//url:https://leetcode.com/problems/baseball-game/description/

class Solution {
public:
    int calPoints(vector& ops) {
        int result[1000];
        int index=0;
        int size=ops.size();
        for(int i=0;i0)
                            index--;
                    }
                else if("D"==ops[i])
                    {
                        if(index>0){
                            result[index]=result[index-1]*2;
                            index++;
                        }
                    }
                else if("+"==ops[i])
                    {
                        if(index>=1){
                            result[index]=result[index-1]+result[index-2];
                        }else if(index>0){
                            result[index]=result[index-1];
                        }
                        index++;
                    }
                 else
                    {
                        result[index]=atoi(ops[i].c_str());
                        index++;
                    }
        }
        int sum=0;
        for(int i=0;i