What characteristic makes a good hash function?

A good hash function is characterized by its ability to randomly distribute items across the hash table. This means that when a set of inputs is processed, the resulting hash values should be uniformly spread out to avoid clustering, which can lead to inefficient performance. If a hash function produces significant clustering, it can result in many collisions—where different inputs generate the same hash value—which can degrade the efficiency of hash table operations.

Uniform distribution minimizes the likelihood of collisions and ensures that the operations such as insertion, deletion, and searching can be performed in constant time on average. A well-distributed hash function allows for optimal space utilization within the hash table and promotes more efficient data retrieval and management.

While fast execution, simplicity, and producing unique outputs can also be desirable traits in a hash function, they do not capture the critical aspect of effective hash table performance as well as the characteristic of random distribution does. It’s the balance of distribution that plays a pivotal role in the overall efficiency of hash operations.