Sprout/sprout/algorithm/fixed/nth_element.hpp
2019-01-07 17:47:17 +09:00

81 lines
3.2 KiB
C++

/*=============================================================================
Copyright (c) 2011-2019 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_FIXED_NTH_ELEMENT_HPP
#define SPROUT_ALGORITHM_FIXED_NTH_ELEMENT_HPP
#include <sprout/config.hpp>
#include <sprout/container/traits.hpp>
#include <sprout/container/functions.hpp>
#include <sprout/iterator/operation.hpp>
#include <sprout/algorithm/fixed/results.hpp>
#include <sprout/algorithm/fixed/swap_element.hpp>
#include <sprout/algorithm/fixed/make_partial_heap.hpp>
#include HDR_FUNCTIONAL_SSCRISK_CEL_OR_SPROUT
namespace sprout {
namespace fixed {
namespace detail {
template<typename Container>
inline SPROUT_CONSTEXPR typename sprout::fixed::results::algorithm<Container>::type
nth_element_impl_1(
Container const& cont,
typename sprout::container_traits<Container>::difference_type offset,
typename sprout::container_traits<Container>::difference_type nth_size
)
{
return sprout::fixed::swap_element(
cont,
sprout::next(sprout::internal_begin(cont), offset),
sprout::next(sprout::internal_begin(cont), offset + nth_size)
);
}
template<typename Container, typename Compare>
inline SPROUT_CONSTEXPR typename sprout::fixed::results::algorithm<Container>::type
nth_element_impl(
Container const& cont, Compare comp,
typename sprout::container_traits<Container>::difference_type offset,
typename sprout::container_traits<Container>::difference_type size,
typename sprout::container_traits<Container>::difference_type nth_size
)
{
return sprout::fixed::detail::nth_element_impl_1(
sprout::fixed::detail::make_partial_heap_impl(cont, comp, offset, size, nth_size + 1),
offset,
nth_size
);
}
} // namespace detail
//
// nth_element
//
template<typename Container, typename Compare>
inline SPROUT_CONSTEXPR typename sprout::fixed::results::algorithm<Container>::type
nth_element(Container const& cont, typename sprout::container_traits<Container>::const_iterator nth, Compare comp) {
return sprout::fixed::detail::nth_element_impl(
cont, comp,
sprout::internal_begin_offset(cont),
sprout::size(cont),
sprout::distance(sprout::begin(cont), nth)
);
}
template<typename Container>
inline SPROUT_CONSTEXPR typename sprout::fixed::results::algorithm<Container>::type
nth_element(Container const& cont, typename sprout::container_traits<Container>::const_iterator nth) {
return sprout::fixed::detail::nth_element_impl(
cont, NS_SSCRISK_CEL_OR_SPROUT::less<typename sprout::container_traits<Container>::value_type>(),
sprout::internal_begin_offset(cont),
sprout::size(cont),
sprout::distance(sprout::begin(cont), nth)
);
}
} // namespace fixed
using sprout::fixed::nth_element;
} // namespace sprout
#endif // #ifndef SPROUT_ALGORITHM_FIXED_NTH_ELEMENT_HPP