Queues

In the world of data structures, a queue is another linear data structure that follows the First In, First Out (FIFO) principle. It is similar to a queue of people waiting in line for a ticket, where the person who arrived first gets the ticket first.

Applications of Queues

Queues have various applications in computer science and are commonly used in algorithms and simulations. Some examples include:

1. Job Scheduling: In operating systems, queues are used to manage processes waiting to be executed by the CPU. The process that arrives first is given priority.

2. Breadth-First Search: Queues are used to implement breadth-first search (BFS) algorithm in graph traversal. BFS visits all the vertices of a graph in breadth-first order.

3. Buffer: Queues are used as buffers in data communication systems to temporarily store data before it is processed.

Java Example

Let's take a look at an example of creating and manipulating a queue using Java:

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import java.util.LinkedList;

import java.util.Queue;

​

public class Main {

  public static void main(String[] args) {

    // Create a queue

    Queue<String> queue = new LinkedList<>();

​

    // Adding elements to the queue

    queue.add("Alice");

    queue.add("Bob");

    queue.add("Charlie");

    queue.add("David");

​

    // Accessing the front element of the queue

    String frontElement = queue.peek();

    System.out.println("Front element: " + frontElement);

​

    // Removing elements from the queue

    String removedElement = queue.remove();

    System.out.println("Removed element: " + removedElement);

​

    // Checking if the queue is empty

    boolean isEmpty = queue.isEmpty();

    System.out.println("Is the queue empty? " + isEmpty);

  }

}