Unordered Associative
Containers
Collaboration diagram for Unordered Associative:

Unordered associative containers allow fast retrieval of data based on keys.

Each container type is parameterized on a `Key` type, a `Hash` type providing a hashing functor, and an ordering relation used to sort the elements of the container.

All unordered associative containers must meet certain requirements, summarized in tables.