A stack is like a stack of plates. It's "last in, first out" (LIFO), which means that the item that…
A stack stores items in a last-in, first-out (LIFO) order.
Picture a pile of dirty plates in your sink. As you add more plates, you bury the old ones further down. When you take a plate off the top to wash it, you're taking the last plate you put in. "Last in, first out."
- Fast operations. All stack operations take O(1) time.
- The call stack is a stack that tracks function calls in a program. When a function returns, which function do we "pop" back to? The last one that "pushed" a function call.
- Depth-first search uses a stack (sometimes the call stack) to keep track of which nodes to visit next.
- String parsing – stacks turn out to be useful for several types of string parsing.
You can implement a stack with either a linked list or a dynamic array – they both work pretty well:
|Stack Push||Stack Pop|
|Linked Lists||insert at head||remove at head|
|Dynamic Arrays||append||remove last element|