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1// -*- C++ -*-2//===----------------------------------------------------------------------===//3//4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.5// See https://llvm.org/LICENSE.txt for license information.6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception7//8//===----------------------------------------------------------------------===//9 10#ifndef _LIBCPP___ALGORITHM_IS_PERMUTATION_H11#define _LIBCPP___ALGORITHM_IS_PERMUTATION_H12 13#include <__algorithm/comp.h>14#include <__algorithm/iterator_operations.h>15#include <__config>16#include <__functional/identity.h>17#include <__iterator/concepts.h>18#include <__iterator/distance.h>19#include <__iterator/iterator_traits.h>20#include <__type_traits/enable_if.h>21#include <__type_traits/invoke.h>22#include <__type_traits/is_callable.h>23#include <__type_traits/is_same.h>24#include <__utility/move.h>25 26#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)27# pragma GCC system_header28#endif29 30_LIBCPP_PUSH_MACROS31#include <__undef_macros>32 33_LIBCPP_BEGIN_NAMESPACE_STD34 35template <class _Iter1, class _Sent1, class _Iter2, class _Sent2, class = void>36struct _ConstTimeDistance : false_type {};37 38#if _LIBCPP_STD_VER >= 2039 40template <class _Iter1, class _Sent1, class _Iter2, class _Sent2>41struct _ConstTimeDistance<_Iter1,42 _Sent1,43 _Iter2,44 _Sent2,45 __enable_if_t< sized_sentinel_for<_Sent1, _Iter1> && sized_sentinel_for<_Sent2, _Iter2> >>46 : true_type {};47 48#else49 50template <class _Iter1, class _Iter2>51struct _ConstTimeDistance<52 _Iter1,53 _Iter1,54 _Iter2,55 _Iter2,56 __enable_if_t< is_same<typename iterator_traits<_Iter1>::iterator_category, random_access_iterator_tag>::value &&57 is_same<typename iterator_traits<_Iter2>::iterator_category, random_access_iterator_tag>::value > >58 : true_type {};59 60#endif // _LIBCPP_STD_VER >= 2061 62// Internal functions63 64// For each element in [f1, l1) see if there are the same number of equal elements in [f2, l2)65template <class _AlgPolicy,66 class _Iter1,67 class _Sent1,68 class _Iter2,69 class _Sent2,70 class _Proj1,71 class _Proj2,72 class _Pred>73_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __is_permutation_impl(74 _Iter1 __first1,75 _Sent1 __last1,76 _Iter2 __first2,77 _Sent2 __last2,78 _Pred&& __pred,79 _Proj1&& __proj1,80 _Proj2&& __proj2) {81 using _D1 = __iterator_difference_type<_Iter1>;82 83 for (auto __i = __first1; __i != __last1; ++__i) {84 // Have we already counted the number of *__i in [f1, l1)?85 auto __match = __first1;86 for (; __match != __i; ++__match) {87 if (std::__invoke(__pred, std::__invoke(__proj1, *__match), std::__invoke(__proj1, *__i)))88 break;89 }90 91 if (__match == __i) {92 // Count number of *__i in [f2, l2)93 _D1 __c2 = 0;94 for (auto __j = __first2; __j != __last2; ++__j) {95 if (std::__invoke(__pred, std::__invoke(__proj1, *__i), std::__invoke(__proj2, *__j)))96 ++__c2;97 }98 if (__c2 == 0)99 return false;100 101 // Count number of *__i in [__i, l1) (we can start with 1)102 _D1 __c1 = 1;103 for (auto __j = _IterOps<_AlgPolicy>::next(__i); __j != __last1; ++__j) {104 if (std::__invoke(__pred, std::__invoke(__proj1, *__i), std::__invoke(__proj1, *__j)))105 ++__c1;106 }107 if (__c1 != __c2)108 return false;109 }110 }111 112 return true;113}114 115// 2+1 iterators, predicate. Not used by range algorithms.116template <class _AlgPolicy, class _ForwardIterator1, class _Sentinel1, class _ForwardIterator2, class _BinaryPredicate>117[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __is_permutation(118 _ForwardIterator1 __first1, _Sentinel1 __last1, _ForwardIterator2 __first2, _BinaryPredicate&& __pred) {119 // Shorten sequences as much as possible by lopping of any equal prefix.120 for (; __first1 != __last1; ++__first1, (void)++__first2) {121 if (!__pred(*__first1, *__first2))122 break;123 }124 125 if (__first1 == __last1)126 return true;127 128 // __first1 != __last1 && *__first1 != *__first2129 using _D1 = __iterator_difference_type<_ForwardIterator1>;130 _D1 __l1 = _IterOps<_AlgPolicy>::distance(__first1, __last1);131 if (__l1 == _D1(1))132 return false;133 auto __last2 = _IterOps<_AlgPolicy>::next(__first2, __l1);134 135 return std::__is_permutation_impl<_AlgPolicy>(136 std::move(__first1),137 std::move(__last1),138 std::move(__first2),139 std::move(__last2),140 __pred,141 __identity(),142 __identity());143}144 145// 2+2 iterators, predicate, non-constant time `distance`.146template <class _AlgPolicy,147 class _Iter1,148 class _Sent1,149 class _Iter2,150 class _Sent2,151 class _Proj1,152 class _Proj2,153 class _Pred>154_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __is_permutation(155 _Iter1 __first1,156 _Sent1 __last1,157 _Iter2 __first2,158 _Sent2 __last2,159 _Pred&& __pred,160 _Proj1&& __proj1,161 _Proj2&& __proj2,162 /*_ConstTimeDistance=*/false_type) {163 // Shorten sequences as much as possible by lopping of any equal prefix.164 while (__first1 != __last1 && __first2 != __last2) {165 if (!std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))166 break;167 ++__first1;168 ++__first2;169 }170 171 if (__first1 == __last1)172 return __first2 == __last2;173 if (__first2 == __last2) // Second range is shorter174 return false;175 176 using _D1 = __iterator_difference_type<_Iter1>;177 _D1 __l1 = _IterOps<_AlgPolicy>::distance(__first1, __last1);178 179 using _D2 = __iterator_difference_type<_Iter2>;180 _D2 __l2 = _IterOps<_AlgPolicy>::distance(__first2, __last2);181 if (__l1 != __l2)182 return false;183 184 return std::__is_permutation_impl<_AlgPolicy>(185 std::move(__first1), std::move(__last1), std::move(__first2), std::move(__last2), __pred, __proj1, __proj2);186}187 188// 2+2 iterators, predicate, specialization for constant-time `distance` call.189template <class _AlgPolicy,190 class _Iter1,191 class _Sent1,192 class _Iter2,193 class _Sent2,194 class _Proj1,195 class _Proj2,196 class _Pred>197_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __is_permutation(198 _Iter1 __first1,199 _Sent1 __last1,200 _Iter2 __first2,201 _Sent2 __last2,202 _Pred&& __pred,203 _Proj1&& __proj1,204 _Proj2&& __proj2,205 /*_ConstTimeDistance=*/true_type) {206 if (std::distance(__first1, __last1) != std::distance(__first2, __last2))207 return false;208 return std::__is_permutation<_AlgPolicy>(209 std::move(__first1),210 std::move(__last1),211 std::move(__first2),212 std::move(__last2),213 __pred,214 __proj1,215 __proj2,216 /*_ConstTimeDistance=*/false_type());217}218 219// 2+2 iterators, predicate220template <class _AlgPolicy,221 class _Iter1,222 class _Sent1,223 class _Iter2,224 class _Sent2,225 class _Proj1,226 class _Proj2,227 class _Pred>228_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool __is_permutation(229 _Iter1 __first1,230 _Sent1 __last1,231 _Iter2 __first2,232 _Sent2 __last2,233 _Pred&& __pred,234 _Proj1&& __proj1,235 _Proj2&& __proj2) {236 return std::__is_permutation<_AlgPolicy>(237 std::move(__first1),238 std::move(__last1),239 std::move(__first2),240 std::move(__last2),241 __pred,242 __proj1,243 __proj2,244 _ConstTimeDistance<_Iter1, _Sent1, _Iter2, _Sent2>());245}246 247// Public interface248 249// 2+1 iterators, predicate250template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>251[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool is_permutation(252 _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _BinaryPredicate __pred) {253 static_assert(__is_callable<_BinaryPredicate&, decltype(*__first1), decltype(*__first2)>::value,254 "The comparator has to be callable");255 256 return std::__is_permutation<_ClassicAlgPolicy>(std::move(__first1), std::move(__last1), std::move(__first2), __pred);257}258 259// 2+1 iterators260template <class _ForwardIterator1, class _ForwardIterator2>261[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool262is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2) {263 return std::is_permutation(__first1, __last1, __first2, __equal_to());264}265 266#if _LIBCPP_STD_VER >= 14267 268// 2+2 iterators269template <class _ForwardIterator1, class _ForwardIterator2>270[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool is_permutation(271 _ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) {272 return std::__is_permutation<_ClassicAlgPolicy>(273 std::move(__first1),274 std::move(__last1),275 std::move(__first2),276 std::move(__last2),277 __equal_to(),278 __identity(),279 __identity());280}281 282// 2+2 iterators, predicate283template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>284[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool is_permutation(285 _ForwardIterator1 __first1,286 _ForwardIterator1 __last1,287 _ForwardIterator2 __first2,288 _ForwardIterator2 __last2,289 _BinaryPredicate __pred) {290 static_assert(__is_callable<_BinaryPredicate&, decltype(*__first1), decltype(*__first2)>::value,291 "The comparator has to be callable");292 293 return std::__is_permutation<_ClassicAlgPolicy>(294 std::move(__first1),295 std::move(__last1),296 std::move(__first2),297 std::move(__last2),298 __pred,299 __identity(),300 __identity());301}302 303#endif // _LIBCPP_STD_VER >= 14304 305_LIBCPP_END_NAMESPACE_STD306 307_LIBCPP_POP_MACROS308 309#endif // _LIBCPP___ALGORITHM_IS_PERMUTATION_H310