How does using unordered_map in C++11 affect performance?

What are the performance benefits of using unordered_map in C++11?

Using unordered_map in C++11 provides average constant time complexity for insertions, deletions, and lookups.

Are there any downsides to using unordered_map compared to map?

Yes, unordered_map uses more memory due to its hash table implementation and may have worse performance in worst-case scenarios.

How does the hash function impact the performance of unordered_map?

The hash function determines how keys are distributed in the table; a good hash function minimizes collisions, improving performance.

Can you give an example of when to use unordered_map over map?

Use unordered_map when you need fast access and don't require ordered keys, like in caching or frequency counting.