日常刷题2

class Solution {
public:
    int lastStoneWeight(vector<int>& stones) 
    {
        if(stones.size()<=0)
            return 0;
        if(stones.size() == 1)
            return stones[0];
        int arr[1001] = {0};
        for(int i=0;i < stones.size(); i++)
            arr[stones[i]]++;
        int j = 1000;
        int j_next;
        while(j >= 0)
        {
            arr[j] %= 2;
            if(arr[j] == 0)
            {
                j--;
                continue;
            }
            else
            {
                j_next = j-1;
                while(j_next >=0 && arr[j_next] == 0)
                    j_next--;
                if(j_next < 0)
                    break;
                else
                {
                    arr[j-j_next]++;
                    arr[j_next]--;
                    j--;
                }
            }
        }
        if(j < 0)
            return 0;
        else
            return j;
    }
};