What is the memory usage of std::unordered_map in C++11?

What is the memory usage of std::unordered_map in C++11?

The memory usage of std::unordered_map in C++11 depends on the number of elements and the load factor. Typically, it uses more memory than std::map due to its underlying hash table implementation.

How does the load factor affect memory usage?

The load factor is the ratio of the number of elements to the number of buckets. A higher load factor means less memory usage but can lead to more collisions, affecting performance.

Can you explain how collisions are handled in std::unordered_map?

Collisions in std::unordered_map are handled using chaining or open addressing. In chaining, each bucket contains a list of elements that hash to the same index.

What are the advantages of using std::unordered_map over std::map?

std::unordered_map offers average constant time complexity for lookups, insertions, and deletions, while std::map has logarithmic time complexity due to its tree structure.