Sprout/sprout/algorithm/binary_search.hpp
2012-04-03 21:58:23 +09:00

37 lines
1.8 KiB
C++

#ifndef SPROUT_ALGORITHM_BINARY_SEARCH_HPP
#define SPROUT_ALGORITHM_BINARY_SEARCH_HPP
#include <sprout/config.hpp>
#include <sprout/iterator/operation.hpp>
#include HDR_ITERATOR_SSCRISK_CEL_OR_SPROUT
namespace sprout {
// Copyright (C) 2011 RiSK (sscrisk)
// 25.4.3.4 binary_search
template<typename ForwardIterator, typename T>
SPROUT_CONSTEXPR bool binary_search(ForwardIterator first, ForwardIterator last, T const& value) {
return first == last ? false
: sprout::next(first) == last ? !(*first < value) && !(value < *first) ? true : false
: *sprout::next(first, NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) / 2) < value
? sprout::binary_search(sprout::next(first, NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) / 2), last, value)
: value < *sprout::next(first, NS_SSCRISK_CEL_OR_SPROUT::distance(first, last)) / 2
? sprout::binary_search(first, sprout::next(first, NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) / 2), value)
: true
;
}
template<typename ForwardIterator, typename T, typename Compare>
SPROUT_CONSTEXPR bool binary_search(ForwardIterator first, ForwardIterator last, T const& value, Compare comp) {
return first == last ? false
: sprout::next(first) == last ? !comp(*first, value) && !comp(value, *first) ? true : false
: comp(*sprout::next(first, NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) / 2), value)
? sprout::binary_search(sprout::next(first, NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) / 2), last, value)
: comp(value, *sprout::next(first, NS_SSCRISK_CEL_OR_SPROUT::distance(first, last)) / 2)
? sprout::binary_search(first, sprout::next(first, NS_SSCRISK_CEL_OR_SPROUT::distance(first, last) / 2), value)
: true
;
}
} // namespace sprout
#endif // #ifndef SPROUT_ALGORITHM_BINARY_SEARCH_HPP