cpp/container/unordered multiset

is an associative container that contains set of possibly non-unique objects of type Key. Search, insertion, and removal have average constant-time complexity.

Internally, the elements are not sorted in any particular order, but organized into buckets. Which bucket an element is placed into depends entirely on the hash of its value. This allows fast access to individual elements, since once hash is computed, it refers to the exact bucket the element is placed into.

The iteration order of this container is not required to be stable (so, for example, std cannot be used to compare two s), except that every group of elements whose keys compare equivalent (compare equal with key_eq as the comparator) forms a contiguous subrange in the iteration order, also accessible with std.

meets the requirements of, ,.