Sprout/sprout/algorithm/cxx14/next_permutation.hpp
2015-01-10 19:13:57 +09:00

64 lines
2.2 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_CXX14_NEXT_PERMUTATION_HPP
#define SPROUT_ALGORITHM_CXX14_NEXT_PERMUTATION_HPP
#include <iterator>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/algorithm/cxx14/reverse.hpp>
#include <sprout/utility/swap.hpp>
#include HDR_FUNCTIONAL_SSCRISK_CEL_OR_SPROUT
namespace sprout {
namespace detail {
template<typename Compare, typename BidirectionalIterator>
inline SPROUT_CXX14_CONSTEXPR bool
next_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp) {
BidirectionalIterator i = last;
if (first == last || first == --i) {
return false;
}
while (true) {
BidirectionalIterator ip1 = i;
if (comp(*--i, *ip1)) {
BidirectionalIterator j = last;
while (!comp(*i, *--j))
;
sprout::swap(*i, *j);
sprout::reverse(ip1, last);
return true;
}
if (i == first) {
sprout::reverse(first, last);
return false;
}
}
}
} // namespace detail
//
// 25.4.9 Permutation generators
//
template<typename BidirectionalIterator, typename Compare>
inline SPROUT_CXX14_CONSTEXPR bool
next_permutation(BidirectionalIterator first, BidirectionalIterator last, Compare comp) {
typedef typename std::add_lvalue_reference<Compare>::type compare_ref;
return sprout::detail::next_permutation<compare_ref>(first, last, comp);
}
template<typename BidirectionalIterator>
inline SPROUT_CXX14_CONSTEXPR bool
next_permutation(BidirectionalIterator first, BidirectionalIterator last) {
return sprout::next_permutation(
first, last,
NS_SSCRISK_CEL_OR_SPROUT::less<typename std::iterator_traits<BidirectionalIterator>::value_type>()
);
}
} // namespace sprout
#endif // #ifndef SPROUT_ALGORITHM_CXX14_NEXT_PERMUTATION_HPP