C++: Unordered Map vs Map

What are the main differences between unordered_map and map in C++?

The main differences are that unordered_map uses hash tables for storage, providing average O(1) time complexity for lookups, while map uses a balanced tree structure, offering O(log n) time complexity.

When should I use unordered_map instead of map?

You should use unordered_map when you need faster access times and don't require the elements to be sorted. It's ideal for scenarios where order doesn't matter.

Are there any drawbacks to using unordered_map?

Yes, unordered_map can have higher memory usage due to its hash table implementation, and it doesn't maintain the order of elements.

Can you give an example of when to use each?

Sure! Use map when you need to maintain sorted order, like in a priority queue. Use unordered_map for fast lookups, like caching results.