
2018}
2019
2020// fill_n
2021
2022template <class _OutputIterator, class _Size, class _Tp>
2023inline _LIBCPP_INLINE_VISIBILITY
2024_OutputIterator
2025__fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
2026{
2027    for (; __n > 0; ++__first, (void) --__n)
2028        *__first = __value_;
2029    return __first;
2030}
2031
2032template <class _Tp, class _Size, class _Up>
2033inline _LIBCPP_INLINE_VISIBILITY
2034typename enable_if
2035<
2036    is_integral<_Tp>::value && sizeof(_Tp) == 1 &&
2037    !is_same<_Tp, bool>::value &&
2038    is_integral<_Up>::value && sizeof(_Up) == 1,
2039    _Tp*
2040>::type
2041__fill_n(_Tp* __first, _Size __n,_Up __value_)
2042{
2043    if (__n > 0)
2044        _VSTD::memset(__first, (unsigned char)__value_, (size_t)(__n));
2045    return __first + __n;
2046}
2047
2048template <class _OutputIterator, class _Size, class _Tp>
2049inline _LIBCPP_INLINE_VISIBILITY
2050_OutputIterator
2051fill_n(_OutputIterator __first, _Size __n, const _Tp& __value_)
2052{
2053   return _VSTD::__fill_n(__first, __convert_to_integral(__n), __value_);
2054}
2055
2056// fill
2057
2058template <class _ForwardIterator, class _Tp>
2059inline _LIBCPP_INLINE_VISIBILITY
2060void
2061__fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, forward_iterator_tag)
2062{
2063    for (; __first != __last; ++__first)
2064        *__first = __value_;
2065}
2066
2067template <class _RandomAccessIterator, class _Tp>
2068inline _LIBCPP_INLINE_VISIBILITY
2069void
2070__fill(_RandomAccessIterator __first, _RandomAccessIterator __last, const _Tp& __value_, random_access_iterator_tag)
2071{
2072    _VSTD::fill_n(__first, __last - __first, __value_);
2073}
2074
2075template <class _ForwardIterator, class _Tp>
2076inline _LIBCPP_INLINE_VISIBILITY
2077void
2078fill(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
2079{
2080    _VSTD::__fill(__first, __last, __value_, typename iterator_traits<_ForwardIterator>::iterator_category());
2081}
2082
2083// generate
2084
2085template <class _ForwardIterator, class _Generator>
2086inline _LIBCPP_INLINE_VISIBILITY
2087void
2088generate(_ForwardIterator __first, _ForwardIterator __last, _Generator __gen)
2089{
2090    for (; __first != __last; ++__first)
2091        *__first = __gen();
2092}
2093
2094// generate_n
2095
2096template <class _OutputIterator, class _Size, class _Generator>
2097inline _LIBCPP_INLINE_VISIBILITY
2098_OutputIterator
2099generate_n(_OutputIterator __first, _Size __orig_n, _Generator __gen)
2100{
2101    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
2102    _IntegralSize __n = __orig_n;
2103    for (; __n > 0; ++__first, (void) --__n)
2104        *__first = __gen();
2105    return __first;
2106}
2107
2108// remove
2109
2110template <class _ForwardIterator, class _Tp>
2111_ForwardIterator
2112remove(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
2113{
2114    __first = _VSTD::find(__first, __last, __value_);
2115    if (__first != __last)
2116    {
2117        _ForwardIterator __i = __first;
2118        while (++__i != __last)
2119        {
2120            if (!(*__i == __value_))
2121            {
2122                *__first = _VSTD::move(*__i);
2123                ++__first;
2124            }
2125        }
2126    }
2127    return __first;
2128}
2129
2130// remove_if
2131
2132template <class _ForwardIterator, class _Predicate>
2133_ForwardIterator
2134remove_if(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
2135{
2136    __first = _VSTD::find_if<_ForwardIterator, typename add_lvalue_reference<_Predicate>::type>
2137                           (__first, __last, __pred);
2138    if (__first != __last)
2139    {
2140        _ForwardIterator __i = __first;
2141        while (++__i != __last)
2142        {
2143            if (!__pred(*__i))
2144            {
2145                *__first = _VSTD::move(*__i);
2146                ++__first;
2147            }
2148        }
2149    }
2150    return __first;
2151}
2152
2153// remove_copy
2154
2155template <class _InputIterator, class _OutputIterator, class _Tp>
2156inline _LIBCPP_INLINE_VISIBILITY
2157_OutputIterator
2158remove_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, const _Tp& __value_)
2159{
2160    for (; __first != __last; ++__first)
2161    {
2162        if (!(*__first == __value_))
2163        {
2164            *__result = *__first;
2165            ++__result;
2166        }
2167    }
2168    return __result;
2169}
2170
2171// remove_copy_if
2172
2173template <class _InputIterator, class _OutputIterator, class _Predicate>
2174inline _LIBCPP_INLINE_VISIBILITY
2175_OutputIterator
2176remove_copy_if(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _Predicate __pred)
2177{
2178    for (; __first != __last; ++__first)
2179    {
2180        if (!__pred(*__first))
2181        {
2182            *__result = *__first;
2183            ++__result;
2184        }
2185    }
2186    return __result;
2187}
2188
2189// unique
2190
2191template <class _ForwardIterator, class _BinaryPredicate>
2192_ForwardIterator
2193unique(_ForwardIterator __first, _ForwardIterator __last, _BinaryPredicate __pred)
2194{
2195    __first = _VSTD::adjacent_find<_ForwardIterator, typename add_lvalue_reference<_BinaryPredicate>::type>
2196                                 (__first, __last, __pred);
2197    if (__first != __last)
2198    {
2199        // ...  a  a  ?  ...
2200        //      f     i
2201        _ForwardIterator __i = __first;
2202        for (++__i; ++__i != __last;)
2203            if (!__pred(*__first, *__i))
2204                *++__first = _VSTD::move(*__i);
2205        ++__first;
2206    }
2207    return __first;
2208}
2209
2210template <class _ForwardIterator>
2211inline _LIBCPP_INLINE_VISIBILITY
2212_ForwardIterator
2213unique(_ForwardIterator __first, _ForwardIterator __last)
2214{
2215    typedef typename iterator_traits<_ForwardIterator>::value_type __v;
2216    return _VSTD::unique(__first, __last, __equal_to<__v>());
2217}
2218
2219// unique_copy
2220
2221template <class _BinaryPredicate, class _InputIterator, class _OutputIterator>
2222_OutputIterator
2223__unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred,
2224              input_iterator_tag, output_iterator_tag)
2225{
2226    if (__first != __last)
2227    {
2228        typename iterator_traits<_InputIterator>::value_type __t(*__first);
2229        *__result = __t;
2230        ++__result;
2231        while (++__first != __last)
2232        {
2233            if (!__pred(__t, *__first))
2234            {
2235                __t = *__first;
2236                *__result = __t;
2237                ++__result;
2238            }
2239        }
2240    }
2241    return __result;
2242}
2243
2244template <class _BinaryPredicate, class _ForwardIterator, class _OutputIterator>
2245_OutputIterator
2246__unique_copy(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __result, _BinaryPredicate __pred,
2247              forward_iterator_tag, output_iterator_tag)
2248{
2249    if (__first != __last)
2250    {
2251        _ForwardIterator __i = __first;
2252        *__result = *__i;
2253        ++__result;
2254        while (++__first != __last)
2255        {
2256            if (!__pred(*__i, *__first))
2257            {
2258                *__result = *__first;
2259                ++__result;
2260                __i = __first;
2261            }
2262        }
2263    }
2264    return __result;
2265}
2266
2267template <class _BinaryPredicate, class _InputIterator, class _ForwardIterator>
2268_ForwardIterator
2269__unique_copy(_InputIterator __first, _InputIterator __last, _ForwardIterator __result, _BinaryPredicate __pred,
2270              input_iterator_tag, forward_iterator_tag)
2271{
2272    if (__first != __last)
2273    {
2274        *__result = *__first;
2275        while (++__first != __last)
2276            if (!__pred(*__result, *__first))
2277                *++__result = *__first;
2278        ++__result;
2279    }
2280    return __result;
2281}
2282
2283template <class _InputIterator, class _OutputIterator, class _BinaryPredicate>
2284inline _LIBCPP_INLINE_VISIBILITY
2285_OutputIterator
2286unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, _BinaryPredicate __pred)
2287{
2288    return _VSTD::__unique_copy<typename add_lvalue_reference<_BinaryPredicate>::type>
2289                              (__first, __last, __result, __pred,
2290                               typename iterator_traits<_InputIterator>::iterator_category(),
2291                               typename iterator_traits<_OutputIterator>::iterator_category());
2292}
2293
2294template <class _InputIterator, class _OutputIterator>
2295inline _LIBCPP_INLINE_VISIBILITY
2296_OutputIterator
2297unique_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
2298{
2299    typedef typename iterator_traits<_InputIterator>::value_type __v;
2300    return _VSTD::unique_copy(__first, __last, __result, __equal_to<__v>());
2301}
2302
2303// reverse
2304
2305template <class _BidirectionalIterator>
2306inline _LIBCPP_INLINE_VISIBILITY
2307void
2308__reverse(_BidirectionalIterator __first, _BidirectionalIterator __last, bidirectional_iterator_tag)
2309{
2310    while (__first != __last)
2311    {
2312        if (__first == --__last)
2313            break;
2314        _VSTD::iter_swap(__first, __last);
2315        ++__first;
2316    }
2317}
2318
2319template <class _RandomAccessIterator>
2320inline _LIBCPP_INLINE_VISIBILITY
2321void
2322__reverse(_RandomAccessIterator __first, _RandomAccessIterator __last, random_access_iterator_tag)
2323{
2324    if (__first != __last)
2325        for (; __first < --__last; ++__first)
2326            _VSTD::iter_swap(__first, __last);
2327}
2328
2329template <class _BidirectionalIterator>
2330inline _LIBCPP_INLINE_VISIBILITY
2331void
2332reverse(_BidirectionalIterator __first, _BidirectionalIterator __last)
2333{
2334    _VSTD::__reverse(__first, __last, typename iterator_traits<_BidirectionalIterator>::iterator_category());
2335}
2336
2337// reverse_copy
2338
2339template <class _BidirectionalIterator, class _OutputIterator>
2340inline _LIBCPP_INLINE_VISIBILITY
2341_OutputIterator
2342reverse_copy(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)
2343{
2344    for (; __first != __last; ++__result)
2345        *__result = *--__last;
2346    return __result;
2347}
2348
2349// rotate
2350
2351template <class _ForwardIterator>
2352_ForwardIterator
2353__rotate_left(_ForwardIterator __first, _ForwardIterator __last)
2354{
2355    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
2356    value_type __tmp = _VSTD::move(*__first);
2357    _ForwardIterator __lm1 = _VSTD::move(_VSTD::next(__first), __last, __first);
2358    *__lm1 = _VSTD::move(__tmp);
2359    return __lm1;
2360}
2361
2362template <class _BidirectionalIterator>
2363_BidirectionalIterator
2364__rotate_right(_BidirectionalIterator __first, _BidirectionalIterator __last)
2365{
2366    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
2367    _BidirectionalIterator __lm1 = _VSTD::prev(__last);
2368    value_type __tmp = _VSTD::move(*__lm1);
2369    _BidirectionalIterator __fp1 = _VSTD::move_backward(__first, __lm1, __last);
2370    *__first = _VSTD::move(__tmp);
2371    return __fp1;
2372}
2373
2374template <class _ForwardIterator>
2375_ForwardIterator
2376__rotate_forward(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
2377{
2378    _ForwardIterator __i = __middle;
2379    while (true)
2380    {
2381        swap(*__first, *__i);
2382        ++__first;
2383        if (++__i == __last)
2384            break;
2385        if (__first == __middle)
2386            __middle = __i;
2387    }
2388    _ForwardIterator __r = __first;
2389    if (__first != __middle)
2390    {
2391        __i = __middle;
2392        while (true)
2393        {
2394            swap(*__first, *__i);
2395            ++__first;
2396            if (++__i == __last)
2397            {
2398                if (__first == __middle)
2399                    break;
2400                __i = __middle;
2401            }
2402            else if (__first == __middle)
2403                __middle = __i;
2404        }
2405    }
2406    return __r;
2407}
2408
2409template<typename _Integral>
2410inline _LIBCPP_INLINE_VISIBILITY
2411_Integral
2412__gcd(_Integral __x, _Integral __y)
2413{
2414    do
2415    {
2416        _Integral __t = __x % __y;
2417        __x = __y;
2418        __y = __t;
2419    } while (__y);
2420    return __x;
2421}
2422
2423template<typename _RandomAccessIterator>
2424_RandomAccessIterator
2425__rotate_gcd(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)
2426{
2427    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
2428    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
2429
2430    const difference_type __m1 = __middle - __first;
2431    const difference_type __m2 = __last - __middle;
2432    if (__m1 == __m2)
2433    {
2434        _VSTD::swap_ranges(__first, __middle, __middle);
2435        return __middle;
2436    }
2437    const difference_type __g = _VSTD::__gcd(__m1, __m2);
2438    for (_RandomAccessIterator __p = __first + __g; __p != __first;)
2439    {
2440        value_type __t(_VSTD::move(*--__p));
2441        _RandomAccessIterator __p1 = __p;
2442        _RandomAccessIterator __p2 = __p1 + __m1;
2443        do
2444        {
2445            *__p1 = _VSTD::move(*__p2);
2446            __p1 = __p2;
2447            const difference_type __d = __last - __p2;
2448            if (__m1 < __d)
2449                __p2 += __m1;
2450            else
2451                __p2 = __first + (__m1 - __d);
2452        } while (__p2 != __p);
2453        *__p1 = _VSTD::move(__t);
2454    }
2455    return __first + __m2;
2456}
2457
2458template <class _ForwardIterator>
2459inline _LIBCPP_INLINE_VISIBILITY
2460_ForwardIterator
2461__rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last,
2462         _VSTD::forward_iterator_tag)
2463{
2464    typedef typename _VSTD::iterator_traits<_ForwardIterator>::value_type value_type;
2465    if (_VSTD::is_trivially_move_assignable<value_type>::value)
2466    {
