1046. Last Stone Weight

time: nlog(n)

space: O(n)

class Solution {
    public int lastStoneWeight(int[] stones) {
        PriorityQueue<Integer> pq = new PriorityQueue<>(Collections.reverseOrder());
        for (int s : stones) {
            pq.offer(s);
        }
        while (pq.size() > 1) {
            pq.offer(pq.poll() - pq.poll());
        }
        return pq.poll();
    }
}