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Sprout/sprout/algorithm/is_permutation.hpp
2012-04-01 22:15:09 +09:00

74 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>
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, 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>
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, 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>
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>
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