Manual Queue Implementation

Node-Based Queue with O(1) Enqueue and Dequeue We build a classic linked-list queue. Two pointers — head and tail — let us add at the back and remove from the front in constant time. Each node holds a value and a next reference. The structure is empty when both pointers are null. Enqueue wraps the value in a new node and appends it after the tail. If the queue was empty, the new node becomes both head and tail. Dequeue captures the head's value, advances head to its…