```
template<class BidirectionalIterator>
bool next_permutation(BidirectionalIterator first,
BidirectionalIterator last);
template<class BidirectionalIterator, class Compare>
bool next_permutation(BidirectionalIterator first,
BidirectionalIterator last, Compare comp);
```

Requires:
BidirectionalIterator shall satisfy the
ValueSwappable requirements ([swappable.requirements]).

```
template<class BidirectionalIterator>
bool prev_permutation(BidirectionalIterator first,
BidirectionalIterator last);
template<class BidirectionalIterator, class Compare>
bool prev_permutation(BidirectionalIterator first,
BidirectionalIterator last, Compare comp);
```

Requires:
BidirectionalIterator shall satisfy the
ValueSwappable requirements ([swappable.requirements]).