2467        if (_VSTD::next(__first) == __middle)
2468            return _VSTD::__rotate_left(__first, __last);
2469    }
2470    return _VSTD::__rotate_forward(__first, __middle, __last);
2471}
2472
2473template <class _BidirectionalIterator>
2474inline _LIBCPP_INLINE_VISIBILITY
2475_BidirectionalIterator
2476__rotate(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
2477         _VSTD::bidirectional_iterator_tag)
2478{
2479    typedef typename _VSTD::iterator_traits<_BidirectionalIterator>::value_type value_type;
2480    if (_VSTD::is_trivially_move_assignable<value_type>::value)
2481    {
2482        if (_VSTD::next(__first) == __middle)
2483            return _VSTD::__rotate_left(__first, __last);
2484        if (_VSTD::next(__middle) == __last)
2485            return _VSTD::__rotate_right(__first, __last);
2486    }
2487    return _VSTD::__rotate_forward(__first, __middle, __last);
2488}
2489
2490template <class _RandomAccessIterator>
2491inline _LIBCPP_INLINE_VISIBILITY
2492_RandomAccessIterator
2493__rotate(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
2494         _VSTD::random_access_iterator_tag)
2495{
2496    typedef typename _VSTD::iterator_traits<_RandomAccessIterator>::value_type value_type;
2497    if (_VSTD::is_trivially_move_assignable<value_type>::value)
2498    {
2499        if (_VSTD::next(__first) == __middle)
2500            return _VSTD::__rotate_left(__first, __last);
2501        if (_VSTD::next(__middle) == __last)
2502            return _VSTD::__rotate_right(__first, __last);
2503        return _VSTD::__rotate_gcd(__first, __middle, __last);
2504    }
2505    return _VSTD::__rotate_forward(__first, __middle, __last);
2506}
2507
2508template <class _ForwardIterator>
2509inline _LIBCPP_INLINE_VISIBILITY
2510_ForwardIterator
2511rotate(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last)
2512{
2513    if (__first == __middle)
2514        return __last;
2515    if (__middle == __last)
2516        return __first;
2517    return _VSTD::__rotate(__first, __middle, __last,
2518                           typename _VSTD::iterator_traits<_ForwardIterator>::iterator_category());
2519}
2520
2521// rotate_copy
2522
2523template <class _ForwardIterator, class _OutputIterator>
2524inline _LIBCPP_INLINE_VISIBILITY
2525_OutputIterator
2526rotate_copy(_ForwardIterator __first, _ForwardIterator __middle, _ForwardIterator __last, _OutputIterator __result)
2527{
2528    return _VSTD::copy(__first, __middle, _VSTD::copy(__middle, __last, __result));
2529}
2530
2531// min_element
2532
2533template <class _ForwardIterator, class _Compare>
2534inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2535_ForwardIterator
2536min_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2537{
2538    if (__first != __last)
2539    {
2540        _ForwardIterator __i = __first;
2541        while (++__i != __last)
2542            if (__comp(*__i, *__first))
2543                __first = __i;
2544    }
2545    return __first;
2546}
2547
2548template <class _ForwardIterator>
2549inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2550_ForwardIterator
2551min_element(_ForwardIterator __first, _ForwardIterator __last)
2552{
2553    return _VSTD::min_element(__first, __last,
2554              __less<typename iterator_traits<_ForwardIterator>::value_type>());
2555}
2556
2557// min
2558
2559template <class _Tp, class _Compare>
2560inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2561const _Tp&
2562min(const _Tp& __a, const _Tp& __b, _Compare __comp)
2563{
2564    return __comp(__b, __a) ? __b : __a;
2565}
2566
2567template <class _Tp>
2568inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2569const _Tp&
2570min(const _Tp& __a, const _Tp& __b)
2571{
2572    return _VSTD::min(__a, __b, __less<_Tp>());
2573}
2574
2575#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2576
2577template<class _Tp, class _Compare>
2578inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2579_Tp
2580min(initializer_list<_Tp> __t, _Compare __comp)
2581{
2582    return *_VSTD::min_element(__t.begin(), __t.end(), __comp);
2583}
2584
2585template<class _Tp>
2586inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2587_Tp
2588min(initializer_list<_Tp> __t)
2589{
2590    return *_VSTD::min_element(__t.begin(), __t.end(), __less<_Tp>());
2591}
2592
2593#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2594
2595// max_element
2596
2597template <class _ForwardIterator, class _Compare>
2598inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2599_ForwardIterator
2600max_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2601{
2602    if (__first != __last)
2603    {
2604        _ForwardIterator __i = __first;
2605        while (++__i != __last)
2606            if (__comp(*__first, *__i))
2607                __first = __i;
2608    }
2609    return __first;
2610}
2611
2612
2613template <class _ForwardIterator>
2614inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2615_ForwardIterator
2616max_element(_ForwardIterator __first, _ForwardIterator __last)
2617{
2618    return _VSTD::max_element(__first, __last,
2619              __less<typename iterator_traits<_ForwardIterator>::value_type>());
2620}
2621
2622// max
2623
2624template <class _Tp, class _Compare>
2625inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2626const _Tp&
2627max(const _Tp& __a, const _Tp& __b, _Compare __comp)
2628{
2629    return __comp(__a, __b) ? __b : __a;
2630}
2631
2632template <class _Tp>
2633inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2634const _Tp&
2635max(const _Tp& __a, const _Tp& __b)
2636{
2637    return _VSTD::max(__a, __b, __less<_Tp>());
2638}
2639
2640#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2641
2642template<class _Tp, class _Compare>
2643inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2644_Tp
2645max(initializer_list<_Tp> __t, _Compare __comp)
2646{
2647    return *_VSTD::max_element(__t.begin(), __t.end(), __comp);
2648}
2649
2650template<class _Tp>
2651inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2652_Tp
2653max(initializer_list<_Tp> __t)
2654{
2655    return *_VSTD::max_element(__t.begin(), __t.end(), __less<_Tp>());
2656}
2657
2658#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2659
2660// minmax_element
2661
2662template <class _ForwardIterator, class _Compare>
2663_LIBCPP_CONSTEXPR_AFTER_CXX11
2664std::pair<_ForwardIterator, _ForwardIterator>
2665minmax_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
2666{
2667  std::pair<_ForwardIterator, _ForwardIterator> __result(__first, __first);
2668  if (__first != __last)
2669  {
2670      if (++__first != __last)
2671      {
2672          if (__comp(*__first, *__result.first))
2673              __result.first = __first;
2674          else
2675              __result.second = __first;
2676          while (++__first != __last)
2677          {
2678              _ForwardIterator __i = __first;
2679              if (++__first == __last)
2680              {
2681                  if (__comp(*__i, *__result.first))
2682                      __result.first = __i;
2683                  else if (!__comp(*__i, *__result.second))
2684                      __result.second = __i;
2685                  break;
2686              }
2687              else
2688              {
2689                  if (__comp(*__first, *__i))
2690                  {
2691                      if (__comp(*__first, *__result.first))
2692                          __result.first = __first;
2693                      if (!__comp(*__i, *__result.second))
2694                          __result.second = __i;
2695                  }
2696                  else
2697                  {
2698                      if (__comp(*__i, *__result.first))
2699                          __result.first = __i;
2700                      if (!__comp(*__first, *__result.second))
2701                          __result.second = __first;
2702                  }
2703              }
2704          }
2705      }
2706  }
2707  return __result;
2708}
2709
2710template <class _ForwardIterator>
2711inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2712std::pair<_ForwardIterator, _ForwardIterator>
2713minmax_element(_ForwardIterator __first, _ForwardIterator __last)
2714{
2715    return _VSTD::minmax_element(__first, __last,
2716              __less<typename iterator_traits<_ForwardIterator>::value_type>());
2717}
2718
2719// minmax
2720
2721template<class _Tp, class _Compare>
2722inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2723pair<const _Tp&, const _Tp&>
2724minmax(const _Tp& __a, const _Tp& __b, _Compare __comp)
2725{
2726    return __comp(__b, __a) ? pair<const _Tp&, const _Tp&>(__b, __a) :
2727                              pair<const _Tp&, const _Tp&>(__a, __b);
2728}
2729
2730template<class _Tp>
2731inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2732pair<const _Tp&, const _Tp&>
2733minmax(const _Tp& __a, const _Tp& __b)
2734{
2735    return _VSTD::minmax(__a, __b, __less<_Tp>());
2736}
2737
2738#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2739
2740template<class _Tp, class _Compare>
2741inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2742pair<_Tp, _Tp>
2743minmax(initializer_list<_Tp> __t, _Compare __comp)
2744{
2745    typedef typename initializer_list<_Tp>::const_iterator _Iter;
2746    _Iter __first = __t.begin();
2747    _Iter __last  = __t.end();
2748    std::pair<_Tp, _Tp> __result(*__first, *__first);
2749
2750    ++__first;
2751    if (__t.size() % 2 == 0)
2752    {
2753        if (__comp(*__first,  __result.first))
2754            __result.first  = *__first;
2755        else
2756            __result.second = *__first;
2757        ++__first;
2758    }
2759
2760    while (__first != __last)
2761    {
2762        _Tp __prev = *__first++;
2763        if (__comp(*__first, __prev)) {
2764            if ( __comp(*__first, __result.first)) __result.first  = *__first;
2765            if (!__comp(__prev, __result.second))  __result.second = __prev;
2766            }
2767        else {
2768            if ( __comp(__prev, __result.first))    __result.first  = __prev;
2769            if (!__comp(*__first, __result.second)) __result.second = *__first;
2770            }
2771
2772        __first++;
2773    }
2774    return __result;
2775}
2776
2777template<class _Tp>
2778inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
2779pair<_Tp, _Tp>
2780minmax(initializer_list<_Tp> __t)
2781{
2782    return _VSTD::minmax(__t, __less<_Tp>());
2783}
2784
2785#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
2786
2787// random_shuffle
2788
2789// __independent_bits_engine
2790
2791template <unsigned long long _Xp, size_t _Rp>
2792struct __log2_imp
2793{
2794    static const size_t value = _Xp & ((unsigned long long)(1) << _Rp) ? _Rp
2795                                           : __log2_imp<_Xp, _Rp - 1>::value;
2796};
2797
2798template <unsigned long long _Xp>
2799struct __log2_imp<_Xp, 0>
2800{
2801    static const size_t value = 0;
2802};
2803
2804template <size_t _Rp>
2805struct __log2_imp<0, _Rp>
2806{
2807    static const size_t value = _Rp + 1;
2808};
2809
2810template <class _UI, _UI _Xp>
2811struct __log2
2812{
2813    static const size_t value = __log2_imp<_Xp,
2814                                         sizeof(_UI) * __CHAR_BIT__ - 1>::value;
2815};
2816
2817template<class _Engine, class _UIntType>
2818class __independent_bits_engine
2819{
2820public:
2821    // types
2822    typedef _UIntType result_type;
2823
2824private:
2825    typedef typename _Engine::result_type _Engine_result_type;
2826    typedef typename conditional
2827        <
2828            sizeof(_Engine_result_type) <= sizeof(result_type),
2829                result_type,
2830                _Engine_result_type
2831        >::type _Working_result_type;
2832
2833    _Engine& __e_;
2834    size_t __w_;
2835    size_t __w0_;
2836    size_t __n_;
2837    size_t __n0_;
2838    _Working_result_type __y0_;
2839    _Working_result_type __y1_;
2840    _Engine_result_type __mask0_;
2841    _Engine_result_type __mask1_;
2842
2843#ifdef _LIBCPP_HAS_NO_CONSTEXPR
2844    static const _Working_result_type _Rp = _Engine::_Max - _Engine::_Min
2845                                          + _Working_result_type(1);
2846#else
2847    static _LIBCPP_CONSTEXPR const _Working_result_type _Rp = _Engine::max() - _Engine::min()
2848                                                      + _Working_result_type(1);
2849#endif
2850    static _LIBCPP_CONSTEXPR const size_t __m = __log2<_Working_result_type, _Rp>::value;
2851    static _LIBCPP_CONSTEXPR const size_t _WDt = numeric_limits<_Working_result_type>::digits;
2852    static _LIBCPP_CONSTEXPR const size_t _EDt = numeric_limits<_Engine_result_type>::digits;
2853
2854public:
2855    // constructors and seeding functions
2856    __independent_bits_engine(_Engine& __e, size_t __w);
2857
2858    // generating functions
2859    result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
2860
2861private:
2862    result_type __eval(false_type);
2863    result_type __eval(true_type);
2864};
2865
2866template<class _Engine, class _UIntType>
2867__independent_bits_engine<_Engine, _UIntType>
2868    ::__independent_bits_engine(_Engine& __e, size_t __w)
2869        : __e_(__e),
2870          __w_(__w)
2871{
2872    __n_ = __w_ / __m + (__w_ % __m != 0);
2873    __w0_ = __w_ / __n_;
2874    if (_Rp == 0)
2875        __y0_ = _Rp;
2876    else if (__w0_ < _WDt)
2877        __y0_ = (_Rp >> __w0_) << __w0_;
2878    else
2879        __y0_ = 0;
2880    if (_Rp - __y0_ > __y0_ / __n_)
2881    {
2882        ++__n_;
2883        __w0_ = __w_ / __n_;
2884        if (__w0_ < _WDt)
2885            __y0_ = (_Rp >> __w0_) << __w0_;
2886        else
2887            __y0_ = 0;
2888    }
2889    __n0_ = __n_ - __w_ % __n_;
2890    if (__w0_ < _WDt - 1)
2891        __y1_ = (_Rp >> (__w0_ + 1)) << (__w0_ + 1);
2892    else
2893        __y1_ = 0;
2894    __mask0_ = __w0_ > 0 ? _Engine_result_type(~0) >> (_EDt - __w0_) :
2895                          _Engine_result_type(0);
2896    __mask1_ = __w0_ < _EDt - 1 ?
