Sprout/sprout/algorithm/fixed/nth_element.hpp
2011-10-02 00:19:13 +09:00

86 lines
3 KiB
C++

#ifndef SPROUT_ALGORITHM_FIXED_NTH_ELEMENT_HPP
#define SPROUT_ALGORITHM_FIXED_NTH_ELEMENT_HPP
#include <sprout/config.hpp>
#include <sprout/fixed_container/traits.hpp>
#include <sprout/fixed_container/functions.hpp>
#include <sprout/iterator/operation.hpp>
#include <sprout/algorithm/fixed/result_of.hpp>
#include <sprout/algorithm/fixed/swap_element.hpp>
#include <sprout/algorithm/fixed/make_partial_heap.hpp>
#include HDR_FUNCTIONAL_SSCRISK_CEL_OR_SPROUT_DETAIL
#include HDR_ITERATOR_SSCRISK_CEL_OR_SPROUT_DETAIL
namespace sprout {
namespace fixed {
namespace detail {
template<typename Container>
SPROUT_CONSTEXPR inline typename sprout::fixed::result_of::algorithm<Container>::type nth_element_impl_1(
Container const& cont,
typename sprout::fixed_container_traits<Container>::difference_type offset,
typename sprout::fixed_container_traits<Container>::difference_type nth_size
)
{
return sprout::fixed::swap_element(
cont,
sprout::next(sprout::fixed_begin(cont), offset),
sprout::next(sprout::fixed_begin(cont), offset + nth_size)
);
}
template<typename Container, typename Compare>
SPROUT_CONSTEXPR inline typename sprout::fixed::result_of::algorithm<Container>::type nth_element_impl(
Container const& cont,
Compare comp,
typename sprout::fixed_container_traits<Container>::difference_type offset,
typename sprout::fixed_container_traits<Container>::difference_type size,
typename sprout::fixed_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>
SPROUT_CONSTEXPR inline typename sprout::fixed::result_of::algorithm<Container>::type nth_element(
Container const& cont,
typename sprout::fixed_container_traits<Container>::const_iterator nth,
Compare comp
)
{
return sprout::fixed::detail::nth_element_impl(
cont,
comp,
sprout::fixed_begin_offset(cont),
sprout::size(cont),
NS_SSCRISK_CEL_OR_SPROUT_DETAIL::distance(sprout::begin(cont), nth)
);
}
//
// nth_element
//
template<typename Container>
SPROUT_CONSTEXPR inline typename sprout::fixed::result_of::algorithm<Container>::type nth_element(
Container const& cont,
typename sprout::fixed_container_traits<Container>::const_iterator nth
)
{
return sprout::fixed::detail::nth_element_impl(
cont,
NS_SSCRISK_CEL_OR_SPROUT_DETAIL::less<typename sprout::fixed_container_traits<Container>::value_type>(),
sprout::fixed_begin_offset(cont),
sprout::size(cont),
NS_SSCRISK_CEL_OR_SPROUT_DETAIL::distance(sprout::begin(cont), nth)
);
}
} // namespace fixed
using sprout::fixed::nth_element;
} // namespace sprout
#endif // #ifndef SPROUT_ALGORITHM_FIXED_NTH_ELEMENT_HPP