hash table vs array

A hash table and an array are two data structures used in computer science. A hash table, also known as a hash map, is a data structure that allows efficient insertion, deletion, and retrieval operations. It uses a hash function to map keys to an array, known as a hash table, where the corresponding values are stored. Hash tables provide fast access to data, with an average time complexity of O(1) for most operations. On the other hand, an array is a contiguous block of memory where elements are stored sequentially, accessible through their indices. Arrays offer constant-time random access to elements, but their size is fixed, and resizing can be costly. In terms of comparison, a key distinguishing factor is how data is accessed. In an array, elements can be accessed directly using indices, making it efficient for random access. In contrast, a hash table provides efficient access based on keys, making it suitable for tasks like searching and indexing. Additionally, arrays have a fixed size and require memory allocation before usage, while hash tables can dynamically grow or shrink based on the number of elements stored. In summary, a hash table and an array differ in how data is accessed and their flexibility in size. Hash tables offer efficient access based on keys and dynamic resizing, while arrays provide constant-time random access but have a fixed size.

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