Day37_LeetCode1046.java

class Solution {
    public int lastStoneWeight(int[] stones) {
        PriorityQueue<Integer> pq = new PriorityQueue<>(Collections.reverseOrder());
        for (int stone : stones) {
            pq.add(stone);
        }
        
        while (pq.size() > 1) {
            int y = pq.poll();
            int x = pq.poll();
            if (x != y) {
                pq.add(y - x);
            }
        }
        
        if (pq.isEmpty()) {
            return 0;
        } else {
            return pq.peek();
        }
    }
}