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Sprout/sprout/algorithm/cxx14/stable_partition.hpp
2016-02-25 18:48:28 +09:00

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2.2 KiB
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/*=============================================================================
Copyright (c) 2011-2016 Bolero MURAKAMI
https://github.com/bolero-MURAKAMI/Sprout
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/
#ifndef SPROUT_ALGORITHM_CXX14_STABLE_PARTITION_HPP
#define SPROUT_ALGORITHM_CXX14_STABLE_PARTITION_HPP
#include <sprout/config.hpp>
#include <sprout/iterator/distance.hpp>
#include <sprout/iterator/next.hpp>
#include <sprout/iterator/advance.hpp>
#include <sprout/algorithm/find_if_not.hpp>
#include <sprout/algorithm/cxx14/rotate.hpp>
namespace sprout {
namespace detail {
template<typename BidirectionalIterator, typename Predicate, typename Distance>
inline SPROUT_CXX14_CONSTEXPR BidirectionalIterator
inplace_stable_partition(BidirectionalIterator first, Predicate pred, Distance len) {
if (len == 1) {
return first;
}
BidirectionalIterator middle = first;
sprout::advance(middle, len / 2);
BidirectionalIterator left_split = sprout::detail::inplace_stable_partition(first, pred, len / 2);
Distance right_len = len - len / 2;
BidirectionalIterator right_split = sprout::find_if_not(middle, sprout::next(middle, right_len), pred);
if (right_len) {
right_split = sprout::detail::inplace_stable_partition(middle, pred, right_len);
}
sprout::rotate(left_split, middle, right_split);
sprout::advance(left_split, sprout::distance(middle, right_split));
return left_split;
}
} // namespace sprout
//
// 25.3.13 Partitions
//
template<typename BidirectionalIterator, typename Predicate>
inline SPROUT_CXX14_CONSTEXPR BidirectionalIterator
stable_partition(BidirectionalIterator first, BidirectionalIterator last, Predicate pred) {
first = sprout::find_if_not(first, last, pred);
return first == last ? first
: sprout::detail::inplace_stable_partition(first, pred, sprout::distance(first, last))
;
}
} // namespace sprout
#endif // #ifndef SPROUT_ALGORITHM_CXX14_STABLE_PARTITION_HPP