Sprout/sprout/algorithm/lower_bound.hpp
2013-01-11 03:17:06 +09:00

38 lines
1.3 KiB
C++

#ifndef SPROUT_ALGORITHM_LOWER_BOUND_HPP
#define SPROUT_ALGORITHM_LOWER_BOUND_HPP
#include <iterator>
#include <sprout/config.hpp>
#include <sprout/iterator/operation.hpp>
#include HDR_FUNCTIONAL_SSCRISK_CEL_OR_SPROUT
namespace sprout {
// Copyright (C) 2011 RiSK (sscrisk)
// 25.4.3.1 lower_bound
//
// recursion depth:
// O(log N)
//
template<typename ForwardIterator, typename T, typename Compare>
inline SPROUT_CONSTEXPR ForwardIterator
lower_bound(ForwardIterator first, ForwardIterator last, T const& value, Compare comp) {
return first == last ? last
: sprout::next(first) == last ? comp(*first, value) ? last : first
: comp(*sprout::next(first, sprout::distance(first, last) / 2), value)
? sprout::lower_bound(sprout::next(first, sprout::distance(first, last) / 2), last, value, comp)
: sprout::lower_bound(first, sprout::next(first, sprout::distance(first, last) / 2), value, comp)
;
}
template<typename ForwardIterator, typename T>
inline SPROUT_CONSTEXPR ForwardIterator
lower_bound(ForwardIterator first, ForwardIterator last, T const& value) {
return sprout::lower_bound(
first, last, value,
NS_SSCRISK_CEL_OR_SPROUT::less<typename std::iterator_traits<ForwardIterator>::value_type>()
);
}
} // namespace sprout
#endif // #ifndef SPROUT_ALGORITHM_LOWER_BOUND_HPP