Design a data structure that supports insert, delete, search, and retrieve in constant time.

A hash map (or hash table) is a suitable data structure for achieving constant time complexity (O(1)) for insert, delete, search, and retrieve operations. It works by using a hash function to map keys to indices in an array, allowing for direct access to the corresponding values. While the average time complexity is O(1), worst-case scenarios (due to hash collisions) can degrade performance to O(n), though this is often mitigated through techniques like separate chaining or open addressing.