Design a data structure that supports insert, delete, and getRandom operations, all in constant time, even when duplicate numbers are allowed. The getRandom method should return a random element from the collection with equal probability.

Design a data structure that supports insertion, deletion, and random element retrieval, all in constant time on average. You'll need to handle edge cases carefully to achieve O(1) complexity.

You're given a list of domain names with visit counts. Calculate and return the visit counts for each subdomain.