An adaptive constant time hashing scheme for dynamic key set

Hashing is an important tool in randomized algorithms, with applications in such diverse fields including information retrieval, data mining, cryptology and parallel algorithms. However, the worst case behavior of a regular hash-based searching is O(n). Perfect hashing is a solution to this problem that offers a worst case performance of O(1) only for the static key set. In this paper we have proposed an adaptive hashing scheme that works on dynamic key sets and still enables keys to be searched in constant time. It has been further established that, if the hash functions are carefully chosen, then the space requirement of the hash structure is O(n).