How is the speed of operations evaluated when using HashSet in terms of time complexity?

HashSet in Java is implemented based on a hash table, so the main operations have the following time complexity:

• Adding (add): on average O(1)
• Checking for an element (contains): on average O(1)
• Removing (remove): on average O(1)

This means that operations are performed in constant time, assuming good hash distribution and no significant collisions. In the worst case (with severe collisions), the complexity can degrade to O(n), where n is the number of elements in the set.