Saved from https://leetcode.com/problems/last-stone-weight/submissions/

lc1046

class Solution {
    // Time: O(nlogn)
    // Space: O(n)
    public int lastStoneWeight(int[] stones) {
        if (stones.length == 1) {
            return stones[0];
        }
        PriorityQueue<Integer> queue = new PriorityQueue<>(Collections.reverseOrder());
        for (int weight : stones) {
            queue.add(weight);
        }
        while (queue.size() > 1) {
            int y = queue.poll();
            int x = queue.poll();
            queue.add(y-x);
        }
        return queue.poll();
    }
}