When should I use map or vector in C++?

When should I use map or vector in C++?

You should use a vector when you need a dynamic array that allows fast access by index. Use a map when you need to associate keys with values and require fast lookups.

Can you explain the performance differences between them?

Sure! Vectors provide O(1) access time for elements, while maps have O(log n) access time due to their underlying tree structure. However, maps allow for key-value associations.

What about memory usage?

Vectors generally use less memory than maps because they store elements in a contiguous block. Maps, on the other hand, require additional memory for storing keys and pointers.

Are there any scenarios where one is clearly better than the other?

Yes! If you need to maintain order and access elements by index, use a vector. If you need to quickly search for values based on unique keys, a map is the better choice.