Permutations

std::prev_permutation and std::next_permutation return the previous smaller or next bigger permutation of the newly ordered range. If a smaller or bigger permutation is not available, the algorithms return false. Both algorithms need bidirectional iterators. Per default, the predefined sorting criterion std::less is used. If we use our sorting criterion, it has to obey the strict weak ordering. If not, the program will be undefined.

std::prev_permutation: Applies the previous permutation to the range.