Deletion from open-address hash table is not so easy as deletion from chained
hash table, because in open-address table we can't simply mark a slot
containing deleted key as empty. Search for keys may become incorrect. The
classical method to implement deletion is to mark slots in hash table by three
values: "free", "busy", "deleted". That method is easy to implement, but there
are some disadvantages. In this article we consider alternative method of
deletion keys, where we avoid using the mark "deleted". The article contains
the implementation of the method in Java.