Queue • Core Implementation

Queue using Linked List

Implementing a Queue with a Linked List solves the "False Overflow" and fixed-size limitations of Array Queues. It grows dynamically as needed.

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Two Pointers

You maintain `front` pointing to the head of the list, and `rear` pointing to the tail. Both start as `NULL`.

Enqueue (Push)

Always add to the `rear` (tail). `rear.next = new Node`, then `rear = new Node`. If the queue is empty, both pointers point to the new node.

Dequeue (Pop)

Always remove from the `front` (head). Save the value, then `front = front.next`. If `front` becomes `NULL` after popping, remember to set `rear = NULL` too!

Queue is Empty

Code Tracker

:::

1function push(val) {

2 let newNode = new Node(val);

3 if (front === null) {

4 front = rear = newNode;

5 return;

6 }

7 rear.next = newNode;

8 rear = newNode;

9}

10function pop() {

11 if (front === null) return 'Underflow';

12 let val = front.val;

13 front = front.next;

14 if (front === null) rear = null;

15 return val;

16}

Queue Linked List

Queue Linked List

Queue using Linked List

Two Pointers

Enqueue (Push)

Dequeue (Pop)

Queue using Linked List

Two Pointers

Enqueue (Push)

Dequeue (Pop)