Change priorityQueue to max priorityqueue

Question

I have priority queue in Java of Integers:

 PriorityQueue pq= new PriorityQueue();

When I call pq.poll(

Answer 1

The elements of the priority queue are ordered according to their natural ordering, or by a Comparator provided at queue construction time.

The Comparator should override the compare method.

int compare(T o1, T o2)

Default compare method returns a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second.

The Default PriorityQueue provided by Java is Min-Heap, If you want a max heap following is the code

public class Sample {
    public static void main(String[] args) {
        PriorityQueue q = new PriorityQueue(new Comparator() {

            public int compare(Integer lhs, Integer rhs) {
                if(lhsrhs) return -1;
                return 0;
            }
        });
        q.add(13);
        q.add(4);q.add(14);q.add(-4);q.add(1);
        while (!q.isEmpty()) {
            System.out.println(q.poll());
        }
    }

}

Reference :https://docs.oracle.com/javase/7/docs/api/java/util/PriorityQueue.html#comparator()