How does C++ handle hash collisions in the standard library?

How does C++ handle hash collisions in the standard library?

In C++, hash collisions are managed by the standard library's unordered containers, like unordered_map and unordered_set. When two keys hash to the same value, the library uses a technique called chaining or open addressing to resolve the collision.

Can you explain how chaining works?

Sure! In chaining, each bucket in the hash table contains a list (or another data structure) of all entries that hash to the same index. When a collision occurs, the new entry is simply added to the list in that bucket.

What about open addressing? How is it different?

Open addressing resolves collisions by finding another open slot within the hash table itself. When a collision occurs, it probes the table using a specific sequence until an empty slot is found.

Which method is generally preferred in practice?

It depends on the use case. Chaining is often simpler to implement and can handle a larger number of collisions, while open addressing can be more space-efficient but may require careful management of load factors.