2897                               _Engine_result_type(~0) >> (_EDt - (__w0_ + 1)) :
2898                               _Engine_result_type(~0);
2899}
2900
2901template<class _Engine, class _UIntType>
2902inline
2903_UIntType
2904__independent_bits_engine<_Engine, _UIntType>::__eval(false_type)
2905{
2906    return static_cast<result_type>(__e_() & __mask0_);
2907}
2908
2909template<class _Engine, class _UIntType>
2910_UIntType
2911__independent_bits_engine<_Engine, _UIntType>::__eval(true_type)
2912{
2913    result_type _Sp = 0;
2914    for (size_t __k = 0; __k < __n0_; ++__k)
2915    {
2916        _Engine_result_type __u;
2917        do
2918        {
2919            __u = __e_() - _Engine::min();
2920        } while (__u >= __y0_);
2921        if (__w0_ < _WDt)
2922            _Sp <<= __w0_;
2923        else
2924            _Sp = 0;
2925        _Sp += __u & __mask0_;
2926    }
2927    for (size_t __k = __n0_; __k < __n_; ++__k)
2928    {
2929        _Engine_result_type __u;
2930        do
2931        {
2932            __u = __e_() - _Engine::min();
2933        } while (__u >= __y1_);
2934        if (__w0_ < _WDt - 1)
2935            _Sp <<= __w0_ + 1;
2936        else
2937            _Sp = 0;
2938        _Sp += __u & __mask1_;
2939    }
2940    return _Sp;
2941}
2942
2943// uniform_int_distribution
2944
2945template<class _IntType = int>
2946class uniform_int_distribution
2947{
2948public:
2949    // types
2950    typedef _IntType result_type;
2951
2952    class param_type
2953    {
2954        result_type __a_;
2955        result_type __b_;
2956    public:
2957        typedef uniform_int_distribution distribution_type;
2958
2959        explicit param_type(result_type __a = 0,
2960                            result_type __b = numeric_limits<result_type>::max())
2961            : __a_(__a), __b_(__b) {}
2962
2963        result_type a() const {return __a_;}
2964        result_type b() const {return __b_;}
2965
2966        friend bool operator==(const param_type& __x, const param_type& __y)
2967            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
2968        friend bool operator!=(const param_type& __x, const param_type& __y)
2969            {return !(__x == __y);}
2970    };
2971
2972private:
2973    param_type __p_;
2974
2975public:
2976    // constructors and reset functions
2977    explicit uniform_int_distribution(result_type __a = 0,
2978                                      result_type __b = numeric_limits<result_type>::max())
2979        : __p_(param_type(__a, __b)) {}
2980    explicit uniform_int_distribution(const param_type& __p) : __p_(__p) {}
2981    void reset() {}
2982
2983    // generating functions
2984    template<class _URNG> result_type operator()(_URNG& __g)
2985        {return (*this)(__g, __p_);}
2986    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
2987
2988    // property functions
2989    result_type a() const {return __p_.a();}
2990    result_type b() const {return __p_.b();}
2991
2992    param_type param() const {return __p_;}
2993    void param(const param_type& __p) {__p_ = __p;}
2994
2995    result_type min() const {return a();}
2996    result_type max() const {return b();}
2997
2998    friend bool operator==(const uniform_int_distribution& __x,
2999                           const uniform_int_distribution& __y)
3000        {return __x.__p_ == __y.__p_;}
3001    friend bool operator!=(const uniform_int_distribution& __x,
3002                           const uniform_int_distribution& __y)
3003            {return !(__x == __y);}
3004};
3005
3006template<class _IntType>
3007template<class _URNG>
3008typename uniform_int_distribution<_IntType>::result_type
3009uniform_int_distribution<_IntType>::operator()(_URNG& __g, const param_type& __p)
3010{
3011    typedef typename conditional<sizeof(result_type) <= sizeof(uint32_t),
3012                                            uint32_t, uint64_t>::type _UIntType;
3013    const _UIntType _Rp = __p.b() - __p.a() + _UIntType(1);
3014    if (_Rp == 1)
3015        return __p.a();
3016    const size_t _Dt = numeric_limits<_UIntType>::digits;
3017    typedef __independent_bits_engine<_URNG, _UIntType> _Eng;
3018    if (_Rp == 0)
3019        return static_cast<result_type>(_Eng(__g, _Dt)());
3020    size_t __w = _Dt - __clz(_Rp) - 1;
3021    if ((_Rp & (std::numeric_limits<_UIntType>::max() >> (_Dt - __w))) != 0)
3022        ++__w;
3023    _Eng __e(__g, __w);
3024    _UIntType __u;
3025    do
3026    {
3027        __u = __e();
3028    } while (__u >= _Rp);
3029    return static_cast<result_type>(__u + __p.a());
3030}
3031
3032class _LIBCPP_TYPE_VIS __rs_default;
3033
3034_LIBCPP_FUNC_VIS __rs_default __rs_get();
3035
3036class _LIBCPP_TYPE_VIS __rs_default
3037{
3038    static unsigned __c_;
3039
3040    __rs_default();
3041public:
3042    typedef uint_fast32_t result_type;
3043
3044    static const result_type _Min = 0;
3045    static const result_type _Max = 0xFFFFFFFF;
3046
3047    __rs_default(const __rs_default&);
3048    ~__rs_default();
3049
3050    result_type operator()();
3051
3052    static _LIBCPP_CONSTEXPR result_type min() {return _Min;}
3053    static _LIBCPP_CONSTEXPR result_type max() {return _Max;}
3054
3055    friend _LIBCPP_FUNC_VIS __rs_default __rs_get();
3056};
3057
3058_LIBCPP_FUNC_VIS __rs_default __rs_get();
3059
3060template <class _RandomAccessIterator>
3061void
3062random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)
3063{
3064    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3065    typedef uniform_int_distribution<ptrdiff_t> _Dp;
3066    typedef typename _Dp::param_type _Pp;
3067    difference_type __d = __last - __first;
3068    if (__d > 1)
3069    {
3070        _Dp __uid;
3071        __rs_default __g = __rs_get();
3072        for (--__last, --__d; __first < __last; ++__first, --__d)
3073        {
3074            difference_type __i = __uid(__g, _Pp(0, __d));
3075            if (__i != difference_type(0))
3076                swap(*__first, *(__first + __i));
3077        }
3078    }
3079}
3080
3081template <class _RandomAccessIterator, class _RandomNumberGenerator>
3082void
3083random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
3084#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3085               _RandomNumberGenerator&& __rand)
3086#else
3087               _RandomNumberGenerator& __rand)
3088#endif
3089{
3090    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3091    difference_type __d = __last - __first;
3092    if (__d > 1)
3093    {
3094        for (--__last; __first < __last; ++__first, --__d)
3095        {
3096            difference_type __i = __rand(__d);
3097            swap(*__first, *(__first + __i));
3098        }
3099    }
3100}
3101
3102template<class _RandomAccessIterator, class _UniformRandomNumberGenerator>
3103    void shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
3104#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
3105                 _UniformRandomNumberGenerator&& __g)
3106#else
3107                 _UniformRandomNumberGenerator& __g)
3108#endif
3109{
3110    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3111    typedef uniform_int_distribution<ptrdiff_t> _Dp;
3112    typedef typename _Dp::param_type _Pp;
3113    difference_type __d = __last - __first;
3114    if (__d > 1)
3115    {
3116        _Dp __uid;
3117        for (--__last, --__d; __first < __last; ++__first, --__d)
3118        {
3119            difference_type __i = __uid(__g, _Pp(0, __d));
3120            if (__i != difference_type(0))
3121                swap(*__first, *(__first + __i));
3122        }
3123    }
3124}
3125
3126template <class _InputIterator, class _Predicate>
3127bool
3128is_partitioned(_InputIterator __first, _InputIterator __last, _Predicate __pred)
3129{
3130    for (; __first != __last; ++__first)
3131        if (!__pred(*__first))
3132            break;
3133    if ( __first == __last )
3134        return true;
3135    ++__first;
3136    for (; __first != __last; ++__first)
3137        if (__pred(*__first))
3138            return false;
3139    return true;
3140}
3141
3142// partition
3143
3144template <class _Predicate, class _ForwardIterator>
3145_ForwardIterator
3146__partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, forward_iterator_tag)
3147{
3148    while (true)
3149    {
3150        if (__first == __last)
3151            return __first;
3152        if (!__pred(*__first))
3153            break;
3154        ++__first;
3155    }
3156    for (_ForwardIterator __p = __first; ++__p != __last;)
3157    {
3158        if (__pred(*__p))
3159        {
3160            swap(*__first, *__p);
3161            ++__first;
3162        }
3163    }
3164    return __first;
3165}
3166
3167template <class _Predicate, class _BidirectionalIterator>
3168_BidirectionalIterator
3169__partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
3170            bidirectional_iterator_tag)
3171{
3172    while (true)
3173    {
3174        while (true)
3175        {
3176            if (__first == __last)
3177                return __first;
3178            if (!__pred(*__first))
3179                break;
3180            ++__first;
3181        }
3182        do
3183        {
3184            if (__first == --__last)
3185                return __first;
3186        } while (!__pred(*__last));
3187        swap(*__first, *__last);
3188        ++__first;
3189    }
3190}
3191
3192template <class _ForwardIterator, class _Predicate>
3193inline _LIBCPP_INLINE_VISIBILITY
3194_ForwardIterator
3195partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
3196{
3197    return _VSTD::__partition<typename add_lvalue_reference<_Predicate>::type>
3198                            (__first, __last, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
3199}
3200
3201// partition_copy
3202
3203template <class _InputIterator, class _OutputIterator1,
3204          class _OutputIterator2, class _Predicate>
3205pair<_OutputIterator1, _OutputIterator2>
3206partition_copy(_InputIterator __first, _InputIterator __last,
3207               _OutputIterator1 __out_true, _OutputIterator2 __out_false,
3208               _Predicate __pred)
3209{
3210    for (; __first != __last; ++__first)
3211    {
3212        if (__pred(*__first))
3213        {
3214            *__out_true = *__first;
3215            ++__out_true;
3216        }
3217        else
3218        {
3219            *__out_false = *__first;
3220            ++__out_false;
3221        }
3222    }
3223    return pair<_OutputIterator1, _OutputIterator2>(__out_true, __out_false);
3224}
3225
3226// partition_point
3227
3228template<class _ForwardIterator, class _Predicate>
3229_ForwardIterator
3230partition_point(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
3231{
3232    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
3233    difference_type __len = _VSTD::distance(__first, __last);
3234    while (__len != 0)
3235    {
3236        difference_type __l2 = __len / 2;
3237        _ForwardIterator __m = __first;
3238        _VSTD::advance(__m, __l2);
3239        if (__pred(*__m))
3240        {
3241            __first = ++__m;
3242            __len -= __l2 + 1;
3243        }
3244        else
3245            __len = __l2;
3246    }
3247    return __first;
3248}
3249
3250// stable_partition
3251
3252template <class _Predicate, class _ForwardIterator, class _Distance, class _Pair>
3253_ForwardIterator
3254__stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred,
3255                   _Distance __len, _Pair __p, forward_iterator_tag __fit)
3256{
3257    // *__first is known to be false
3258    // __len >= 1
3259    if (__len == 1)
3260        return __first;
3261    if (__len == 2)
3262    {
3263        _ForwardIterator __m = __first;
3264        if (__pred(*++__m))
3265        {
3266            swap(*__first, *__m);
3267            return __m;
3268        }
3269        return __first;
3270    }
3271    if (__len <= __p.second)
3272    {   // The buffer is big enough to use
3273        typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
3274        __destruct_n __d(0);
3275        unique_ptr<value_type, __destruct_n&> __h(__p.first, __d);
3276        // Move the falses into the temporary buffer, and the trues to the front of the line
3277        // Update __first to always point to the end of the trues
3278        value_type* __t = __p.first;
3279        ::new(__t) value_type(_VSTD::move(*__first));
3280        __d.__incr((value_type*)0);
3281        ++__t;
3282        _ForwardIterator __i = __first;
3283        while (++__i != __last)
3284        {
3285            if (__pred(*__i))
3286            {
3287                *__first = _VSTD::move(*__i);
3288                ++__first;
3289            }
3290            else
3291            {
3292                ::new(__t) value_type(_VSTD::move(*__i));
3293                __d.__incr((value_type*)0);
3294                ++__t;
3295            }
3296        }
3297        // All trues now at start of range, all falses in buffer
3298        // Move falses back into range, but don't mess up __first which points to first false
3299        __i = __first;
3300        for (value_type* __t2 = __p.first; __t2 < __t; ++__t2, ++__i)
3301            *__i = _VSTD::move(*__t2);
3302        // __h destructs moved-from values out of the temp buffer, but doesn't deallocate buffer
3303        return __first;
3304    }
3305    // Else not enough buffer, do in place
3306    // __len >= 3
3307    _ForwardIterator __m = __first;
3308    _Distance __len2 = __len / 2;  // __len2 >= 2
3309    _VSTD::advance(__m, __len2);
3310    // recurse on [__first, __m), *__first know to be false
3311    // F?????????????????
3312    // f       m         l
3313    typedef typename add_lvalue_reference<_Predicate>::type _PredRef;
3314    _ForwardIterator __first_false = __stable_partition<_PredRef>(__first, __m, __pred, __len2, __p, __fit);
3315    // TTTFFFFF??????????
3316    // f  ff   m         l
3317    // recurse on [__m, __last], except increase __m until *(__m) is false, *__last know to be true
3318    _ForwardIterator __m1 = __m;
3319    _ForwardIterator __second_false = __last;
3320    _Distance __len_half = __len - __len2;
3321    while (__pred(*__m1))
3322    {
3323        if (++__m1 == __last)
3324            goto __second_half_done;
3325        --__len_half;
3326    }
3327    // TTTFFFFFTTTF??????
3328    // f  ff   m  m1     l
3329    __second_false = __stable_partition<_PredRef>(__m1, __last, __pred, __len_half, __p, __fit);
3330__second_half_done:
3331    // TTTFFFFFTTTTTFFFFF
3332    // f  ff   m    sf   l
3333    return _VSTD::rotate(__first_false, __m, __second_false);
3334    // TTTTTTTTFFFFFFFFFF
3335    //         |
3336}
3337
3338struct __return_temporary_buffer
3339{
3340    template <class _Tp>
3341    _LIBCPP_INLINE_VISIBILITY void operator()(_Tp* __p) const {_VSTD::return_temporary_buffer(__p);}
3342};
3343
3344template <class _Predicate, class _ForwardIterator>
3345_ForwardIterator
3346__stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred,
3347                   forward_iterator_tag)
3348{
3349    const unsigned __alloc_limit = 3;  // might want to make this a function of trivial assignment
3350    // Either prove all true and return __first or point to first false
3351    while (true)
3352    {
3353        if (__first == __last)
3354            return __first;
3355        if (!__pred(*__first))
3356            break;
3357        ++__first;
3358    }
3359    // We now have a reduced range [__first, __last)
3360    // *__first is known to be false
3361    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
3362    typedef typename iterator_traits<_ForwardIterator>::value_type value_type;
3363    difference_type __len = _VSTD::distance(__first, __last);
3364    pair<value_type*, ptrdiff_t> __p(0, 0);
3365    unique_ptr<value_type, __return_temporary_buffer> __h;
3366    if (__len >= __alloc_limit)
3367    {
3368        __p = _VSTD::get_temporary_buffer<value_type>(__len);
3369        __h.reset(__p.first);
3370    }
3371    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
3372                             (__first, __last, __pred, __len, __p, forward_iterator_tag());
3373}
3374
3375template <class _Predicate, class _BidirectionalIterator, class _Distance, class _Pair>
3376_BidirectionalIterator
3377__stable_partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
3378                   _Distance __len, _Pair __p, bidirectional_iterator_tag __bit)
3379{
3380    // *__first is known to be false
3381    // *__last is known to be true
3382    // __len >= 2
3383    if (__len == 2)
3384    {
3385        swap(*__first, *__last);
3386        return __last;
3387    }
3388    if (__len == 3)
3389    {
3390        _BidirectionalIterator __m = __first;
3391        if (__pred(*++__m))
3392        {
3393            swap(*__first, *__m);
3394            swap(*__m, *__last);
3395            return __last;
3396        }
3397        swap(*__m, *__last);
3398        swap(*__first, *__m);
3399        return __m;
3400    }
3401    if (__len <= __p.second)
3402    {   // The buffer is big enough to use
3403        typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
3404        __destruct_n __d(0);
3405        unique_ptr<value_type, __destruct_n&> __h(__p.first, __d);
3406        // Move the falses into the temporary buffer, and the trues to the front of the line
3407        // Update __first to always point to the end of the trues
3408        value_type* __t = __p.first;
3409        ::new(__t) value_type(_VSTD::move(*__first));
3410        __d.__incr((value_type*)0);
3411        ++__t;
3412        _BidirectionalIterator __i = __first;
3413        while (++__i != __last)
3414        {
3415            if (__pred(*__i))
3416            {
3417                *__first = _VSTD::move(*__i);
3418                ++__first;
3419            }
3420            else
3421            {
3422                ::new(__t) value_type(_VSTD::move(*__i));
3423                __d.__incr((value_type*)0);
3424                ++__t;
3425            }
3426        }
3427        // move *__last, known to be true
3428        *__first = _VSTD::move(*__i);
3429        __i = ++__first;
3430        // All trues now at start of range, all falses in buffer
3431        // Move falses back into range, but don't mess up __first which points to first false
3432        for (value_type* __t2 = __p.first; __t2 < __t; ++__t2, ++__i)
3433            *__i = _VSTD::move(*__t2);
3434        // __h destructs moved-from values out of the temp buffer, but doesn't deallocate buffer
3435        return __first;
3436    }
3437    // Else not enough buffer, do in place
3438    // __len >= 4
3439    _BidirectionalIterator __m = __first;
3440    _Distance __len2 = __len / 2;  // __len2 >= 2
3441    _VSTD::advance(__m, __len2);
3442    // recurse on [__first, __m-1], except reduce __m-1 until *(__m-1) is true, *__first know to be false
3443    // F????????????????T
3444    // f       m        l
3445    _BidirectionalIterator __m1 = __m;
3446    _BidirectionalIterator __first_false = __first;
3447    _Distance __len_half = __len2;
3448    while (!__pred(*--__m1))
3449    {
3450        if (__m1 == __first)
3451            goto __first_half_done;
3452        --__len_half;
3453    }
3454    // F???TFFF?????????T
3455    // f   m1  m        l
3456    typedef typename add_lvalue_reference<_Predicate>::type _PredRef;
3457    __first_false = __stable_partition<_PredRef>(__first, __m1, __pred, __len_half, __p, __bit);
3458__first_half_done:
3459    // TTTFFFFF?????????T
3460    // f  ff   m        l
3461    // recurse on [__m, __last], except increase __m until *(__m) is false, *__last know to be true
3462    __m1 = __m;
3463    _BidirectionalIterator __second_false = __last;
3464    ++__second_false;
3465    __len_half = __len - __len2;
3466    while (__pred(*__m1))
3467    {
3468        if (++__m1 == __last)
3469            goto __second_half_done;
3470        --__len_half;
3471    }
3472    // TTTFFFFFTTTF?????T
3473    // f  ff   m  m1    l
3474    __second_false = __stable_partition<_PredRef>(__m1, __last, __pred, __len_half, __p, __bit);
3475__second_half_done:
3476    // TTTFFFFFTTTTTFFFFF
3477    // f  ff   m    sf  l
3478    return _VSTD::rotate(__first_false, __m, __second_false);
3479    // TTTTTTTTFFFFFFFFFF
3480    //         |
3481}
3482
3483template <class _Predicate, class _BidirectionalIterator>
3484_BidirectionalIterator
3485__stable_partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
3486                   bidirectional_iterator_tag)
3487{
3488    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
3489    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
3490    const difference_type __alloc_limit = 4;  // might want to make this a function of trivial assignment
3491    // Either prove all true and return __first or point to first false
3492    while (true)
3493    {
3494        if (__first == __last)
3495            return __first;
3496        if (!__pred(*__first))
3497            break;
3498        ++__first;
3499    }
3500    // __first points to first false, everything prior to __first is already set.
