mirror of
https://github.com/bolero-MURAKAMI/Sprout
synced 2024-11-12 21:09:01 +00:00
86 lines
3.3 KiB
C++
86 lines
3.3 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2016 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_INPLACE_MERGE_HPP
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#define SPROUT_ALGORITHM_CXX14_INPLACE_MERGE_HPP
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#include <iterator>
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#include <sprout/config.hpp>
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#include <sprout/iterator/distance.hpp>
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#include <sprout/iterator/advance.hpp>
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#include <sprout/algorithm/lower_bound.hpp>
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#include <sprout/algorithm/upper_bound.hpp>
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#include <sprout/algorithm/cxx14/iter_swap.hpp>
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#include <sprout/algorithm/cxx14/rotate.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 BidirectionalIterator, typename Distance, typename Compare>
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inline SPROUT_CXX14_CONSTEXPR void
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inplace_merge(
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BidirectionalIterator first, BidirectionalIterator middle, BidirectionalIterator last,
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Distance len1, Distance len2, Compare comp
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)
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{
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if (len1 == 0 || len2 == 0) {
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return;
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}
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if (len1 + len2 == 2) {
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if (comp(*middle, *first)) {
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sprout::iter_swap(first, middle);
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}
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return;
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}
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BidirectionalIterator first_cut = first;
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BidirectionalIterator second_cut = middle;
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Distance len11 = 0;
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Distance len22 = 0;
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if (len1 > len2) {
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len11 = len1 / 2;
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sprout::advance(first_cut, len11);
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second_cut = sprout::lower_bound(middle, last, *first_cut, comp);
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len22 = sprout::distance(middle, second_cut);
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} else {
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len22 = len2 / 2;
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sprout::advance(second_cut, len22);
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first_cut = sprout::upper_bound(first, middle, *second_cut, comp);
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len11 = sprout::distance(first, first_cut);
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}
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sprout::rotate(first_cut, middle, second_cut);
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BidirectionalIterator new_middle = first_cut;
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sprout::advance(new_middle, sprout::distance(middle, second_cut));
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sprout::detail::inplace_merge(first, first_cut, new_middle, len11, len22, comp);
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sprout::detail::inplace_merge(new_middle, second_cut, last, len1 - len11, len2 - len22, comp);
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}
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} // namespace detail
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//
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// 25.4.4 Merge
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//
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template<typename BidirectionalIterator, typename Compare>
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inline SPROUT_CXX14_CONSTEXPR void
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inplace_merge(BidirectionalIterator first, BidirectionalIterator middle, BidirectionalIterator last, Compare comp) {
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typedef typename std::iterator_traits<BidirectionalIterator>::difference_type difference_type;
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if (first == middle || middle == last) {
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return;
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}
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difference_type const len1 = sprout::distance(first, middle);
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difference_type const len2 = sprout::distance(middle, last);
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sprout::detail::inplace_merge(first, middle, last, len1, len2, comp);
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}
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template<typename BidirectionalIterator>
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inline SPROUT_CXX14_CONSTEXPR void
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inplace_merge(BidirectionalIterator first, BidirectionalIterator middle, BidirectionalIterator last) {
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sprout::inplace_merge(
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first, middle, 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_INPLACE_MERGE_HPP
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