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64 lines
2.2 KiB
C++
64 lines
2.2 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2017 Bolero MURAKAMI
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https://github.com/bolero-MURAKAMI/Sprout
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#ifndef SPROUT_ALGORITHM_CXX14_PREV_PERMUTATION_HPP
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#define SPROUT_ALGORITHM_CXX14_PREV_PERMUTATION_HPP
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#include <iterator>
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#include <type_traits>
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#include <sprout/config.hpp>
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#include <sprout/algorithm/cxx14/reverse.hpp>
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#include <sprout/utility/swap.hpp>
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#include HDR_FUNCTIONAL_SSCRISK_CEL_OR_SPROUT
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namespace sprout {
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namespace detail {
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template<typename Compare, typename BidirectionalIterator>
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inline SPROUT_CXX14_CONSTEXPR bool
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prev_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp) {
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BidirectionalIterator i = last;
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if (first == last || first == --i) {
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return false;
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}
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while (true) {
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BidirectionalIterator ip1 = i;
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if (comp(*ip1, *--i)) {
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BidirectionalIterator j = last;
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while (!comp(*--j, *i))
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;
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sprout::swap(*i, *j);
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sprout::reverse(ip1, last);
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return true;
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}
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if (i == first) {
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sprout::reverse(first, last);
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return false;
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}
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}
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}
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} // namespace detail
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//
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// 25.4.9 Permutation generators
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//
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template<typename BidirectionalIterator, typename Compare>
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inline SPROUT_CXX14_CONSTEXPR bool
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prev_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp) {
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typedef typename std::add_lvalue_reference<Compare>::type compare_ref;
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return sprout::detail::prev_permutation<compare_ref>(first, last, comp);
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}
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template<typename BidirectionalIterator>
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inline SPROUT_CXX14_CONSTEXPR bool
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prev_permutation(BidirectionalIterator first, BidirectionalIterator last) {
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return sprout::prev_permutation(
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first, last,
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NS_SSCRISK_CEL_OR_SPROUT::less<typename std::iterator_traits<BidirectionalIterator>::value_type>()
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);
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}
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} // namespace sprout
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#endif // #ifndef SPROUT_ALGORITHM_CXX14_PREV_PERMUTATION_HPP
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