C++ , 100% faster, 0ms, Using Stack , Easy to understand
\nclass Solution {\npublic:\n    int calPoints(vector<string>& ops) {\n        stack <int> st;\n        int sum = 0;\n        \n        for(int i = 0; i < ops.s
```\nclass Solution {\npublic:\n    int calPoints(vector<string>& ops) {\n        stack <int> st;\n        int sum = 0;\n        \n        for(int i = 0; i < ops.size(); i++){\n                \n                if(ops[i] == "+"){\n                        \n                        int val1,val2;\n                        val1 = st.top();\n                        st.pop();\n                        val2 = st.top();\n                        st.pop();\n                        sum += (val1 + val2);\n                        st.push(val2);\n                        st.push(val1);\n                        st.push(val2 + val1);\n                }\n                        else if(ops[i] == "D"){    \n                        int val = st.top();\n                        st.push( val*2 );\n                        sum += 2*val;\n                        }\n                        else if(ops[i] == "C"){                \n                        sum -= st.top();\n                        st.pop();\n                }\n                else \n                    st.push(stoi(ops[i])),sum += stoi(ops[i]);\n        }\n        return sum;\n    }\n};\n```
['Stack', 'C']