Data Structures Questions Medium
A hash table and a hash map are both data structures that use hashing techniques to store and retrieve data efficiently. However, there is a subtle difference between the two.
A hash table is a data structure that uses an array to store key-value pairs. It uses a hash function to convert the key into an index of the array, where the corresponding value is stored. In a hash table, the keys are unique, and the values can be accessed using their corresponding keys. The main advantage of a hash table is its constant-time average case complexity for insertion, deletion, and retrieval operations.
On the other hand, a hash map is an implementation of a hash table that is typically provided as a library or built-in data structure in programming languages. It is essentially a synonym for a hash table and is used interchangeably in many contexts. The term "hash map" is often used to refer to a hash table implementation that allows null values and is not synchronized or thread-safe.
In summary, the main difference between a hash table and a hash map is that a hash table is a general term for a data structure that uses hashing, while a hash map specifically refers to a hash table implementation that may have certain characteristics or features depending on the programming language or library being used.