# What Are the Various Types of Queues in Data Structure?

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Larry Thompson

Queues are a fundamental concept in data structures. They are widely used in computer science and programming for various applications. In this article, we will explore the different types of queues and their characteristics.

## What is a Queue?

A queue is an ordered collection of elements that follows the First-In-First-Out (FIFO) principle. It operates like a real-life queue, where the first person entering the line is the first one to be served. Similarly, in a queue, the element that is inserted first is the first one to be removed.

## Types of Queues

### 1. Simple Queue

The simple queue is the most basic type of queue.

It only allows elements to be inserted at one end (rear) and removed from the other end (front). This type of queue follows the FIFO principle.

### 2. Circular Queue

A circular queue overcomes one limitation of a simple queue – once the rear reaches the end, we cannot insert any more elements even if there are empty spaces in front. In a circular queue, when we reach the end, we wrap around to the beginning and continue inserting elements if there is space available.

### 3. Priority Queue

Unlike other types of queues, a priority queue assigns a priority value to each element.

The element with higher priority gets dequeued before elements with lower priority. If two elements have the same priority, they follow FIFO order.

### 4. Deque (Double Ended Queue)

A deque is a versatile type of queue that allows insertion and removal of elements from both ends (front and rear). It can function as both a stack and a queue simultaneously.

### 5. Priority Deque

Similar to a priority queue, a priority deque assigns a priority value to each element. It allows insertion and removal of elements from both ends based on their priority values.

## Conclusion

Understanding the different types of queues is essential for designing efficient algorithms and solving various problems. Each type has its own advantages and use cases.

By choosing the right type of queue, you can optimize your code and improve its performance.