NavigableSet in Java
NavigableSet interface provides some interesting methods. Their method signatures are as follows: Method | Description ------ | ------ E lower(E e) | Returns greatest element that is < e, or null if no such element E floor(E e) | Returns greatest element that is <= e, or null if no such element E ceiling(E e) | Returns smallest element that is >= e, or null if no such element E higher(E e) | Returns smallest element that is > e, or null if no such element