| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP___ALGORITHM_PREV_PERMUTATION_H |
| #define _LIBCPP___ALGORITHM_PREV_PERMUTATION_H |
| |
| #include <__config> |
| #include <__algorithm/comp.h> |
| #include <__algorithm/comp_ref_type.h> |
| #include <__algorithm/reverse.h> |
| #include <__iterator/iterator_traits.h> |
| #include <__utility/swap.h> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| #pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| template <class _Compare, class _BidirectionalIterator> |
| _LIBCPP_CONSTEXPR_AFTER_CXX17 bool |
| __prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp) |
| { |
| _BidirectionalIterator __i = __last; |
| if (__first == __last || __first == --__i) |
| return false; |
| while (true) |
| { |
| _BidirectionalIterator __ip1 = __i; |
| if (__comp(*__ip1, *--__i)) |
| { |
| _BidirectionalIterator __j = __last; |
| while (!__comp(*--__j, *__i)) |
| ; |
| swap(*__i, *__j); |
| _VSTD::reverse(__ip1, __last); |
| return true; |
| } |
| if (__i == __first) |
| { |
| _VSTD::reverse(__first, __last); |
| return false; |
| } |
| } |
| } |
| |
| template <class _BidirectionalIterator, class _Compare> |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 |
| bool |
| prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last, _Compare __comp) |
| { |
| typedef typename __comp_ref_type<_Compare>::type _Comp_ref; |
| return _VSTD::__prev_permutation<_Comp_ref>(__first, __last, __comp); |
| } |
| |
| template <class _BidirectionalIterator> |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 |
| bool |
| prev_permutation(_BidirectionalIterator __first, _BidirectionalIterator __last) |
| { |
| return _VSTD::prev_permutation(__first, __last, |
| __less<typename iterator_traits<_BidirectionalIterator>::value_type>()); |
| } |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___ALGORITHM_PREV_PERMUTATION_H |