How does a hash table store data?

• A. In a matrix format
• B. In key-value pairs using a hash function for indexing
• C. In a linked list structure
• D. In a sequential file

Answer: (B)

A hash table stores data using key-value pairs, where each key is mapped to a specific value. This mapping is facilitated by a hash function, which takes the key as input and computes an index in the underlying array where the value associated with that key will be stored. The hash function ensures a uniform distribution of keys across the array, which allows for efficient access, insertion, and deletion operations.

The strength of this approach comes from its average-case time complexity for these operations, which is typically O(1), as long as the hash function minimizes collisions—instances where two keys compute to the same index. In the event of a collision, various strategies such as chaining or open addressing may be employed to resolve the conflict and ensure that all key-value pairs are accessible.

The other methods mentioned—storing in a matrix format, linked lists, or sequential files—do not provide the same level of efficiency or simple key-based access that a hash table achieves. Thus, utilizing key-value pairs and a hash function is what fundamentally defines how data is stored in a hash table.