Sprout/sprout/algorithm/binary_search.hpp
2015-01-10 19:13:57 +09:00

43 lines
1.6 KiB
C++

/*=============================================================================
Copyright (c) 2011-2015 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_BINARY_SEARCH_HPP
#define SPROUT_ALGORITHM_BINARY_SEARCH_HPP
#include <iterator>
#include <sprout/config.hpp>
#include <sprout/algorithm/lower_bound.hpp>
#include <sprout/functional/less.hpp>
namespace sprout {
namespace detail {
template<typename ForwardIterator, typename T, typename Compare>
inline SPROUT_CONSTEXPR bool
binary_search_impl(ForwardIterator first, ForwardIterator last, T const& value, Compare comp) {
return (first != last && !comp(value, *first));
}
} // namespace detail
// 25.4.3.4 binary_search
//
// recursion depth:
// O(log N)
//
template<typename ForwardIterator, typename T, typename Compare>
inline SPROUT_CONSTEXPR bool
binary_search(ForwardIterator first, ForwardIterator last, T const& value, Compare comp) {
return sprout::detail::binary_search_impl(sprout::lower_bound(first, last, value, comp), last, value, comp);
}
template<typename ForwardIterator, typename T>
inline SPROUT_CONSTEXPR bool
binary_search(ForwardIterator first, ForwardIterator last, T const& value) {
return sprout::binary_search(first, last, value, sprout::less<>());
}
} // namespace sprout
#endif // #ifndef SPROUT_ALGORITHM_BINARY_SEARCH_HPP