How do I use unordered_map in C++?

What is an unordered_map in C++?

An unordered_map is a part of the C++ Standard Library that stores key-value pairs in no particular order, allowing for fast retrieval.

How do I insert elements into an unordered_map?

You can insert elements using the insert method or the subscript operator. For example: myMap[key] = value;.

Can I use custom types as keys?

Yes, you can use custom types as keys, but you need to provide a hash function and an equality function for them.

What are the advantages of using unordered_map over map?

The main advantage is that unordered_map offers average constant time complexity for lookups, insertions, and deletions, while map has logarithmic time complexity.