3501    // Either prove [__first, __last) is all false and return __first, or point __last to last true
3502    do
3503    {
3504        if (__first == --__last)
3505            return __first;
3506    } while (!__pred(*__last));
3507    // We now have a reduced range [__first, __last]
3508    // *__first is known to be false
3509    // *__last is known to be true
3510    // __len >= 2
3511    difference_type __len = _VSTD::distance(__first, __last) + 1;
3512    pair<value_type*, ptrdiff_t> __p(0, 0);
3513    unique_ptr<value_type, __return_temporary_buffer> __h;
3514    if (__len >= __alloc_limit)
3515    {
3516        __p = _VSTD::get_temporary_buffer<value_type>(__len);
3517        __h.reset(__p.first);
3518    }
3519    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
3520                             (__first, __last, __pred, __len, __p, bidirectional_iterator_tag());
3521}
3522
3523template <class _ForwardIterator, class _Predicate>
3524inline _LIBCPP_INLINE_VISIBILITY
3525_ForwardIterator
3526stable_partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
3527{
3528    return __stable_partition<typename add_lvalue_reference<_Predicate>::type>
3529                             (__first, __last, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
3530}
3531
3532// is_sorted_until
3533
3534template <class _ForwardIterator, class _Compare>
3535_ForwardIterator
3536is_sorted_until(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
3537{
3538    if (__first != __last)
3539    {
3540        _ForwardIterator __i = __first;
3541        while (++__i != __last)
3542        {
3543            if (__comp(*__i, *__first))
3544                return __i;
3545            __first = __i;
3546        }
3547    }
3548    return __last;
3549}
3550
3551template<class _ForwardIterator>
3552inline _LIBCPP_INLINE_VISIBILITY
3553_ForwardIterator
3554is_sorted_until(_ForwardIterator __first, _ForwardIterator __last)
3555{
3556    return _VSTD::is_sorted_until(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
3557}
3558
3559// is_sorted
3560
3561template <class _ForwardIterator, class _Compare>
3562inline _LIBCPP_INLINE_VISIBILITY
3563bool
3564is_sorted(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp)
3565{
3566    return _VSTD::is_sorted_until(__first, __last, __comp) == __last;
3567}
3568
3569template<class _ForwardIterator>
3570inline _LIBCPP_INLINE_VISIBILITY
3571bool
3572is_sorted(_ForwardIterator __first, _ForwardIterator __last)
3573{
3574    return _VSTD::is_sorted(__first, __last, __less<typename iterator_traits<_ForwardIterator>::value_type>());
3575}
3576
3577// sort
3578
3579// stable, 2-3 compares, 0-2 swaps
3580
3581template <class _Compare, class _ForwardIterator>
3582unsigned
3583__sort3(_ForwardIterator __x, _ForwardIterator __y, _ForwardIterator __z, _Compare __c)
3584{
3585    unsigned __r = 0;
3586    if (!__c(*__y, *__x))          // if x <= y
3587    {
3588        if (!__c(*__z, *__y))      // if y <= z
3589            return __r;            // x <= y && y <= z
3590                                   // x <= y && y > z
3591        swap(*__y, *__z);          // x <= z && y < z
3592        __r = 1;
3593        if (__c(*__y, *__x))       // if x > y
3594        {
3595            swap(*__x, *__y);      // x < y && y <= z
3596            __r = 2;
3597        }
3598        return __r;                // x <= y && y < z
3599    }
3600    if (__c(*__z, *__y))           // x > y, if y > z
3601    {
3602        swap(*__x, *__z);          // x < y && y < z
3603        __r = 1;
3604        return __r;
3605    }
3606    swap(*__x, *__y);              // x > y && y <= z
3607    __r = 1;                       // x < y && x <= z
3608    if (__c(*__z, *__y))           // if y > z
3609    {
3610        swap(*__y, *__z);          // x <= y && y < z
3611        __r = 2;
3612    }
3613    return __r;
3614}                                  // x <= y && y <= z
3615
3616// stable, 3-6 compares, 0-5 swaps
3617
3618template <class _Compare, class _ForwardIterator>
3619unsigned
3620__sort4(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3,
3621            _ForwardIterator __x4, _Compare __c)
3622{
3623    unsigned __r = __sort3<_Compare>(__x1, __x2, __x3, __c);
3624    if (__c(*__x4, *__x3))
3625    {
3626        swap(*__x3, *__x4);
3627        ++__r;
3628        if (__c(*__x3, *__x2))
3629        {
3630            swap(*__x2, *__x3);
3631            ++__r;
3632            if (__c(*__x2, *__x1))
3633            {
3634                swap(*__x1, *__x2);
3635                ++__r;
3636            }
3637        }
3638    }
3639    return __r;
3640}
3641
3642// stable, 4-10 compares, 0-9 swaps
3643
3644template <class _Compare, class _ForwardIterator>
3645unsigned
3646__sort5(_ForwardIterator __x1, _ForwardIterator __x2, _ForwardIterator __x3,
3647            _ForwardIterator __x4, _ForwardIterator __x5, _Compare __c)
3648{
3649    unsigned __r = __sort4<_Compare>(__x1, __x2, __x3, __x4, __c);
3650    if (__c(*__x5, *__x4))
3651    {
3652        swap(*__x4, *__x5);
3653        ++__r;
3654        if (__c(*__x4, *__x3))
3655        {
3656            swap(*__x3, *__x4);
3657            ++__r;
3658            if (__c(*__x3, *__x2))
3659            {
3660                swap(*__x2, *__x3);
3661                ++__r;
3662                if (__c(*__x2, *__x1))
3663                {
3664                    swap(*__x1, *__x2);
3665                    ++__r;
3666                }
3667            }
3668        }
3669    }
3670    return __r;
3671}
3672
3673// Assumes size > 0
3674template <class _Compare, class _BirdirectionalIterator>
3675void
3676__selection_sort(_BirdirectionalIterator __first, _BirdirectionalIterator __last, _Compare __comp)
3677{
3678    _BirdirectionalIterator __lm1 = __last;
3679    for (--__lm1; __first != __lm1; ++__first)
3680    {
3681        _BirdirectionalIterator __i = _VSTD::min_element<_BirdirectionalIterator,
3682                                                        typename add_lvalue_reference<_Compare>::type>
3683                                                       (__first, __last, __comp);
3684        if (__i != __first)
3685            swap(*__first, *__i);
3686    }
3687}
3688
3689template <class _Compare, class _BirdirectionalIterator>
3690void
3691__insertion_sort(_BirdirectionalIterator __first, _BirdirectionalIterator __last, _Compare __comp)
3692{
3693    typedef typename iterator_traits<_BirdirectionalIterator>::value_type value_type;
3694    if (__first != __last)
3695    {
3696        _BirdirectionalIterator __i = __first;
3697        for (++__i; __i != __last; ++__i)
3698        {
3699            _BirdirectionalIterator __j = __i;
3700            value_type __t(_VSTD::move(*__j));
3701            for (_BirdirectionalIterator __k = __i; __k != __first && __comp(__t,  *--__k); --__j)
3702                *__j = _VSTD::move(*__k);
3703            *__j = _VSTD::move(__t);
3704        }
3705    }
3706}
3707
3708template <class _Compare, class _RandomAccessIterator>
3709void
3710__insertion_sort_3(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
3711{
3712    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
3713    _RandomAccessIterator __j = __first+2;
3714    __sort3<_Compare>(__first, __first+1, __j, __comp);
3715    for (_RandomAccessIterator __i = __j+1; __i != __last; ++__i)
3716    {
3717        if (__comp(*__i, *__j))
3718        {
3719            value_type __t(_VSTD::move(*__i));
3720            _RandomAccessIterator __k = __j;
3721            __j = __i;
3722            do
3723            {
3724                *__j = _VSTD::move(*__k);
3725                __j = __k;
3726            } while (__j != __first && __comp(__t, *--__k));
3727            *__j = _VSTD::move(__t);
3728        }
3729        __j = __i;
3730    }
3731}
3732
3733template <class _Compare, class _RandomAccessIterator>
3734bool
3735__insertion_sort_incomplete(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
3736{
3737    switch (__last - __first)
3738    {
3739    case 0:
3740    case 1:
3741        return true;
3742    case 2:
3743        if (__comp(*--__last, *__first))
3744            swap(*__first, *__last);
3745        return true;
3746    case 3:
3747        _VSTD::__sort3<_Compare>(__first, __first+1, --__last, __comp);
3748        return true;
3749    case 4:
3750        _VSTD::__sort4<_Compare>(__first, __first+1, __first+2, --__last, __comp);
3751        return true;
3752    case 5:
3753        _VSTD::__sort5<_Compare>(__first, __first+1, __first+2, __first+3, --__last, __comp);
3754        return true;
3755    }
3756    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
3757    _RandomAccessIterator __j = __first+2;
3758    __sort3<_Compare>(__first, __first+1, __j, __comp);
3759    const unsigned __limit = 8;
3760    unsigned __count = 0;
3761    for (_RandomAccessIterator __i = __j+1; __i != __last; ++__i)
3762    {
3763        if (__comp(*__i, *__j))
3764        {
3765            value_type __t(_VSTD::move(*__i));
3766            _RandomAccessIterator __k = __j;
3767            __j = __i;
3768            do
3769            {
3770                *__j = _VSTD::move(*__k);
3771                __j = __k;
3772            } while (__j != __first && __comp(__t, *--__k));
3773            *__j = _VSTD::move(__t);
3774            if (++__count == __limit)
3775                return ++__i == __last;
3776        }
3777        __j = __i;
3778    }
3779    return true;
3780}
3781
3782template <class _Compare, class _BirdirectionalIterator>
3783void
3784__insertion_sort_move(_BirdirectionalIterator __first1, _BirdirectionalIterator __last1,
3785                      typename iterator_traits<_BirdirectionalIterator>::value_type* __first2, _Compare __comp)
3786{
3787    typedef typename iterator_traits<_BirdirectionalIterator>::value_type value_type;
3788    if (__first1 != __last1)
3789    {
3790        __destruct_n __d(0);
3791        unique_ptr<value_type, __destruct_n&> __h(__first2, __d);
3792        value_type* __last2 = __first2;
3793        ::new(__last2) value_type(_VSTD::move(*__first1));
3794        __d.__incr((value_type*)0);
3795        for (++__last2; ++__first1 != __last1; ++__last2)
3796        {
3797            value_type* __j2 = __last2;
3798            value_type* __i2 = __j2;
3799            if (__comp(*__first1, *--__i2))
3800            {
3801                ::new(__j2) value_type(_VSTD::move(*__i2));
3802                __d.__incr((value_type*)0);
3803                for (--__j2; __i2 != __first2 && __comp(*__first1,  *--__i2); --__j2)
3804                    *__j2 = _VSTD::move(*__i2);
3805                *__j2 = _VSTD::move(*__first1);
3806            }
3807            else
3808            {
3809                ::new(__j2) value_type(_VSTD::move(*__first1));
3810                __d.__incr((value_type*)0);
3811            }
3812        }
3813        __h.release();
3814    }
3815}
3816
3817template <class _Compare, class _RandomAccessIterator>
3818void
3819__sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
3820{
3821    // _Compare is known to be a reference type
3822    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
3823    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
3824    const difference_type __limit = is_trivially_copy_constructible<value_type>::value &&
3825                                    is_trivially_copy_assignable<value_type>::value ? 30 : 6;
3826    while (true)
3827    {
3828    __restart:
3829        difference_type __len = __last - __first;
3830        switch (__len)
3831        {
3832        case 0:
3833        case 1:
3834            return;
3835        case 2:
3836            if (__comp(*--__last, *__first))
3837                swap(*__first, *__last);
3838            return;
3839        case 3:
3840            _VSTD::__sort3<_Compare>(__first, __first+1, --__last, __comp);
3841            return;
3842        case 4:
3843            _VSTD::__sort4<_Compare>(__first, __first+1, __first+2, --__last, __comp);
3844            return;
3845        case 5:
3846            _VSTD::__sort5<_Compare>(__first, __first+1, __first+2, __first+3, --__last, __comp);
3847            return;
3848        }
3849        if (__len <= __limit)
3850        {
3851            _VSTD::__insertion_sort_3<_Compare>(__first, __last, __comp);
3852            return;
3853        }
3854        // __len > 5
3855        _RandomAccessIterator __m = __first;
3856        _RandomAccessIterator __lm1 = __last;
3857        --__lm1;
3858        unsigned __n_swaps;
3859        {
3860        difference_type __delta;
3861        if (__len >= 1000)
3862        {
3863            __delta = __len/2;
3864            __m += __delta;
3865            __delta /= 2;
3866            __n_swaps = _VSTD::__sort5<_Compare>(__first, __first + __delta, __m, __m+__delta, __lm1, __comp);
3867        }
3868        else
3869        {
3870            __delta = __len/2;
3871            __m += __delta;
3872            __n_swaps = _VSTD::__sort3<_Compare>(__first, __m, __lm1, __comp);
3873        }
3874        }
3875        // *__m is median
3876        // partition [__first, __m) < *__m and *__m <= [__m, __last)
3877        // (this inhibits tossing elements equivalent to __m around unnecessarily)
3878        _RandomAccessIterator __i = __first;
3879        _RandomAccessIterator __j = __lm1;
3880        // j points beyond range to be tested, *__m is known to be <= *__lm1
3881        // The search going up is known to be guarded but the search coming down isn't.
3882        // Prime the downward search with a guard.
3883        if (!__comp(*__i, *__m))  // if *__first == *__m
3884        {
3885            // *__first == *__m, *__first doesn't go in first part
3886            // manually guard downward moving __j against __i
3887            while (true)
3888            {
3889                if (__i == --__j)
3890                {
3891                    // *__first == *__m, *__m <= all other elements
3892                    // Parition instead into [__first, __i) == *__first and *__first < [__i, __last)
3893                    ++__i;  // __first + 1
3894                    __j = __last;
3895                    if (!__comp(*__first, *--__j))  // we need a guard if *__first == *(__last-1)
3896                    {
3897                        while (true)
3898                        {
3899                            if (__i == __j)
3900                                return;  // [__first, __last) all equivalent elements
3901                            if (__comp(*__first, *__i))
3902                            {
3903                                swap(*__i, *__j);
3904                                ++__n_swaps;
3905                                ++__i;
3906                                break;
3907                            }
3908                            ++__i;
3909                        }
3910                    }
3911                    // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
3912                    if (__i == __j)
3913                        return;
3914                    while (true)
3915                    {
3916                        while (!__comp(*__first, *__i))
3917                            ++__i;
3918                        while (__comp(*__first, *--__j))
3919                            ;
3920                        if (__i >= __j)
3921                            break;
3922                        swap(*__i, *__j);
3923                        ++__n_swaps;
3924                        ++__i;
3925                    }
3926                    // [__first, __i) == *__first and *__first < [__i, __last)
3927                    // The first part is sorted, sort the secod part
3928                    // _VSTD::__sort<_Compare>(__i, __last, __comp);
3929                    __first = __i;
3930                    goto __restart;
3931                }
3932                if (__comp(*__j, *__m))
3933                {
3934                    swap(*__i, *__j);
3935                    ++__n_swaps;
3936                    break;  // found guard for downward moving __j, now use unguarded partition
3937                }
3938            }
3939        }
3940        // It is known that *__i < *__m
3941        ++__i;
3942        // j points beyond range to be tested, *__m is known to be <= *__lm1
3943        // if not yet partitioned...
