What is the time complexity of searching for an element in an unordered_set container?

In an unordered_set container, searching for an element on average has a time complexity of O(1), meaning constant time. This is achieved through the use of a hash table.

However, in the worst case, with a large number of collisions, the complexity can degrade to O(n), where n is the number of elements in the container. But in practice, such cases are rare with a proper hash function implementation and a sufficiently large table size.