What are the differences between various data structures?

What are the differences between arrays, linked lists, and hash tables?

Arrays are fixed-size and allow fast access by index, while linked lists are dynamic and allow efficient insertions/deletions. Hash tables provide fast lookups using keys but require more memory.

Can you explain when to use a linked list over an array?

Use a linked list when you need frequent insertions and deletions, especially in large datasets, as they can be more efficient than arrays.

What about the performance differences in terms of time complexity?

Arrays have O(1) access time, linked lists have O(n) for access but O(1) for insertions/deletions, and hash tables average O(1) for lookups.

Are there any scenarios where hash tables might not be the best choice?

Yes, hash tables can have performance issues with many collisions or when memory usage is a concern, making them less ideal for small datasets.