Abstract

Hashing or scatter table storage [3] is a very efficient data structure for the dictionary (insert, delete, member) problem. The load factor ff of a table is defined as the ratio of the number n of records or elements in the table divided by the number m of records the table can hold. The advantage of hashing schemes is that if ff ! 1, the cost of performing any of the dictionary operations can be bounded by a function of ff, the load factor, independent of the values of n and m. This compares favorably with tree-like structures and other key comparison based schemes where the cost of the dictionary operations is \Omega\Gamma/17 n). The idea of hashing is to obtain a memory address or table location where an element is stored by applying a function (hash function) to the key of the record. The candidate location provided by the hash function is not affected by the presence or absence of any other key values in the table. When two elements hash to the same tabl...

Citations