What are some use cases for std::unordered_map in C++11?

What are some practical use cases for std::unordered_map in C++11?

std::unordered_map is great for scenarios where you need fast lookups, like caching results or counting occurrences.

Can you give me an example of using it for counting occurrences?

Sure! You can use it to count word frequencies in a text by iterating through each word and incrementing its count in the map.

What about using it for caching? How would that work?

For caching, you can store computed results in an unordered_map, using the input as the key and the result as the value.

Are there any performance considerations I should be aware of?

Yes, while unordered_map offers average constant time complexity for lookups, it can degrade to linear time in worst-case scenarios due to hash collisions.