Hashing Questions Medium
A hash table and a stack are both data structures used in computer science, but they have different characteristics and purposes.
A hash table, also known as a hash map, is a data structure that allows efficient storage and retrieval of key-value pairs. It uses a hash function to map keys to an index in an array, where the corresponding value is stored. The main advantage of a hash table is its constant-time complexity for average case operations, such as insertion, deletion, and retrieval, making it suitable for applications that require fast access to data based on a key. Hash tables are commonly used in databases, caches, and various algorithms that require efficient data lookup.
On the other hand, a stack is a linear data structure that follows the Last-In-First-Out (LIFO) principle. It is similar to a stack of plates, where the last plate placed is the first one to be removed. In a stack, elements are added and removed from the same end, known as the top. The main operations on a stack are push (adding an element to the top) and pop (removing the top element). Stacks are commonly used in programming languages for function calls, expression evaluation, and managing recursive algorithms. They are also used in various algorithms and data structures, such as depth-first search and backtracking.
In summary, the main difference between a hash table and a stack lies in their structure and usage. A hash table is used for efficient key-value storage and retrieval, while a stack is used for managing elements in a Last-In-First-Out manner.