C++11 Performance Comparison: Map vs Unordered Map

What are the main differences between std::map and std::unordered_map in C++11?

The main differences are that std::map is ordered and implemented as a balanced tree, while std::unordered_map is unordered and implemented as a hash table.

Which one is faster for lookups?

std::unordered_map is generally faster for lookups due to its average O(1) time complexity, compared to O(log n) for std::map.

Are there any situations where std::map is preferred?

Yes, std::map is preferred when you need to maintain order or perform range queries, as it keeps elements sorted.

What about memory usage between the two?

std::unordered_map typically uses more memory due to its hash table structure, which requires additional space for buckets.