is_permutation

Interface

template<typename ForwardIterator1, typename ForwardIterator2, typename BinaryPredicate>
inline SPROUT_CONSTEXPR bool
is_permutation(ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2, BinaryPredicate pred);

template<typename ForwardIterator1, typename ForwardIterator2>
inline SPROUT_CONSTEXPR bool
is_permutation(ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2);

template<typename ForwardIterator1, typename ForwardIterator2, typename BinaryPredicate>
inline SPROUT_CONSTEXPR bool
is_permutation(ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2, ForwardIterator2 last2, BinaryPredicate pred);

template<typename ForwardIterator1, typename ForwardIterator2>
inline SPROUT_CONSTEXPR bool
is_permutation(ForwardIterator1 first1, ForwardIterator1 last1, ForwardIterator2 first2, ForwardIterator2 last2) {

Remarks

If last2 was not given in the argument list, it denotes first2 + (last1 - first1) below.

Returns

If last1 - first1 != last2 - first2, return false.

Otherwise return true if there exists a permutation of the elements in the range [first2,first2 + (last1 - first1)), beginning with ForwardIterator2 begin, such that equal(first1, last1, begin) returns true or equal(first1, last1, begin, pred) returns true; otherwise, returns false.

Examples

#include <sprout/algorithm/is_permutation.hpp>
#include <sprout/array.hpp>
#include <sprout/container.hpp>
using namespace sprout;

SPROUT_STATIC_CONSTEXPR auto input1 = array<int, 10>{{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}};
SPROUT_STATIC_CONSTEXPR auto input2 = array<int, 10>{{10, 9, 8, 1, 2, 3, 4, 5, 6, 7}};
SPROUT_STATIC_CONSTEXPR auto result = sprout::is_permutation(begin(input1), end(input1), begin(input2), end(input2));
static_assert(result, "input2 is a permutation of input1.");

Complexity

No applications of the corresponding predicate if ForwardIterator1 and ForwardIterator2 meet the requirements of random access iterators and last1 - first1 != last2 - first2.

Otherwise, exactly distance(first1, last1) applications of the corresponding predicate if equal(first1, last1, first2, last2) would return true if pred was not given in the argument list or equal(first1, last1, first2, last2, pred) would return true if pred was given in the argument list; otherwise, at worst O(N^2), where N has the value distance(first1, last1).

Recursive function invocations in O(logN) (logarithmic) depth.

Header

sprout/algorithm/is_permutation.hpp

Convenience header: sprout/algorithm.hpp