3944        if (__i < __j)
3945        {
3946            // known that *(__i - 1) < *__m
3947            // known that __i <= __m
3948            while (true)
3949            {
3950                // __m still guards upward moving __i
3951                while (__comp(*__i, *__m))
3952                    ++__i;
3953                // It is now known that a guard exists for downward moving __j
3954                while (!__comp(*--__j, *__m))
3955                    ;
3956                if (__i > __j)
3957                    break;
3958                swap(*__i, *__j);
3959                ++__n_swaps;
3960                // It is known that __m != __j
3961                // If __m just moved, follow it
3962                if (__m == __i)
3963                    __m = __j;
3964                ++__i;
3965            }
3966        }
3967        // [__first, __i) < *__m and *__m <= [__i, __last)
3968        if (__i != __m && __comp(*__m, *__i))
3969        {
3970            swap(*__i, *__m);
3971            ++__n_swaps;
3972        }
3973        // [__first, __i) < *__i and *__i <= [__i+1, __last)
3974        // If we were given a perfect partition, see if insertion sort is quick...
3975        if (__n_swaps == 0)
3976        {
3977            bool __fs = _VSTD::__insertion_sort_incomplete<_Compare>(__first, __i, __comp);
3978            if (_VSTD::__insertion_sort_incomplete<_Compare>(__i+1, __last, __comp))
3979            {
3980                if (__fs)
3981                    return;
3982                __last = __i;
3983                continue;
3984            }
3985            else
3986            {
3987                if (__fs)
3988                {
3989                    __first = ++__i;
3990                    continue;
3991                }
3992            }
3993        }
3994        // sort smaller range with recursive call and larger with tail recursion elimination
3995        if (__i - __first < __last - __i)
3996        {
3997            _VSTD::__sort<_Compare>(__first, __i, __comp);
3998            // _VSTD::__sort<_Compare>(__i+1, __last, __comp);
3999            __first = ++__i;
4000        }
4001        else
4002        {
4003            _VSTD::__sort<_Compare>(__i+1, __last, __comp);
4004            // _VSTD::__sort<_Compare>(__first, __i, __comp);
4005            __last = __i;
4006        }
4007    }
4008}
4009
4010// This forwarder keeps the top call and the recursive calls using the same instantiation, forcing a reference _Compare
4011template <class _RandomAccessIterator, class _Compare>
4012inline _LIBCPP_INLINE_VISIBILITY
4013void
4014sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4015{
4016#ifdef _LIBCPP_DEBUG
4017    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4018    __debug_less<_Compare> __c(__comp);
4019    __sort<_Comp_ref>(__first, __last, __c);
4020#else  // _LIBCPP_DEBUG
4021    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4022    __sort<_Comp_ref>(__first, __last, __comp);
4023#endif  // _LIBCPP_DEBUG
4024}
4025
4026template <class _RandomAccessIterator>
4027inline _LIBCPP_INLINE_VISIBILITY
4028void
4029sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
4030{
4031    _VSTD::sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4032}
4033
4034template <class _Tp>
4035inline _LIBCPP_INLINE_VISIBILITY
4036void
4037sort(_Tp** __first, _Tp** __last)
4038{
4039    _VSTD::sort((size_t*)__first, (size_t*)__last, __less<size_t>());
4040}
4041
4042template <class _Tp>
4043inline _LIBCPP_INLINE_VISIBILITY
4044void
4045sort(__wrap_iter<_Tp*> __first, __wrap_iter<_Tp*> __last)
4046{
4047    _VSTD::sort(__first.base(), __last.base());
4048}
4049
4050template <class _Tp, class _Compare>
4051inline _LIBCPP_INLINE_VISIBILITY
4052void
4053sort(__wrap_iter<_Tp*> __first, __wrap_iter<_Tp*> __last, _Compare __comp)
4054{
4055    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4056    _VSTD::sort<_Tp*, _Comp_ref>(__first.base(), __last.base(), __comp);
4057}
4058
4059#ifdef _LIBCPP_MSVC
4060#pragma warning( push )
4061#pragma warning( disable: 4231)
4062#endif // _LIBCPP_MSVC
4063_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<char>&, char*>(char*, char*, __less<char>&))
4064_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&))
4065_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&))
4066_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&))
4067_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<short>&, short*>(short*, short*, __less<short>&))
4068_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&))
4069_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<int>&, int*>(int*, int*, __less<int>&))
4070_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&))
4071_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long>&, long*>(long*, long*, __less<long>&))
4072_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&))
4073_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long long>&, long long*>(long long*, long long*, __less<long long>&))
4074_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>&))
4075_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<float>&, float*>(float*, float*, __less<float>&))
4076_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<double>&, double*>(double*, double*, __less<double>&))
4077_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS void __sort<__less<long double>&, long double*>(long double*, long double*, __less<long double>&))
4078
4079_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<char>&, char*>(char*, char*, __less<char>&))
4080_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<wchar_t>&, wchar_t*>(wchar_t*, wchar_t*, __less<wchar_t>&))
4081_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<signed char>&, signed char*>(signed char*, signed char*, __less<signed char>&))
4082_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned char>&, unsigned char*>(unsigned char*, unsigned char*, __less<unsigned char>&))
4083_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<short>&, short*>(short*, short*, __less<short>&))
4084_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned short>&, unsigned short*>(unsigned short*, unsigned short*, __less<unsigned short>&))
4085_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<int>&, int*>(int*, int*, __less<int>&))
4086_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned>&, unsigned*>(unsigned*, unsigned*, __less<unsigned>&))
4087_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long>&, long*>(long*, long*, __less<long>&))
4088_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<unsigned long>&, unsigned long*>(unsigned long*, unsigned long*, __less<unsigned long>&))
4089_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long long>&, long long*>(long long*, long long*, __less<long long>&))
4090_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>&))
4091_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<float>&, float*>(float*, float*, __less<float>&))
4092_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<double>&, double*>(double*, double*, __less<double>&))
4093_LIBCPP_EXTERN_TEMPLATE(_LIBCPP_FUNC_VIS bool __insertion_sort_incomplete<__less<long double>&, long double*>(long double*, long double*, __less<long double>&))
4094
4095_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>&))
4096#ifdef _LIBCPP_MSVC
4097#pragma warning( pop )
4098#endif  // _LIBCPP_MSVC
4099
4100// lower_bound
4101
4102template <class _Compare, class _ForwardIterator, class _Tp>
4103_ForwardIterator
4104__lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4105{
4106    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
4107    difference_type __len = _VSTD::distance(__first, __last);
4108    while (__len != 0)
4109    {
4110        difference_type __l2 = __len / 2;
4111        _ForwardIterator __m = __first;
4112        _VSTD::advance(__m, __l2);
4113        if (__comp(*__m, __value_))
4114        {
4115            __first = ++__m;
4116            __len -= __l2 + 1;
4117        }
4118        else
4119            __len = __l2;
4120    }
4121    return __first;
4122}
4123
4124template <class _ForwardIterator, class _Tp, class _Compare>
4125inline _LIBCPP_INLINE_VISIBILITY
4126_ForwardIterator
4127lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4128{
4129#ifdef _LIBCPP_DEBUG
4130    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4131    __debug_less<_Compare> __c(__comp);
4132    return __lower_bound<_Comp_ref>(__first, __last, __value_, __c);
4133#else  // _LIBCPP_DEBUG
4134    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4135    return __lower_bound<_Comp_ref>(__first, __last, __value_, __comp);
4136#endif  // _LIBCPP_DEBUG
4137}
4138
4139template <class _ForwardIterator, class _Tp>
4140inline _LIBCPP_INLINE_VISIBILITY
4141_ForwardIterator
4142lower_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4143{
4144    return _VSTD::lower_bound(__first, __last, __value_,
4145                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
4146}
4147
4148// upper_bound
4149
4150template <class _Compare, class _ForwardIterator, class _Tp>
4151_ForwardIterator
4152__upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4153{
4154    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
4155    difference_type __len = _VSTD::distance(__first, __last);
4156    while (__len != 0)
4157    {
4158        difference_type __l2 = __len / 2;
4159        _ForwardIterator __m = __first;
4160        _VSTD::advance(__m, __l2);
4161        if (__comp(__value_, *__m))
4162            __len = __l2;
4163        else
4164        {
4165            __first = ++__m;
4166            __len -= __l2 + 1;
4167        }
4168    }
4169    return __first;
4170}
4171
4172template <class _ForwardIterator, class _Tp, class _Compare>
4173inline _LIBCPP_INLINE_VISIBILITY
4174_ForwardIterator
4175upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4176{
4177#ifdef _LIBCPP_DEBUG
4178    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4179    __debug_less<_Compare> __c(__comp);
4180    return __upper_bound<_Comp_ref>(__first, __last, __value_, __c);
4181#else  // _LIBCPP_DEBUG
4182    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4183    return __upper_bound<_Comp_ref>(__first, __last, __value_, __comp);
4184#endif  // _LIBCPP_DEBUG
4185}
4186
4187template <class _ForwardIterator, class _Tp>
4188inline _LIBCPP_INLINE_VISIBILITY
4189_ForwardIterator
4190upper_bound(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4191{
4192    return _VSTD::upper_bound(__first, __last, __value_,
4193                             __less<_Tp, typename iterator_traits<_ForwardIterator>::value_type>());
4194}
4195
4196// equal_range
4197
4198template <class _Compare, class _ForwardIterator, class _Tp>
4199pair<_ForwardIterator, _ForwardIterator>
4200__equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4201{
4202    typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
4203    difference_type __len = _VSTD::distance(__first, __last);
4204    while (__len != 0)
4205    {
4206        difference_type __l2 = __len / 2;
4207        _ForwardIterator __m = __first;
4208        _VSTD::advance(__m, __l2);
4209        if (__comp(*__m, __value_))
4210        {
4211            __first = ++__m;
4212            __len -= __l2 + 1;
4213        }
4214        else if (__comp(__value_, *__m))
4215        {
4216            __last = __m;
4217            __len = __l2;
4218        }
4219        else
4220        {
4221            _ForwardIterator __mp1 = __m;
4222            return pair<_ForwardIterator, _ForwardIterator>
4223                   (
4224                      __lower_bound<_Compare>(__first, __m, __value_, __comp),
4225                      __upper_bound<_Compare>(++__mp1, __last, __value_, __comp)
4226                   );
4227        }
4228    }
4229    return pair<_ForwardIterator, _ForwardIterator>(__first, __first);
4230}
4231
4232template <class _ForwardIterator, class _Tp, class _Compare>
4233inline _LIBCPP_INLINE_VISIBILITY
4234pair<_ForwardIterator, _ForwardIterator>
4235equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4236{
4237#ifdef _LIBCPP_DEBUG
4238    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4239    __debug_less<_Compare> __c(__comp);
4240    return __equal_range<_Comp_ref>(__first, __last, __value_, __c);
4241#else  // _LIBCPP_DEBUG
4242    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4243    return __equal_range<_Comp_ref>(__first, __last, __value_, __comp);
4244#endif  // _LIBCPP_DEBUG
4245}
4246
4247template <class _ForwardIterator, class _Tp>
4248inline _LIBCPP_INLINE_VISIBILITY
4249pair<_ForwardIterator, _ForwardIterator>
4250equal_range(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4251{
4252    return _VSTD::equal_range(__first, __last, __value_,
4253                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
4254}
4255
4256// binary_search
4257
4258template <class _Compare, class _ForwardIterator, class _Tp>
4259inline _LIBCPP_INLINE_VISIBILITY
4260bool
4261__binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4262{
4263    __first = __lower_bound<_Compare>(__first, __last, __value_, __comp);
4264    return __first != __last && !__comp(__value_, *__first);
4265}
4266
4267template <class _ForwardIterator, class _Tp, class _Compare>
4268inline _LIBCPP_INLINE_VISIBILITY
4269bool
4270binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_, _Compare __comp)
4271{
4272#ifdef _LIBCPP_DEBUG
4273    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4274    __debug_less<_Compare> __c(__comp);
4275    return __binary_search<_Comp_ref>(__first, __last, __value_, __c);
4276#else  // _LIBCPP_DEBUG
4277    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4278    return __binary_search<_Comp_ref>(__first, __last, __value_, __comp);
4279#endif  // _LIBCPP_DEBUG
4280}
4281
4282template <class _ForwardIterator, class _Tp>
4283inline _LIBCPP_INLINE_VISIBILITY
4284bool
4285binary_search(_ForwardIterator __first, _ForwardIterator __last, const _Tp& __value_)
4286{
4287    return _VSTD::binary_search(__first, __last, __value_,
4288                             __less<typename iterator_traits<_ForwardIterator>::value_type, _Tp>());
4289}
4290
4291// merge
4292
4293template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
4294_OutputIterator
4295__merge(_InputIterator1 __first1, _InputIterator1 __last1,
4296        _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
4297{
4298    for (; __first1 != __last1; ++__result)
4299    {
4300        if (__first2 == __last2)
4301            return _VSTD::copy(__first1, __last1, __result);
4302        if (__comp(*__first2, *__first1))
4303        {
4304            *__result = *__first2;
4305            ++__first2;
4306        }
4307        else
4308        {
4309            *__result = *__first1;
4310            ++__first1;
4311        }
4312    }
4313    return _VSTD::copy(__first2, __last2, __result);
4314}
4315
4316template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
4317inline _LIBCPP_INLINE_VISIBILITY
4318_OutputIterator
4319merge(_InputIterator1 __first1, _InputIterator1 __last1,
4320      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
4321{
4322#ifdef _LIBCPP_DEBUG
4323    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4324    __debug_less<_Compare> __c(__comp);
4325    return _VSTD::__merge<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
4326#else  // _LIBCPP_DEBUG
4327    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4328    return _VSTD::__merge<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
4329#endif  // _LIBCPP_DEBUG
4330}
4331
4332template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
4333inline _LIBCPP_INLINE_VISIBILITY
4334_OutputIterator
4335merge(_InputIterator1 __first1, _InputIterator1 __last1,
4336      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
4337{
4338    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
4339    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
4340    return merge(__first1, __last1, __first2, __last2, __result, __less<__v1, __v2>());
4341}
4342
4343// inplace_merge
4344
4345template <class _Compare, class _InputIterator1, class _InputIterator2,
4346          class _OutputIterator>
4347void __half_inplace_merge(_InputIterator1 __first1, _InputIterator1 __last1,
4348                          _InputIterator2 __first2, _InputIterator2 __last2,
4349                          _OutputIterator __result, _Compare __comp)
4350{
4351    for (; __first1 != __last1; ++__result)
4352    {
4353        if (__first2 == __last2)
4354        {
4355            _VSTD::move(__first1, __last1, __result);
4356            return;
4357        }
4358
4359        if (__comp(*__first2, *__first1))
4360        {
4361            *__result = _VSTD::move(*__first2);
4362            ++__first2;
4363        }
4364        else
4365        {
4366            *__result = _VSTD::move(*__first1);
4367            ++__first1;
4368        }
4369    }
4370    // __first2 through __last2 are already in the right spot.
