Changing Java PriorityQueue to a Max PQ [duplicate]

Question

The Priority Queue implementation in the Java standard library appears to be a min Priority Queue which I found somewhat confusing. In order to turn it into a max one I created a custom comparator object.

Comparator<Integer> cmp = new Comparator<Integer>() {     public int compare( Integer x, Integer y )     {         return y - x;     } }; 

I was wondering if there was a more elegant solution. Essentially I wan't a generic priority queue that could be used to implement Dijkstras etc. I didn't even realise there would be ones which operated in reverse :/

Answer 1

Here is a code snippet using Collections.reverseOrder()-

    PriorityQueue<Integer> maxPQ = new PriorityQueue<Integer>(20,Collections.reverseOrder()); 

You also need to provide the initial capacity of the Priority Queue (20 here) along with the Comparator.

Answer 2

Use Java's Collections.reverseOrder() comparator.

Java Reference