C++ STL: Deque vs Vector

What are the main differences between deque and vector in C++ STL?

The main differences are in their memory allocation and performance. Vectors are contiguous in memory, while deques are not.

When should I use deque instead of vector?

Use deque when you need efficient insertions and deletions at both ends, as it provides O(1) time complexity for these operations.

Are there any performance trade-offs I should be aware of?

Yes, vectors have better cache locality and are generally faster for random access, while deques may have overhead due to their non-contiguous memory.

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

Sure! If you're implementing a queue where you frequently add and remove elements from both ends, use deque. For a simple dynamic array, use vector.