How does collision handling work in C++11's std::unordered_map?

How does collision handling work in C++11's std::unordered_map?

In C++11, std::unordered_map uses a hash table for storage. When two keys hash to the same index, a collision occurs.

What methods does it use to resolve these collisions?

It typically uses separate chaining, where each bucket contains a linked list of entries that hash to the same index.

Are there any performance implications with this method?

Yes, if many collisions occur, it can degrade performance to O(n) for lookups, but with a good hash function, it remains efficient.

How can I improve the performance of my unordered_map?

You can improve performance by choosing a good hash function and ensuring a low load factor by reserving space in advance.