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

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);

}

}