4371}
4372
4373template <class _Compare, class _BidirectionalIterator>
4374void
4375__buffered_inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
4376                _Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
4377                                 typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
4378                typename iterator_traits<_BidirectionalIterator>::value_type* __buff)
4379{
4380    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
4381    __destruct_n __d(0);
4382    unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
4383    if (__len1 <= __len2)
4384    {
4385        value_type* __p = __buff;
4386        for (_BidirectionalIterator __i = __first; __i != __middle; __d.__incr((value_type*)0), (void) ++__i, ++__p)
4387            ::new(__p) value_type(_VSTD::move(*__i));
4388        __half_inplace_merge(__buff, __p, __middle, __last, __first, __comp);
4389    }
4390    else
4391    {
4392        value_type* __p = __buff;
4393        for (_BidirectionalIterator __i = __middle; __i != __last; __d.__incr((value_type*)0), (void) ++__i, ++__p)
4394            ::new(__p) value_type(_VSTD::move(*__i));
4395        typedef reverse_iterator<_BidirectionalIterator> _RBi;
4396        typedef reverse_iterator<value_type*> _Rv;
4397        __half_inplace_merge(_Rv(__p), _Rv(__buff),
4398                             _RBi(__middle), _RBi(__first),
4399                             _RBi(__last), __negate<_Compare>(__comp));
4400    }
4401}
4402
4403template <class _Compare, class _BidirectionalIterator>
4404void
4405__inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
4406                _Compare __comp, typename iterator_traits<_BidirectionalIterator>::difference_type __len1,
4407                                 typename iterator_traits<_BidirectionalIterator>::difference_type __len2,
4408                typename iterator_traits<_BidirectionalIterator>::value_type* __buff, ptrdiff_t __buff_size)
4409{
4410    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
4411    while (true)
4412    {
4413        // if __middle == __last, we're done
4414        if (__len2 == 0)
4415            return;
4416        if (__len1 <= __buff_size || __len2 <= __buff_size)
4417            return __buffered_inplace_merge<_Compare>
4418                   (__first, __middle, __last, __comp, __len1, __len2, __buff);
4419        // shrink [__first, __middle) as much as possible (with no moves), returning if it shrinks to 0
4420        for (; true; ++__first, (void) --__len1)
4421        {
4422            if (__len1 == 0)
4423                return;
4424            if (__comp(*__middle, *__first))
4425                break;
4426        }
4427        // __first < __middle < __last
4428        // *__first > *__middle
4429        // partition [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last) such that
4430        //     all elements in:
4431        //         [__first, __m1)  <= [__middle, __m2)
4432        //         [__middle, __m2) <  [__m1, __middle)
4433        //         [__m1, __middle) <= [__m2, __last)
4434        //     and __m1 or __m2 is in the middle of its range
4435        _BidirectionalIterator __m1;  // "median" of [__first, __middle)
4436        _BidirectionalIterator __m2;  // "median" of [__middle, __last)
4437        difference_type __len11;      // distance(__first, __m1)
4438        difference_type __len21;      // distance(__middle, __m2)
4439        // binary search smaller range
4440        if (__len1 < __len2)
4441        {   // __len >= 1, __len2 >= 2
4442            __len21 = __len2 / 2;
4443            __m2 = __middle;
4444            _VSTD::advance(__m2, __len21);
4445            __m1 = __upper_bound<_Compare>(__first, __middle, *__m2, __comp);
4446            __len11 = _VSTD::distance(__first, __m1);
4447        }
4448        else
4449        {
4450            if (__len1 == 1)
4451            {   // __len1 >= __len2 && __len2 > 0, therefore __len2 == 1
4452                // It is known *__first > *__middle
4453                swap(*__first, *__middle);
4454                return;
4455            }
4456            // __len1 >= 2, __len2 >= 1
4457            __len11 = __len1 / 2;
4458            __m1 = __first;
4459            _VSTD::advance(__m1, __len11);
4460            __m2 = __lower_bound<_Compare>(__middle, __last, *__m1, __comp);
4461            __len21 = _VSTD::distance(__middle, __m2);
4462        }
4463        difference_type __len12 = __len1 - __len11;  // distance(__m1, __middle)
4464        difference_type __len22 = __len2 - __len21;  // distance(__m2, __last)
4465        // [__first, __m1) [__m1, __middle) [__middle, __m2) [__m2, __last)
4466        // swap middle two partitions
4467        __middle = _VSTD::rotate(__m1, __middle, __m2);
4468        // __len12 and __len21 now have swapped meanings
4469        // merge smaller range with recurisve call and larger with tail recursion elimination
4470        if (__len11 + __len21 < __len12 + __len22)
4471        {
4472            __inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
4473//          __inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
4474            __first = __middle;
4475            __middle = __m2;
4476            __len1 = __len12;
4477            __len2 = __len22;
4478        }
4479        else
4480        {
4481            __inplace_merge<_Compare>(__middle, __m2, __last, __comp, __len12, __len22, __buff, __buff_size);
4482//          __inplace_merge<_Compare>(__first, __m1, __middle, __comp, __len11, __len21, __buff, __buff_size);
4483            __last = __middle;
4484            __middle = __m1;
4485            __len1 = __len11;
4486            __len2 = __len21;
4487        }
4488    }
4489}
4490
4491template <class _BidirectionalIterator, class _Compare>
4492inline _LIBCPP_INLINE_VISIBILITY
4493void
4494inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last,
4495              _Compare __comp)
4496{
4497    typedef typename iterator_traits<_BidirectionalIterator>::value_type value_type;
4498    typedef typename iterator_traits<_BidirectionalIterator>::difference_type difference_type;
4499    difference_type __len1 = _VSTD::distance(__first, __middle);
4500    difference_type __len2 = _VSTD::distance(__middle, __last);
4501    difference_type __buf_size = _VSTD::min(__len1, __len2);
4502    pair<value_type*, ptrdiff_t> __buf = _VSTD::get_temporary_buffer<value_type>(__buf_size);
4503    unique_ptr<value_type, __return_temporary_buffer> __h(__buf.first);
4504
4505#ifdef _LIBCPP_DEBUG
4506    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4507    __debug_less<_Compare> __c(__comp);
4508    return _VSTD::__inplace_merge<_Comp_ref>(__first, __middle, __last, __c, __len1, __len2,
4509                                            __buf.first, __buf.second);
4510#else  // _LIBCPP_DEBUG
4511    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4512    return _VSTD::__inplace_merge<_Comp_ref>(__first, __middle, __last, __comp, __len1, __len2,
4513                                            __buf.first, __buf.second);
4514#endif  // _LIBCPP_DEBUG
4515}
4516
4517template <class _BidirectionalIterator>
4518inline _LIBCPP_INLINE_VISIBILITY
4519void
4520inplace_merge(_BidirectionalIterator __first, _BidirectionalIterator __middle, _BidirectionalIterator __last)
4521{
4522    _VSTD::inplace_merge(__first, __middle, __last,
4523                        __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
4524}
4525
4526// stable_sort
4527
4528template <class _Compare, class _InputIterator1, class _InputIterator2>
4529void
4530__merge_move_construct(_InputIterator1 __first1, _InputIterator1 __last1,
4531        _InputIterator2 __first2, _InputIterator2 __last2,
4532        typename iterator_traits<_InputIterator1>::value_type* __result, _Compare __comp)
4533{
4534    typedef typename iterator_traits<_InputIterator1>::value_type value_type;
4535    __destruct_n __d(0);
4536    unique_ptr<value_type, __destruct_n&> __h(__result, __d);
4537    for (; true; ++__result)
4538    {
4539        if (__first1 == __last1)
4540        {
4541            for (; __first2 != __last2; ++__first2, ++__result, __d.__incr((value_type*)0))
4542                ::new (__result) value_type(_VSTD::move(*__first2));
4543            __h.release();
4544            return;
4545        }
4546        if (__first2 == __last2)
4547        {
4548            for (; __first1 != __last1; ++__first1, ++__result, __d.__incr((value_type*)0))
4549                ::new (__result) value_type(_VSTD::move(*__first1));
4550            __h.release();
4551            return;
4552        }
4553        if (__comp(*__first2, *__first1))
4554        {
4555            ::new (__result) value_type(_VSTD::move(*__first2));
4556            __d.__incr((value_type*)0);
4557            ++__first2;
4558        }
4559        else
4560        {
4561            ::new (__result) value_type(_VSTD::move(*__first1));
4562            __d.__incr((value_type*)0);
4563            ++__first1;
4564        }
4565    }
4566}
4567
4568template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
4569void
4570__merge_move_assign(_InputIterator1 __first1, _InputIterator1 __last1,
4571        _InputIterator2 __first2, _InputIterator2 __last2,
4572        _OutputIterator __result, _Compare __comp)
4573{
4574    for (; __first1 != __last1; ++__result)
4575    {
4576        if (__first2 == __last2)
4577        {
4578            for (; __first1 != __last1; ++__first1, ++__result)
4579                *__result = _VSTD::move(*__first1);
4580            return;
4581        }
4582        if (__comp(*__first2, *__first1))
4583        {
4584            *__result = _VSTD::move(*__first2);
4585            ++__first2;
4586        }
4587        else
4588        {
4589            *__result = _VSTD::move(*__first1);
4590            ++__first1;
4591        }
4592    }
4593    for (; __first2 != __last2; ++__first2, ++__result)
4594        *__result = _VSTD::move(*__first2);
4595}
4596
4597template <class _Compare, class _RandomAccessIterator>
4598void
4599__stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4600              typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4601              typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size);
4602
4603template <class _Compare, class _RandomAccessIterator>
4604void
4605__stable_sort_move(_RandomAccessIterator __first1, _RandomAccessIterator __last1, _Compare __comp,
4606                   typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4607                   typename iterator_traits<_RandomAccessIterator>::value_type* __first2)
4608{
4609    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4610    switch (__len)
4611    {
4612    case 0:
4613        return;
4614    case 1:
4615        ::new(__first2) value_type(_VSTD::move(*__first1));
4616        return;
4617    case 2:
4618       __destruct_n __d(0);
4619        unique_ptr<value_type, __destruct_n&> __h2(__first2, __d);
4620         if (__comp(*--__last1, *__first1))
4621        {
4622            ::new(__first2) value_type(_VSTD::move(*__last1));
4623            __d.__incr((value_type*)0);
4624            ++__first2;
4625            ::new(__first2) value_type(_VSTD::move(*__first1));
4626        }
4627        else
4628        {
4629            ::new(__first2) value_type(_VSTD::move(*__first1));
4630            __d.__incr((value_type*)0);
4631            ++__first2;
4632            ::new(__first2) value_type(_VSTD::move(*__last1));
4633        }
4634        __h2.release();
4635        return;
4636    }
4637    if (__len <= 8)
4638    {
4639        __insertion_sort_move<_Compare>(__first1, __last1, __first2, __comp);
4640        return;
4641    }
4642    typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
4643    _RandomAccessIterator __m = __first1 + __l2;
4644    __stable_sort<_Compare>(__first1, __m, __comp, __l2, __first2, __l2);
4645    __stable_sort<_Compare>(__m, __last1, __comp, __len - __l2, __first2 + __l2, __len - __l2);
4646    __merge_move_construct<_Compare>(__first1, __m, __m, __last1, __first2, __comp);
4647}
4648
4649template <class _Tp>
4650struct __stable_sort_switch
4651{
4652    static const unsigned value = 128*is_trivially_copy_assignable<_Tp>::value;
4653};
4654
4655template <class _Compare, class _RandomAccessIterator>
4656void
4657__stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4658              typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4659              typename iterator_traits<_RandomAccessIterator>::value_type* __buff, ptrdiff_t __buff_size)
4660{
4661    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4662    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4663    switch (__len)
4664    {
4665    case 0:
4666    case 1:
4667        return;
4668    case 2:
4669        if (__comp(*--__last, *__first))
4670            swap(*__first, *__last);
4671        return;
4672    }
4673    if (__len <= static_cast<difference_type>(__stable_sort_switch<value_type>::value))
4674    {
4675        __insertion_sort<_Compare>(__first, __last, __comp);
4676        return;
4677    }
4678    typename iterator_traits<_RandomAccessIterator>::difference_type __l2 = __len / 2;
4679    _RandomAccessIterator __m = __first + __l2;
4680    if (__len <= __buff_size)
4681    {
4682        __destruct_n __d(0);
4683        unique_ptr<value_type, __destruct_n&> __h2(__buff, __d);
4684        __stable_sort_move<_Compare>(__first, __m, __comp, __l2, __buff);
4685        __d.__set(__l2, (value_type*)0);
4686        __stable_sort_move<_Compare>(__m, __last, __comp, __len - __l2, __buff + __l2);
4687        __d.__set(__len, (value_type*)0);
4688        __merge_move_assign<_Compare>(__buff, __buff + __l2, __buff + __l2, __buff + __len, __first, __comp);
4689//         __merge<_Compare>(move_iterator<value_type*>(__buff),
4690//                           move_iterator<value_type*>(__buff + __l2),
4691//                           move_iterator<_RandomAccessIterator>(__buff + __l2),
4692//                           move_iterator<_RandomAccessIterator>(__buff + __len),
4693//                           __first, __comp);
4694        return;
4695    }
4696    __stable_sort<_Compare>(__first, __m, __comp, __l2, __buff, __buff_size);
4697    __stable_sort<_Compare>(__m, __last, __comp, __len - __l2, __buff, __buff_size);
4698    __inplace_merge<_Compare>(__first, __m, __last, __comp, __l2, __len - __l2, __buff, __buff_size);
4699}
4700
4701template <class _RandomAccessIterator, class _Compare>
4702inline _LIBCPP_INLINE_VISIBILITY
4703void
4704stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4705{
4706    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4707    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4708    difference_type __len = __last - __first;
4709    pair<value_type*, ptrdiff_t> __buf(0, 0);
4710    unique_ptr<value_type, __return_temporary_buffer> __h;
4711    if (__len > static_cast<difference_type>(__stable_sort_switch<value_type>::value))
4712    {
4713        __buf = _VSTD::get_temporary_buffer<value_type>(__len);
4714        __h.reset(__buf.first);
4715    }
4716#ifdef _LIBCPP_DEBUG
4717    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4718    __debug_less<_Compare> __c(__comp);
4719    __stable_sort<_Comp_ref>(__first, __last, __c, __len, __buf.first, __buf.second);
4720#else  // _LIBCPP_DEBUG
4721    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4722    __stable_sort<_Comp_ref>(__first, __last, __comp, __len, __buf.first, __buf.second);
4723#endif  // _LIBCPP_DEBUG
4724}
4725
4726template <class _RandomAccessIterator>
4727inline _LIBCPP_INLINE_VISIBILITY
4728void
4729stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last)
4730{
4731    _VSTD::stable_sort(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4732}
4733
4734// is_heap_until
4735
4736template <class _RandomAccessIterator, class _Compare>
4737_RandomAccessIterator
4738is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4739{
4740    typedef typename _VSTD::iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4741    difference_type __len = __last - __first;
4742    difference_type __p = 0;
4743    difference_type __c = 1;
4744    _RandomAccessIterator __pp = __first;
4745    while (__c < __len)
4746    {
4747        _RandomAccessIterator __cp = __first + __c;
4748        if (__comp(*__pp, *__cp))
4749            return __cp;
4750        ++__c;
4751        ++__cp;
4752        if (__c == __len)
4753            return __last;
4754        if (__comp(*__pp, *__cp))
4755            return __cp;
4756        ++__p;
4757        ++__pp;
4758        __c = 2 * __p + 1;
4759    }
4760    return __last;
4761}
4762
4763template<class _RandomAccessIterator>
4764inline _LIBCPP_INLINE_VISIBILITY
4765_RandomAccessIterator
4766is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last)
4767{
4768    return _VSTD::is_heap_until(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4769}
4770
4771// is_heap
4772
4773template <class _RandomAccessIterator, class _Compare>
4774inline _LIBCPP_INLINE_VISIBILITY
4775bool
4776is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4777{
4778    return _VSTD::is_heap_until(__first, __last, __comp) == __last;
4779}
4780
4781template<class _RandomAccessIterator>
4782inline _LIBCPP_INLINE_VISIBILITY
4783bool
4784is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
4785{
4786    return _VSTD::is_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4787}
