Some illustrative examples on the use of hash tables

Abstract

Hash tables are among the most important data structures known to mankind. Through hashing, the address of each stored object is calculated as a function of the object’s contents. Because they do not require exorbitant space and, in practice, allow for constant-time dictionary operations (insertion, lookup, deletion), hash tables are often employed in the indexation of large amounts of data. Nevertheless, there are numerous problems of somewhat different nature that can be solved in elegant fashion using hashing, with significant economy of time and space. The purpose of this paper is to reinforce the applicability of such technique in the area of Operations Research and to stimulate further reading, for which adequate references are given. To our knowledge, the proposed solutions to the problems presented herein have never appeared in the literature, and some of the problems are novel themselves.