Circular Queue
Explore how circular queues in JavaScript optimize memory by reusing freed positions through pointer wrapping with the modulo operator. Understand their structure, key operations like enqueue and dequeue, and why they are essential for fixed-size queue implementations in systems requiring efficient, constant-time operations.
Before introducing circular queues, it is important to understand the problem they address.
In a simple array-based queue, elements are added at the rear and removed from the front. As dequeue operations occur, the front index advances. Over time, the positions at the beginning of the array become empty and are never used again. Eventually, the rear reaches the end of the array, and the queue appears full; even though much of the array is actually empty.
This is a serious waste of memory. Consider a queue of size 5 that has had two dequeue operations:
The rear is at the last index. If we try to enqueue a new element, the queue reports overflow, even though positions 0 and 1 are free. A circular queue solves this directly.
What is a circular queue?
A circular queue is a queue in which the last position of the array is connected back to the first position, forming a logical circle. When ...