What is the PriorityQueue.remove() method in Java?

In this shot, we will learn how to use the PriorityQueue.remove() method in Java.

Introduction

The PriorityQueue.remove() method is used to remove the single instance of a particular element from the PriorityQueue.

The PriorityQueue.remove() method is present in the PriorityQueue class inside the java.util package.

Syntax

The syntax of the method is given below:

public boolean remove(E element);

Parameters

The PriorityQueue.remove() method accepts one parameter:

  • Element: The element whose instance is to be removed from the PriorityQueue.

Return value

The PriorityQueue.remove() method returns a boolean value:

  • True: The specified element is present in the PriorityQueue.
  • False: The specified element is not present in the PriorityQueue.

Code

Let’s look at the code below.

import java.util.*;
class Main 
{
  public static void main(String[] args)
  {
    PriorityQueue<Integer> pq = new PriorityQueue<Integer>();
    pq.add(2);
    pq.add(28);
    pq.add(6);
    pq.add(80);
    pq.add(28);
    pq.add(7);
    pq.add(15);
    System.out.println("Original priority queue is: " + pq);
    
    boolean element_removed = pq.remove(28);
    if (element_removed)
      System.out.println("Element removed.");
    else
      System.out.println("Element is not removed.");
    
    element_removed = pq.remove(78);
    if (element_removed)
      System.out.println("Element removed.");
    else
      System.out.println("Element is not removed.");
    
    System.out.println("The priority queue after removing the element = 28 is: " + pq);
  }
}

Explanation

  • Line 1: We import the required package.

  • Line 2: We create the Main class.

  • Line 4: We define the main() method.

  • Line 6: We declare a PriorityQueue that consists of Integer type elements.

  • Lines 8 to 14: We use the PriorityQueue.add() method to insert the elements in the PriorityQueue.

  • Line 16: We print the elements present in the priority queue.

  • Line 18: We call the remove() method and pass the element that needs to be removed.

  • Lines 20 to 23: We check whether the element was removed or not and print the message accordingly.

  • Line 25: We call the remove() method again and pass a different element that needs to be removed.

  • Lines 27 to 30: We check whether the element was removed or not and print the message accordingly.

  • Line 32: We print the elements present after applying the remove() method on the priority queue.

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