How to determine the time complexity of a dictionary element search operation?

The time complexity of searching for an element in a dictionary (for example, in Dictionary in Swift or HashMap in Java) is usually considered O(1) — constant, assuming good hashing and uniform distribution of keys.

This means that the search is performed in fixed time, independent of the size of the dictionary. However, in the worst case (for example, in case of hash collisions), the complexity can increase to O(n), where n is the number of elements.

Therefore, on average, searching in a dictionary is very fast and efficient.