What are the performance differences between TreeSet and HashSet?

What are the performance differences between TreeSet and HashSet?

TreeSet is implemented as a Red-Black tree, which means it maintains order and has O(log n) time complexity for add, remove, and contains operations. HashSet, on the other hand, uses a hash table, providing average O(1) time complexity for these operations, but it does not maintain any order.

When should I use TreeSet over HashSet?

You should use TreeSet when you need to maintain a sorted order of elements or require range queries. If you only need fast access and don't care about order, HashSet is the better choice.

Are there any memory usage differences between them?

Yes, TreeSet generally uses more memory than HashSet due to the overhead of maintaining the tree structure. HashSet is more memory-efficient for storing elements without order.

Can you give an example of when to use each?

Sure! Use TreeSet for applications like a leaderboard where you need sorted scores. Use HashSet for a collection of unique user IDs where order doesn't matter.