682. Baseball Game

static int wing=[]()
{
    std::ios::sync_with_stdio(false);
    cin.tie(NULL);
    return 0;
}();

class Solution 
{
public:
    int calPoints(vector<string>& ops) 
    {
        int lastvalid=0;
        int sz=ops.size();
        vector<int> sore(sz+1,INT_MIN);
        for(string &s:ops)
        {        
            if(s[0]=='+')
            {
                sore[lastvalid]=sore[lastvalid-1]+sore[lastvalid-2];
                lastvalid++;
            }
            else if(s[0]=='D')
            {
                sore[lastvalid]=sore[lastvalid-1]*2;
                lastvalid++;
            }            
            else if(s[0]=='C')
                lastvalid--;
            else
                sore[lastvalid++]=stoi(s);
        }
        return accumulate(sore.begin(),sore.begin()+lastvalid,0);
    }
};

用栈或者vector都行，string转int可以直接stoi，学到了，妈个腿