C++11: Map vs Vector Performance

What are the performance differences between std::map and std::vector in C++11?

In C++11, std::map is implemented as a balanced tree, providing O(log n) complexity for insertions and lookups, while std::vector offers O(1) for access but O(n) for insertions if resizing is needed.

When should I use std::map instead of std::vector?

Use std::map when you need to maintain key-value pairs with fast lookups based on keys. If you only need to store elements and access them by index, std::vector is more efficient.

Are there any scenarios where std::vector outperforms std::map?

Yes, std::vector generally outperforms std::map in scenarios where you have a large number of elements and need fast access by index, as well as when you don't require key-based lookups.

Can you give an example of when to choose one over the other?

If you're implementing a phone book where you need to search by name frequently, std::map is ideal. For a list of numbers where you only need to access them by position, std::vector is better.