Maxheap vs priorityqueue confusion

Question

Suppose we want to sort a hashmap based on the value. We implement a priorityQueue with comparator to do this. As a result, the resulting pq is sorting from the largest to the smallest from index 0 to end.

Here is the code:

PriorityQueue<Map.Entry<Integer, Integer>> pq = new PriorityQueue<Map.Entry<Integer, Integer>>(
                new Comparator<Map.Entry<Integer, Integer>>() {
                    @Override
                    public int compare(Entry<Integer, Integer> o1, Entry<Integer, Integer> o2) {
                        return o2.getValue() - o1.getValue();
                    }
                });

However, somebody said that it is a maxheap, I understand that heap is just parent value greater than child value but I cannot understand why it is a maxheap? It is just implementing the comparator in a priorityQueue? How does this relates to heap?

score 2 · Accepted Answer · answered Jul 21 '16 at 04:18

2

Internal structure of a priority queue in java is heap.
This comparator will be used to compare with the parent value in priority queue.

answered Jul 21 '16 at 04:18

MMHossain

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Maxheap vs priorityqueue confusion

1 Answers1