4788
4789// push_heap
4790
4791template <class _Compare, class _RandomAccessIterator>
4792void
4793__sift_up(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4794          typename iterator_traits<_RandomAccessIterator>::difference_type __len)
4795{
4796    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4797    if (__len > 1)
4798    {
4799        __len = (__len - 2) / 2;
4800        _RandomAccessIterator __ptr = __first + __len;
4801        if (__comp(*__ptr, *--__last))
4802        {
4803            value_type __t(_VSTD::move(*__last));
4804            do
4805            {
4806                *__last = _VSTD::move(*__ptr);
4807                __last = __ptr;
4808                if (__len == 0)
4809                    break;
4810                __len = (__len - 1) / 2;
4811                __ptr = __first + __len;
4812            } while (__comp(*__ptr, __t));
4813            *__last = _VSTD::move(__t);
4814        }
4815    }
4816}
4817
4818template <class _RandomAccessIterator, class _Compare>
4819inline _LIBCPP_INLINE_VISIBILITY
4820void
4821push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4822{
4823#ifdef _LIBCPP_DEBUG
4824    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4825    __debug_less<_Compare> __c(__comp);
4826    __sift_up<_Comp_ref>(__first, __last, __c, __last - __first);
4827#else  // _LIBCPP_DEBUG
4828    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4829    __sift_up<_Comp_ref>(__first, __last, __comp, __last - __first);
4830#endif  // _LIBCPP_DEBUG
4831}
4832
4833template <class _RandomAccessIterator>
4834inline _LIBCPP_INLINE_VISIBILITY
4835void
4836push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
4837{
4838    _VSTD::push_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4839}
4840
4841// pop_heap
4842
4843template <class _Compare, class _RandomAccessIterator>
4844void
4845__sift_down(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4846            typename iterator_traits<_RandomAccessIterator>::difference_type __len,
4847            _RandomAccessIterator __start)
4848{
4849    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4850    typedef typename iterator_traits<_RandomAccessIterator>::value_type value_type;
4851    // left-child of __start is at 2 * __start + 1
4852    // right-child of __start is at 2 * __start + 2
4853    difference_type __child = __start - __first;
4854
4855    if (__len < 2 || (__len - 2) / 2 < __child)
4856        return;
4857
4858    __child = 2 * __child + 1;
4859    _RandomAccessIterator __child_i = __first + __child;
4860
4861    if ((__child + 1) < __len && __comp(*__child_i, *(__child_i + 1))) {
4862        // right-child exists and is greater than left-child
4863        ++__child_i;
4864        ++__child;
4865    }
4866
4867    // check if we are in heap-order
4868    if (__comp(*__child_i, *__start))
4869        // we are, __start is larger than it's largest child
4870        return;
4871
4872    value_type __top(_VSTD::move(*__start));
4873    do
4874    {
4875        // we are not in heap-order, swap the parent with it's largest child
4876        *__start = _VSTD::move(*__child_i);
4877        __start = __child_i;
4878
4879        if ((__len - 2) / 2 < __child)
4880            break;
4881
4882        // recompute the child based off of the updated parent
4883        __child = 2 * __child + 1;
4884        __child_i = __first + __child;
4885
4886        if ((__child + 1) < __len && __comp(*__child_i, *(__child_i + 1))) {
4887            // right-child exists and is greater than left-child
4888            ++__child_i;
4889            ++__child;
4890        }
4891
4892        // check if we are in heap-order
4893    } while (!__comp(*__child_i, __top));
4894    *__start = _VSTD::move(__top);
4895}
4896
4897template <class _Compare, class _RandomAccessIterator>
4898inline _LIBCPP_INLINE_VISIBILITY
4899void
4900__pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp,
4901           typename iterator_traits<_RandomAccessIterator>::difference_type __len)
4902{
4903    if (__len > 1)
4904    {
4905        swap(*__first, *--__last);
4906        __sift_down<_Compare>(__first, __last, __comp, __len - 1, __first);
4907    }
4908}
4909
4910template <class _RandomAccessIterator, class _Compare>
4911inline _LIBCPP_INLINE_VISIBILITY
4912void
4913pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4914{
4915#ifdef _LIBCPP_DEBUG
4916    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4917    __debug_less<_Compare> __c(__comp);
4918    __pop_heap<_Comp_ref>(__first, __last, __c, __last - __first);
4919#else  // _LIBCPP_DEBUG
4920    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4921    __pop_heap<_Comp_ref>(__first, __last, __comp, __last - __first);
4922#endif  // _LIBCPP_DEBUG
4923}
4924
4925template <class _RandomAccessIterator>
4926inline _LIBCPP_INLINE_VISIBILITY
4927void
4928pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
4929{
4930    _VSTD::pop_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4931}
4932
4933// make_heap
4934
4935template <class _Compare, class _RandomAccessIterator>
4936void
4937__make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4938{
4939    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4940    difference_type __n = __last - __first;
4941    if (__n > 1)
4942    {
4943        // start from the first parent, there is no need to consider children
4944        for (difference_type __start = (__n - 2) / 2; __start >= 0; --__start)
4945        {
4946            __sift_down<_Compare>(__first, __last, __comp, __n, __first + __start);
4947        }
4948    }
4949}
4950
4951template <class _RandomAccessIterator, class _Compare>
4952inline _LIBCPP_INLINE_VISIBILITY
4953void
4954make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4955{
4956#ifdef _LIBCPP_DEBUG
4957    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4958    __debug_less<_Compare> __c(__comp);
4959    __make_heap<_Comp_ref>(__first, __last, __c);
4960#else  // _LIBCPP_DEBUG
4961    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4962    __make_heap<_Comp_ref>(__first, __last, __comp);
4963#endif  // _LIBCPP_DEBUG
4964}
4965
4966template <class _RandomAccessIterator>
4967inline _LIBCPP_INLINE_VISIBILITY
4968void
4969make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
4970{
4971    _VSTD::make_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
4972}
4973
4974// sort_heap
4975
4976template <class _Compare, class _RandomAccessIterator>
4977void
4978__sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4979{
4980    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
4981    for (difference_type __n = __last - __first; __n > 1; --__last, --__n)
4982        __pop_heap<_Compare>(__first, __last, __comp, __n);
4983}
4984
4985template <class _RandomAccessIterator, class _Compare>
4986inline _LIBCPP_INLINE_VISIBILITY
4987void
4988sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
4989{
4990#ifdef _LIBCPP_DEBUG
4991    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
4992    __debug_less<_Compare> __c(__comp);
4993    __sort_heap<_Comp_ref>(__first, __last, __c);
4994#else  // _LIBCPP_DEBUG
4995    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
4996    __sort_heap<_Comp_ref>(__first, __last, __comp);
4997#endif  // _LIBCPP_DEBUG
4998}
4999
5000template <class _RandomAccessIterator>
5001inline _LIBCPP_INLINE_VISIBILITY
5002void
5003sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
5004{
5005    _VSTD::sort_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5006}
5007
5008// partial_sort
5009
5010template <class _Compare, class _RandomAccessIterator>
5011void
5012__partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
5013             _Compare __comp)
5014{
5015    __make_heap<_Compare>(__first, __middle, __comp);
5016    typename iterator_traits<_RandomAccessIterator>::difference_type __len = __middle - __first;
5017    for (_RandomAccessIterator __i = __middle; __i != __last; ++__i)
5018    {
5019        if (__comp(*__i, *__first))
5020        {
5021            swap(*__i, *__first);
5022            __sift_down<_Compare>(__first, __middle, __comp, __len, __first);
5023        }
5024    }
5025    __sort_heap<_Compare>(__first, __middle, __comp);
5026}
5027
5028template <class _RandomAccessIterator, class _Compare>
5029inline _LIBCPP_INLINE_VISIBILITY
5030void
5031partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last,
5032             _Compare __comp)
5033{
5034#ifdef _LIBCPP_DEBUG
5035    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5036    __debug_less<_Compare> __c(__comp);
5037    __partial_sort<_Comp_ref>(__first, __middle, __last, __c);
5038#else  // _LIBCPP_DEBUG
5039    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5040    __partial_sort<_Comp_ref>(__first, __middle, __last, __comp);
5041#endif  // _LIBCPP_DEBUG
5042}
5043
5044template <class _RandomAccessIterator>
5045inline _LIBCPP_INLINE_VISIBILITY
5046void
5047partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)
5048{
5049    _VSTD::partial_sort(__first, __middle, __last,
5050                       __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5051}
5052
5053// partial_sort_copy
5054
5055template <class _Compare, class _InputIterator, class _RandomAccessIterator>
5056_RandomAccessIterator
5057__partial_sort_copy(_InputIterator __first, _InputIterator __last,
5058                    _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
5059{
5060    _RandomAccessIterator __r = __result_first;
5061    if (__r != __result_last)
5062    {
5063        for (; __first != __last && __r != __result_last; (void) ++__first, ++__r)
5064            *__r = *__first;
5065        __make_heap<_Compare>(__result_first, __r, __comp);
5066        typename iterator_traits<_RandomAccessIterator>::difference_type __len = __r - __result_first;
5067        for (; __first != __last; ++__first)
5068            if (__comp(*__first, *__result_first))
5069            {
5070                *__result_first = *__first;
5071                __sift_down<_Compare>(__result_first, __r, __comp, __len, __result_first);
5072            }
5073        __sort_heap<_Compare>(__result_first, __r, __comp);
5074    }
5075    return __r;
5076}
5077
5078template <class _InputIterator, class _RandomAccessIterator, class _Compare>
5079inline _LIBCPP_INLINE_VISIBILITY
5080_RandomAccessIterator
5081partial_sort_copy(_InputIterator __first, _InputIterator __last,
5082                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
5083{
5084#ifdef _LIBCPP_DEBUG
5085    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5086    __debug_less<_Compare> __c(__comp);
5087    return __partial_sort_copy<_Comp_ref>(__first, __last, __result_first, __result_last, __c);
5088#else  // _LIBCPP_DEBUG
5089    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5090    return __partial_sort_copy<_Comp_ref>(__first, __last, __result_first, __result_last, __comp);
5091#endif  // _LIBCPP_DEBUG
5092}
5093
5094template <class _InputIterator, class _RandomAccessIterator>
5095inline _LIBCPP_INLINE_VISIBILITY
5096_RandomAccessIterator
5097partial_sort_copy(_InputIterator __first, _InputIterator __last,
5098                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last)
5099{
5100    return _VSTD::partial_sort_copy(__first, __last, __result_first, __result_last,
5101                                   __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5102}
5103
5104// nth_element
5105
5106template <class _Compare, class _RandomAccessIterator>
5107void
5108__nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp)
5109{
5110    // _Compare is known to be a reference type
5111    typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
5112    const difference_type __limit = 7;
5113    while (true)
5114    {
5115    __restart:
5116        if (__nth == __last)
5117            return;
5118        difference_type __len = __last - __first;
5119        switch (__len)
5120        {
5121        case 0:
5122        case 1:
5123            return;
5124        case 2:
5125            if (__comp(*--__last, *__first))
5126                swap(*__first, *__last);
5127            return;
5128        case 3:
5129            {
5130            _RandomAccessIterator __m = __first;
5131            _VSTD::__sort3<_Compare>(__first, ++__m, --__last, __comp);
5132            return;
5133            }
5134        }
5135        if (__len <= __limit)
5136        {
5137            __selection_sort<_Compare>(__first, __last, __comp);
5138            return;
5139        }
5140        // __len > __limit >= 3
5141        _RandomAccessIterator __m = __first + __len/2;
5142        _RandomAccessIterator __lm1 = __last;
5143        unsigned __n_swaps = _VSTD::__sort3<_Compare>(__first, __m, --__lm1, __comp);
5144        // *__m is median
5145        // partition [__first, __m) < *__m and *__m <= [__m, __last)
5146        // (this inhibits tossing elements equivalent to __m around unnecessarily)
5147        _RandomAccessIterator __i = __first;
5148        _RandomAccessIterator __j = __lm1;
5149        // j points beyond range to be tested, *__lm1 is known to be <= *__m
5150        // The search going up is known to be guarded but the search coming down isn't.
5151        // Prime the downward search with a guard.
5152        if (!__comp(*__i, *__m))  // if *__first == *__m
5153        {
5154            // *__first == *__m, *__first doesn't go in first part
5155            // manually guard downward moving __j against __i
5156            while (true)
5157            {
5158                if (__i == --__j)
5159                {
5160                    // *__first == *__m, *__m <= all other elements
5161                    // Parition instead into [__first, __i) == *__first and *__first < [__i, __last)
5162                    ++__i;  // __first + 1
5163                    __j = __last;
5164                    if (!__comp(*__first, *--__j))  // we need a guard if *__first == *(__last-1)
5165                    {
5166                        while (true)
5167                        {
5168                            if (__i == __j)
5169                                return;  // [__first, __last) all equivalent elements
5170                            if (__comp(*__first, *__i))
5171                            {
5172                                swap(*__i, *__j);
5173                                ++__n_swaps;
5174                                ++__i;
5175                                break;
5176                            }
5177                            ++__i;
5178                        }
5179                    }
5180                    // [__first, __i) == *__first and *__first < [__j, __last) and __j == __last - 1
5181                    if (__i == __j)
5182                        return;
5183                    while (true)
5184                    {
5185                        while (!__comp(*__first, *__i))
5186                            ++__i;
5187                        while (__comp(*__first, *--__j))
5188                            ;
5189                        if (__i >= __j)
5190                            break;
5191                        swap(*__i, *__j);
5192                        ++__n_swaps;
5193                        ++__i;
5194                    }
5195                    // [__first, __i) == *__first and *__first < [__i, __last)
5196                    // The first part is sorted,
5197                    if (__nth < __i)
5198                        return;
5199                    // __nth_element the secod part
5200                    // __nth_element<_Compare>(__i, __nth, __last, __comp);
5201                    __first = __i;
5202                    goto __restart;
5203                }
5204                if (__comp(*__j, *__m))
5205                {
5206                    swap(*__i, *__j);
5207                    ++__n_swaps;
5208                    break;  // found guard for downward moving __j, now use unguarded partition
5209                }
5210            }
5211        }
5212        ++__i;
5213        // j points beyond range to be tested, *__lm1 is known to be <= *__m
5214        // if not yet partitioned...
5215        if (__i < __j)
5216        {
5217            // known that *(__i - 1) < *__m
5218            while (true)
5219            {
5220                // __m still guards upward moving __i
5221                while (__comp(*__i, *__m))
5222                    ++__i;
5223                // It is now known that a guard exists for downward moving __j
5224                while (!__comp(*--__j, *__m))
5225                    ;
5226                if (__i >= __j)
5227                    break;
5228                swap(*__i, *__j);
5229                ++__n_swaps;
5230                // It is known that __m != __j
5231                // If __m just moved, follow it
5232                if (__m == __i)
5233                    __m = __j;
5234                ++__i;
5235            }
5236        }
5237        // [__first, __i) < *__m and *__m <= [__i, __last)
5238        if (__i != __m && __comp(*__m, *__i))
5239        {
5240            swap(*__i, *__m);
5241            ++__n_swaps;
5242        }
5243        // [__first, __i) < *__i and *__i <= [__i+1, __last)
5244        if (__nth == __i)
5245            return;
5246        if (__n_swaps == 0)
5247        {
5248            // We were given a perfectly partitioned sequence.  Coincidence?
