What is the time complexity of adding an element to a dictionary?

In dictionaries (for example, Dictionary in Swift), the operation of adding an element typically has an amortized time complexity of O(1). This is achieved by using hash tables, where hash computation and insertion are performed in constant time on average. However, in the worst case, such as in collisions or when resizing the internal array is necessary, the complexity can temporarily increase to O(n), where n is the number of elements in the dictionary.