Which data structure is best suited for storing a collection of elements with unique keys?

The best choice for storing a collection of elements with unique keys is a hash table. Hash tables are designed to efficiently handle key-value pairs, where each key is unique. They utilize a hash function to compute an index in an array where the corresponding value can be stored. This allows for rapid insertion, deletion, and retrieval operations, typically performed in constant time, O(1), under ideal conditions.

In addition, hash tables automatically manage uniqueness; if a new entry is added with a key that already exists, it can either be updated or rejected based on the implementation. This feature is particularly beneficial for applications requiring quick access to data tied to unique identifiers or keys.

Other data structures like arrays and linked lists do not inherently enforce key uniqueness and may require additional steps to check for duplicates. Stacks, on the other hand, operate on a Last In First Out (LIFO) principle and are not designed for key-based access, making them unsuitable for this purpose. Thus, the efficiency in handling collections with unique keys firmly establishes the hash table as the optimal choice.