A queue is a fundamental data structure that follows the First-In-First-Out (FIFO) principle. In a queue, the first element added to the queue is the first one to be removed. This ordering ensures that the oldest element in the queue is processed or removed before newer elements.
Key characteristics of a queue:
-
Enqueue (Insertion): Adding an element to the back (end) of the queue is known as "enqueue" operation.
-
Dequeue (Deletion): Removing the element from the front (head) of the queue is known as "dequeue" operation.
-
Front: The front of the queue is the position where dequeue operations occur.
-
Rear (or Back): The rear (or back) of the queue is the position where enqueue operations occur.
Queues are widely used in various computer science applications, including process scheduling, task management, breadth-first search algorithms, and handling requests in networking systems.
There are different types of queues, including:
-
Linear Queue: Elements are arranged in a linear structure. Enqueue and dequeue operations occur at opposite ends.
-
Circular Queue: Similar to a linear queue, but the last element is connected to the first element, forming a circular structure.
-
Priority Queue: Elements have associated priorities, and the element with the highest priority is dequeued first.
-
Double-Ended Queue (Deque): Allows enqueue and dequeue operations at both ends of the queue.
Queues can be implemented using various data structures, such as arrays or linked lists, depending on the specific requirements and constraints of the application.
