leetcode 1046. Last Stone Weight
思路：用优先队列简单模拟，挑最大的两块撞一下。
代码：
class Solution {
public:int lastStoneWeight(vector<int>& stones) {priority_queue<int> q;for (auto a:stones)q.push(a);while (!q.empty()){if (q.size() == 1)return q.top();else{auto max1 = q.top();q.pop();auto max2 = q.top();q.pop();auto left = abs(max2 - max1);if (left != 0)q.push(left);}}return 0;}
};