5249            if (__nth < __i)
5250            {
5251                // Check for [__first, __i) already sorted
5252                __j = __m = __first;
5253                while (++__j != __i)
5254                {
5255                    if (__comp(*__j, *__m))
5256                        // not yet sorted, so sort
5257                        goto not_sorted;
5258                    __m = __j;
5259                }
5260                // [__first, __i) sorted
5261                return;
5262            }
5263            else
5264            {
5265                // Check for [__i, __last) already sorted
5266                __j = __m = __i;
5267                while (++__j != __last)
5268                {
5269                    if (__comp(*__j, *__m))
5270                        // not yet sorted, so sort
5271                        goto not_sorted;
5272                    __m = __j;
5273                }
5274                // [__i, __last) sorted
5275                return;
5276            }
5277        }
5278not_sorted:
5279        // __nth_element on range containing __nth
5280        if (__nth < __i)
5281        {
5282            // __nth_element<_Compare>(__first, __nth, __i, __comp);
5283            __last = __i;
5284        }
5285        else
5286        {
5287            // __nth_element<_Compare>(__i+1, __nth, __last, __comp);
5288            __first = ++__i;
5289        }
5290    }
5291}
5292
5293template <class _RandomAccessIterator, class _Compare>
5294inline _LIBCPP_INLINE_VISIBILITY
5295void
5296nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last, _Compare __comp)
5297{
5298#ifdef _LIBCPP_DEBUG
5299    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5300    __debug_less<_Compare> __c(__comp);
5301    __nth_element<_Comp_ref>(__first, __nth, __last, __c);
5302#else  // _LIBCPP_DEBUG
5303    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5304    __nth_element<_Comp_ref>(__first, __nth, __last, __comp);
5305#endif  // _LIBCPP_DEBUG
5306}
5307
5308template <class _RandomAccessIterator>
5309inline _LIBCPP_INLINE_VISIBILITY
5310void
5311nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth, _RandomAccessIterator __last)
5312{
5313    _VSTD::nth_element(__first, __nth, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
5314}
5315
5316// includes
5317
5318template <class _Compare, class _InputIterator1, class _InputIterator2>
5319bool
5320__includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
5321           _Compare __comp)
5322{
5323    for (; __first2 != __last2; ++__first1)
5324    {
5325        if (__first1 == __last1 || __comp(*__first2, *__first1))
5326            return false;
5327        if (!__comp(*__first1, *__first2))
5328            ++__first2;
5329    }
5330    return true;
5331}
5332
5333template <class _InputIterator1, class _InputIterator2, class _Compare>
5334inline _LIBCPP_INLINE_VISIBILITY
5335bool
5336includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2,
5337         _Compare __comp)
5338{
5339#ifdef _LIBCPP_DEBUG
5340    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5341    __debug_less<_Compare> __c(__comp);
5342    return __includes<_Comp_ref>(__first1, __last1, __first2, __last2, __c);
5343#else  // _LIBCPP_DEBUG
5344    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5345    return __includes<_Comp_ref>(__first1, __last1, __first2, __last2, __comp);
5346#endif  // _LIBCPP_DEBUG
5347}
5348
5349template <class _InputIterator1, class _InputIterator2>
5350inline _LIBCPP_INLINE_VISIBILITY
5351bool
5352includes(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2)
5353{
5354    return _VSTD::includes(__first1, __last1, __first2, __last2,
5355                          __less<typename iterator_traits<_InputIterator1>::value_type,
5356                                 typename iterator_traits<_InputIterator2>::value_type>());
5357}
5358
5359// set_union
5360
5361template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5362_OutputIterator
5363__set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5364            _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5365{
5366    for (; __first1 != __last1; ++__result)
5367    {
5368        if (__first2 == __last2)
5369            return _VSTD::copy(__first1, __last1, __result);
5370        if (__comp(*__first2, *__first1))
5371        {
5372            *__result = *__first2;
5373            ++__first2;
5374        }
5375        else
5376        {
5377            *__result = *__first1;
5378            if (!__comp(*__first1, *__first2))
5379                ++__first2;
5380            ++__first1;
5381        }
5382    }
5383    return _VSTD::copy(__first2, __last2, __result);
5384}
5385
5386template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5387inline _LIBCPP_INLINE_VISIBILITY
5388_OutputIterator
5389set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5390          _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5391{
5392#ifdef _LIBCPP_DEBUG
5393    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5394    __debug_less<_Compare> __c(__comp);
5395    return __set_union<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5396#else  // _LIBCPP_DEBUG
5397    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5398    return __set_union<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5399#endif  // _LIBCPP_DEBUG
5400}
5401
5402template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5403inline _LIBCPP_INLINE_VISIBILITY
5404_OutputIterator
5405set_union(_InputIterator1 __first1, _InputIterator1 __last1,
5406          _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5407{
5408    return _VSTD::set_union(__first1, __last1, __first2, __last2, __result,
5409                          __less<typename iterator_traits<_InputIterator1>::value_type,
5410                                 typename iterator_traits<_InputIterator2>::value_type>());
5411}
5412
5413// set_intersection
5414
5415template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5416_OutputIterator
5417__set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5418                   _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5419{
5420    while (__first1 != __last1 && __first2 != __last2)
5421    {
5422        if (__comp(*__first1, *__first2))
5423            ++__first1;
5424        else
5425        {
5426            if (!__comp(*__first2, *__first1))
5427            {
5428                *__result = *__first1;
5429                ++__result;
5430                ++__first1;
5431            }
5432            ++__first2;
5433        }
5434    }
5435    return __result;
5436}
5437
5438template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5439inline _LIBCPP_INLINE_VISIBILITY
5440_OutputIterator
5441set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5442                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5443{
5444#ifdef _LIBCPP_DEBUG
5445    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5446    __debug_less<_Compare> __c(__comp);
5447    return __set_intersection<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5448#else  // _LIBCPP_DEBUG
5449    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5450    return __set_intersection<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5451#endif  // _LIBCPP_DEBUG
5452}
5453
5454template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5455inline _LIBCPP_INLINE_VISIBILITY
5456_OutputIterator
5457set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,
5458                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5459{
5460    return _VSTD::set_intersection(__first1, __last1, __first2, __last2, __result,
5461                                  __less<typename iterator_traits<_InputIterator1>::value_type,
5462                                         typename iterator_traits<_InputIterator2>::value_type>());
5463}
5464
5465// set_difference
5466
5467template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5468_OutputIterator
5469__set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5470                 _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5471{
5472    while (__first1 != __last1)
5473    {
5474        if (__first2 == __last2)
5475            return _VSTD::copy(__first1, __last1, __result);
5476        if (__comp(*__first1, *__first2))
5477        {
5478            *__result = *__first1;
5479            ++__result;
5480            ++__first1;
5481        }
5482        else
5483        {
5484            if (!__comp(*__first2, *__first1))
5485                ++__first1;
5486            ++__first2;
5487        }
5488    }
5489    return __result;
5490}
5491
5492template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5493inline _LIBCPP_INLINE_VISIBILITY
5494_OutputIterator
5495set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5496               _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5497{
5498#ifdef _LIBCPP_DEBUG
5499    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5500    __debug_less<_Compare> __c(__comp);
5501    return __set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5502#else  // _LIBCPP_DEBUG
5503    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5504    return __set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5505#endif  // _LIBCPP_DEBUG
5506}
5507
5508template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5509inline _LIBCPP_INLINE_VISIBILITY
5510_OutputIterator
5511set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5512               _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5513{
5514    return _VSTD::set_difference(__first1, __last1, __first2, __last2, __result,
5515                                __less<typename iterator_traits<_InputIterator1>::value_type,
5516                                       typename iterator_traits<_InputIterator2>::value_type>());
5517}
5518
5519// set_symmetric_difference
5520
5521template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
5522_OutputIterator
5523__set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5524                           _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5525{
5526    while (__first1 != __last1)
5527    {
5528        if (__first2 == __last2)
5529            return _VSTD::copy(__first1, __last1, __result);
5530        if (__comp(*__first1, *__first2))
5531        {
5532            *__result = *__first1;
5533            ++__result;
5534            ++__first1;
5535        }
5536        else
5537        {
5538            if (__comp(*__first2, *__first1))
5539            {
5540                *__result = *__first2;
5541                ++__result;
5542            }
5543            else
5544                ++__first1;
5545            ++__first2;
5546        }
5547    }
5548    return _VSTD::copy(__first2, __last2, __result);
5549}
5550
5551template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
5552inline _LIBCPP_INLINE_VISIBILITY
5553_OutputIterator
5554set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5555                         _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
5556{
5557#ifdef _LIBCPP_DEBUG
5558    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5559    __debug_less<_Compare> __c(__comp);
5560    return __set_symmetric_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __c);
5561#else  // _LIBCPP_DEBUG
5562    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5563    return __set_symmetric_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
5564#endif  // _LIBCPP_DEBUG
5565}
5566
5567template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
5568inline _LIBCPP_INLINE_VISIBILITY
5569_OutputIterator
5570set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,
5571                         _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
5572{
5573    return _VSTD::set_symmetric_difference(__first1, __last1, __first2, __last2, __result,
5574                                          __less<typename iterator_traits<_InputIterator1>::value_type,
5575                                                 typename iterator_traits<_InputIterator2>::value_type>());
5576}
5577
5578// lexicographical_compare
5579
5580template <class _Compare, class _InputIterator1, class _InputIterator2>
5581bool
5582__lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
5583                          _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
5584{
5585    for (; __first2 != __last2; ++__first1, (void) ++__first2)
5586    {
5587        if (__first1 == __last1 || __comp(*__first1, *__first2))
5588            return true;
5589        if (__comp(*__first2, *__first1))
5590            return false;
5591    }
5592    return false;
5593}
5594
5595template <class _InputIterator1, class _InputIterator2, class _Compare>
5596inline _LIBCPP_INLINE_VISIBILITY
5597bool
5598lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
5599                        _InputIterator2 __first2, _InputIterator2 __last2, _Compare __comp)
5600{
5601#ifdef _LIBCPP_DEBUG
5602    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5603    __debug_less<_Compare> __c(__comp);
5604    return __lexicographical_compare<_Comp_ref>(__first1, __last1, __first2, __last2, __c);
5605#else  // _LIBCPP_DEBUG
5606    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5607    return __lexicographical_compare<_Comp_ref>(__first1, __last1, __first2, __last2, __comp);
5608#endif  // _LIBCPP_DEBUG
5609}
5610
5611template <class _InputIterator1, class _InputIterator2>
5612inline _LIBCPP_INLINE_VISIBILITY
5613bool
5614lexicographical_compare(_InputIterator1 __first1, _InputIterator1 __last1,
5615                        _InputIterator2 __first2, _InputIterator2 __last2)
5616{
5617    return _VSTD::lexicographical_compare(__first1, __last1, __first2, __last2,
5618                                         __less<typename iterator_traits<_InputIterator1>::value_type,
5619                                                typename iterator_traits<_InputIterator2>::value_type>());
5620}
5621
5622// next_permutation
5623
5624template <class _Compare, class _BidirectionalIterator>
5625bool
5626__next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5627{
5628    _BidirectionalIterator __i = __last;
5629    if (__first == __last || __first == --__i)
5630        return false;
5631    while (true)
5632    {
5633        _BidirectionalIterator __ip1 = __i;
5634        if (__comp(*--__i, *__ip1))
5635        {
5636            _BidirectionalIterator __j = __last;
5637            while (!__comp(*__i, *--__j))
5638                ;
5639            swap(*__i, *__j);
5640            _VSTD::reverse(__ip1, __last);
5641            return true;
5642        }
5643        if (__i == __first)
5644        {
5645            _VSTD::reverse(__first, __last);
5646            return false;
5647        }
5648    }
5649}
5650
5651template <class _BidirectionalIterator, class _Compare>
5652inline _LIBCPP_INLINE_VISIBILITY
5653bool
5654next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5655{
5656#ifdef _LIBCPP_DEBUG
5657    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5658    __debug_less<_Compare> __c(__comp);
5659    return __next_permutation<_Comp_ref>(__first, __last, __c);
5660#else  // _LIBCPP_DEBUG
5661    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5662    return __next_permutation<_Comp_ref>(__first, __last, __comp);
5663#endif  // _LIBCPP_DEBUG
5664}
5665
5666template <class _BidirectionalIterator>
5667inline _LIBCPP_INLINE_VISIBILITY
5668bool
5669next_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
5670{
5671    return _VSTD::next_permutation(__first, __last,
5672                                  __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
5673}
5674
5675// prev_permutation
5676
5677template <class _Compare, class _BidirectionalIterator>
5678bool
5679__prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5680{
5681    _BidirectionalIterator __i = __last;
5682    if (__first == __last || __first == --__i)
5683        return false;
5684    while (true)
5685    {
5686        _BidirectionalIterator __ip1 = __i;
5687        if (__comp(*__ip1, *--__i))
5688        {
5689            _BidirectionalIterator __j = __last;
5690            while (!__comp(*--__j, *__i))
5691                ;
5692            swap(*__i, *__j);
5693            _VSTD::reverse(__ip1, __last);
5694            return true;
5695        }
5696        if (__i == __first)
5697        {
5698            _VSTD::reverse(__first, __last);
5699            return false;
5700        }
5701    }
5702}
5703
5704template <class _BidirectionalIterator, class _Compare>
5705inline _LIBCPP_INLINE_VISIBILITY
5706bool
5707prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp)
5708{
5709#ifdef _LIBCPP_DEBUG
5710    typedef typename add_lvalue_reference<__debug_less<_Compare> >::type _Comp_ref;
5711    __debug_less<_Compare> __c(__comp);
5712    return __prev_permutation<_Comp_ref>(__first, __last, __c);
5713#else  // _LIBCPP_DEBUG
5714    typedef typename add_lvalue_reference<_Compare>::type _Comp_ref;
5715    return __prev_permutation<_Comp_ref>(__first, __last, __comp);
5716#endif  // _LIBCPP_DEBUG
5717}
5718
5719template <class _BidirectionalIterator>
5720inline _LIBCPP_INLINE_VISIBILITY
5721bool
5722prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last)
5723{
5724    return _VSTD::prev_permutation(__first, __last,
5725                                  __less<typename iterator_traits<_BidirectionalIterator>::value_type>());
5726}
5727
5728template <class _Tp>
5729inline _LIBCPP_INLINE_VISIBILITY
5730typename enable_if
5731<
5732    is_integral<_Tp>::value,
5733    _Tp
5734>::type
5735__rotate_left(_Tp __t, _Tp __n = 1)
5736{
5737    const unsigned __bits = static_cast<unsigned>(sizeof(_Tp) * __CHAR_BIT__ - 1);
5738    __n &= __bits;
5739    return static_cast<_Tp>((__t << __n) | (static_cast<typename make_unsigned<_Tp>::type>(__t) >> (__bits - __n)));
5740}
5741
5742template <class _Tp>
5743inline _LIBCPP_INLINE_VISIBILITY
5744typename enable_if
5745<
5746    is_integral<_Tp>::value,
5747    _Tp
5748>::type
5749__rotate_right(_Tp __t, _Tp __n = 1)
5750{
5751    const unsigned __bits = static_cast<unsigned>(sizeof(_Tp) * __CHAR_BIT__ - 1);
5752    __n &= __bits;
5753    return static_cast<_Tp>((__t << (__bits - __n)) | (static_cast<typename make_unsigned<_Tp>::type>(__t) >> __n));
5754}
5755
5756_LIBCPP_END_NAMESPACE_STD
5757
5758#endif  // _LIBCPP_ALGORITHM
5759