Java: Retrieve and remove the first element

Last update on March 12 2025 13:34:17 (UTC/GMT +8 hours)

Write a Java program to retrieve and remove the first element.

Sample Solution:-

Java Code:

import java.util.PriorityQueue;

  public class Exercise9 {
  public static void main(String[] args) {
   // Create Priority Queue
      PriorityQueue<Integer> pq1 = new PriorityQueue<Integer>();  
      PriorityQueue<Integer> pq2 = new PriorityQueue<Integer>();     
   // Add numbers in the Priority Queue
   pq1.add(10);
   pq1.add(22);
   pq1.add(36);
   pq1.add(25);
   pq1.add(16);
   pq1.add(70);
   pq1.add(82);
   pq1.add(89);
   pq1.add(14);
   System.out.println("Original Priority Queue: "+pq1);
   System.out.println("Removes the first element: "+pq1.poll());
   System.out.println("Priority Queue after removing first element: "+pq1);
   }    
}

Sample Output:

Original Priority Queue: [10, 14, 36, 16, 22, 70, 82, 89, 25]          
Removes the first element: 10                                          
Priority Queue after removing first element: [14, 16, 36, 25, 22, 70, 8
2, 89] 

For more Practice: Solve these Related Problems:

• Write a Java program to remove the first element of a PriorityQueue using poll() and then print the remaining elements.
• Write a Java program to compare the element returned by peek() with the one removed by poll() in a PriorityQueue.
• Write a Java program to repeatedly remove the head element from a PriorityQueue until it is empty, printing each element.
• Write a Java program to implement a method that removes the first element from a PriorityQueue and returns it, then validate the removal.

Java Code Editor:

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