Collision Resolution Techniques in Hash Table: A Review

Abstract

One of the major challenges of hashing is achieving constant access time O(1) with an efficient memory space at a high load factor environment when various keys generate the same hash value or address. This problem causes a collision in the hash table, to resolve the collision and achieve constant access time O(1) researchers have proposed several methods of handling collision most of which introduce a non-constant access time complexity at a worst-case scenario. In this study, the worst case of several proposed hashing collision resolution techniques are analyzed based on their time complexity at a high load factor environment, it was found that almost all the existing techniques have a non-constant access time complexity. However, they all require an additional computation for rehashing keys in a hash table some of which is as a result of deadlock while iterating to insert a key. It was also found out that there are wasted slots in a hah table in all the reviewed techniques. Therefore, this work, provides an in-depth understanding of collision resolution techniques which can serve as an avenue for further research work in the field.