An array is a collection of elements stored in a contiguous block of memory, which allows direct access to any element using its index in O(1) time. Arrays have a fixed size in static languages, but dynamic arrays (like C++’s vector) can grow or shrink as needed. They are efficient for random access and have better cache locality, making sequential operations faster. However, inserting or deleting elements in the middle or at the beginning of an array requires shifting elements, which takes O(n) time, making such operations slower.

On the other hand, a linked list consists of nodes scattered in memory, where each node stores the data and a pointer to the next node (or previous node in doubly linked lists). Linked lists allow efficient insertion and deletion at the beginning or middle in O(1) time, provided we have a pointer to the relevant node. However, they have slower access times since you need to traverse nodes sequentially (O(n) time) to reach a specific element. Linked lists also use extra memory for storing pointers and have poorer cache performance due to scattered memory allocation.