javacollectionspriority-queue

Change priorityQueue to max priorityqueue

I have priority queue in Java of Integers:

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

When I call pq.poll() I get the minimum element.

Question: how to change the code to get the maximum element?

Solution

  • How about like this:

    PriorityQueue<Integer> queue = new PriorityQueue<>(10, Collections.reverseOrder());
queue.offer(1);
queue.offer(2);
queue.offer(3);
//...

Integer val = null;
while( (val = queue.poll()) != null) {
    System.out.println(val);
}

    The Collections.reverseOrder() provides a Comparator that would sort the elements in the PriorityQueue in a the oposite order to their natural order in this case.