DSA: Hash Table - Expanded Questions

A hash table is a data structure that maps keys to values using a hashing function. It is useful for fast lookup, insertion, and deletion operations. Hash functions are essential in hash tables as they determine where to store and retrieve data. Common uses of hash tables include caching, indexing, and dictionary implementations. Implementing a hash table involves defining methods like insert, get, delete, and resize, as well as handling collisions. Separate chaining and open addressing are two main techniques for handling collisions, with separate chaining using linked lists and open addressing using probing. The time complexity of hash table operations depends on the load factor and collision resolution strategy. A load factor that is too high can lead to poor performance, so resizing is necessary. Hash tables can be optimized by using better hash functions, resizing, or different collision resolution strategies. They can also be used in real-world applications such as LRU caches, spell checkers, and solving the Two Sum problem. However, hash tables have limitations, including high memory consumption and difficulties in implementing custom hash functions.