Question

g Select an appropriate expression to complete the following method, which is designed to return the sum of the two smallest values in the parameter array numbers. public static int sumTwoLowestElements(int[] numbers) { PriorityQueue values = new PriorityQueue<>(); for (int num: numbers) { values.add(num); } ______________________ }

Answer 1

Answer:

import java.util.Comparator;

import java.util.PriorityQueue;

 

public class PriorityQueueTest {

 

static class PQsort implements Comparator<Integer> {

 

 public int compare(Integer one, Integer two) {

  return two - one;

 }

}

 

public static void main(String[] args) {

 int[] ia = { 1, 10, 5, 3, 4, 7, 6, 9, 8 };

 PriorityQueue<Integer> pq1 = new PriorityQueue<Integer>();

 

 // use offer() method to add elements to the PriorityQueue pq1

 for (int x : ia) {

  pq1.offer(x);

 }

 

 System.out.println("pq1: " + pq1);

 

 PQsort pqs = new PQsort();

 PriorityQueue<Integer> pq2 = new PriorityQueue<Integer>(10, pqs);

 // In this particular case, we can simply use Collections.reverseOrder()

 // instead of self-defined comparator

 for (int x : ia) {

  pq2.offer(x);

 }

 

 System.out.println("pq2: " + pq2);

 

 // print size

 System.out.println("size: " + pq2.size());

 // return highest priority element in the queue without removing it

 System.out.println("peek: " + pq2.peek());

 // print size

 System.out.println("size: " + pq2.size());

 // return highest priority element and removes it from the queue

 System.out.println("poll: " + pq2.poll());

 // print size

 System.out.println("size: " + pq2.size());

 

 System.out.print("pq2: " + pq2);

 

}

}