A stack is a linear data structure that operates on a Last In, First Out (LIFO) basis. This means that the last element added to the stack is the first to be removed. Access to elements in a stack is sequential, making it different from arrays where random access is possible. Key operations in a stack include:
- Push(x): Adds an element ‘x’ to the top of the stack.
- Pop(): Removes and returns the top element of the stack.
- Peek() or Top(): Returns the top element without removing it.
- isEmpty(): Determines if the stack is empty.
- isFull(): Checks if the stack has reached its capacity.
Stacks can be implemented using arrays (static) or linked lists (dynamic), with the “top” pointer indicating the last inserted element.
What is a Queue? A queue is also a linear data structure but operates on a First In, First Out (FIFO) basis. This structure means that the first element added to the queue is the first to be removed. Operations in a queue are performed at two ends:
- Enqueue(): Adds an element to the rear of the queue.
- Dequeue(): Removes and returns the element at the front of the queue.
Like stacks, queues use pointers; however, they utilize two: a “front” pointer for the first element, and a “rear” pointer for the last element added.
Similarities Between Stack and Queue: Both stacks and queues are linear structures that allow elements to be stored and accessed sequentially. They are also dynamic, capable of resizing based on the needs of the operation.
Differences Between Stack and Queue:
| Feature | Stack | Queue |
|---|---|---|
| Order of Operation | LIFO (Last In First Out) | FIFO (First In First Out) |
| Ends for Operations | Single end (top) for both insertion and deletion | Two ends: front for deletion, rear for insertion |
| Pointer Usage | One pointer (top) | Two pointers (front and rear) |
| Core Operations | Push and Pop | Enqueue and Dequeue |
| Empty Condition Check | top == -1 indicates empty | front == -1 or front > rear indicates empty |
| Full Condition Check | top == max - 1 indicates full | rear == max - 1 indicates full |
| Variants | Generally no variants | Includes priority queues, circular queues, and double-ended queues (deque) |
| Implementation Complexity | Simpler | More complex |
| Visualization | Typically vertical | Typically horizontal |
Read More …
Coding Basics: Understanding How Linked Lists Work – A Beginner’s Guide – https://kamleshsingad.com/coding-basics-understanding-how-linked-lists-work-a-beginners-guide/
Distinguishing Searching from Sorting: Understanding Algorithmic Approaches – https://kamleshsingad.com/distinguishing-searching-from-sorting-understanding-algorithmic-approaches/
Matrix Data Structure – https://kamleshsingad.com/matrix-data-structure/
