class Solution {
public:
int lastStoneWeight(vector<int>& stones) {
int x,y;
while(1)
{
if(stones.size() <=1)
{
break;
}
sort(stones.begin(),stones.end());
x = stones[stones.size()-1];
y = stones[stones.size()-2];
stones.erase(stones.begin()+ (int)stones.size()-2,stones.end());
if(x!=y)
{
stones.push_back(x-y);
}
}
return stones.size() == 0 ? 0 : stones[0];
}
};
