Sprout/sprout/algorithm/is_permutation.hpp
2012-10-06 13:53:07 +09:00

66 lines
2.4 KiB
C++

#ifndef SPROUT_ALGORITHM_IS_PERMUTATION_HPP
#define SPROUT_ALGORITHM_IS_PERMUTATION_HPP
#include <sprout/config.hpp>
#include <sprout/iterator/operation.hpp>
#include <sprout/algorithm/count.hpp>
#include <sprout/algorithm/count_if.hpp>
#include HDR_ITERATOR_SSCRISK_CEL_OR_SPROUT
#include HDR_FUNCTIONAL_SSCRISK_CEL_OR_SPROUT
namespace sprout {
// Copyright (C) 2011 RiSK (sscrisk)
namespace detail {
template<typename ForwardIterator1, typename ForwardIterator2>
inline SPROUT_CONSTEXPR bool
is_permutation_impl(
ForwardIterator1 first1, ForwardIterator1 last1,
ForwardIterator2 first2, ForwardIterator1 first1_
)
{
return first1_ == last1 ? true
: sprout::count(first1, last1, *first1_)
== sprout::count(first2, sprout::next(first2, NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1)), *first1_)
&& sprout::detail::is_permutation_impl(first1, last1, first2, sprout::next(first1_))
? true
: false
;
}
template<typename ForwardIterator1, typename ForwardIterator2, typename BinaryPredicate>
inline SPROUT_CONSTEXPR bool
is_permutation_impl(
ForwardIterator1 first1, ForwardIterator1 last1,
ForwardIterator2 first2, ForwardIterator1 first1_,
BinaryPredicate pred
)
{
return first1_ == last1 ? true
: sprout::count_if(first1, last1, NS_SSCRISK_CEL_OR_SPROUT::bind2nd(pred, *first1_))
== sprout::count_if(
first2, sprout::next(first2, NS_SSCRISK_CEL_OR_SPROUT::distance(first1, last1)),
NS_SSCRISK_CEL_OR_SPROUT::bind2nd(pred, *first1_)
)
&& sprout::detail::is_permutation_impl(first1, last1, first2, sprout::next(first1_), pred)
? true
: false
;
}
} // namespace detail
// 25.2.12 Is permutation
template<typename ForwardIterator1, typename ForwardIterator2>
inline SPROUT_CONSTEXPR bool
is_permutation(ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2) {
return sprout::detail::is_permutation_impl(first1, last1, first2, first1);
}
template<typename ForwardIterator1, typename ForwardIterator2, typename BinaryPredicate>
inline SPROUT_CONSTEXPR bool
is_permutation(ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2, BinaryPredicate pred) {
return sprout::detail::is_permutation_impl(first1, last1, first2, first1, pred);
}
} // namespace sprout
#endif // #ifndef SPROUT_ALGORITHM_IS_PERMUTATION_HPP