Profit Maximisation InterviewBit Heap.java

public class Solution {
    public int solve(ArrayList<Integer> A, int B) {
        // PriorityQueue for max heap
        // By default priority queue is min heap
        // we want to maximize profit that is reason we are using max heap
        PriorityQueue<Integer> pq = new PriorityQueue<>(Collections.reverseOrder());
        // add all the elements into the heap
        for(int x: A) pq.add(x);
        int ans = 0;
        
        // select b elements out of heap
        while(B-- > 0) {
            int val = pq.poll();
            ans += val;
            // add remaining people to priority queue
            pq.add(val - 1);
        }
        
        return ans;
    }
}