C++ Beginner Friendly Solution #Using vector  ✔🔥😍
Intuition\n Describe your first thoughts on how to solve this problem. \n\n# Approach\n Describe your approach to solving the problem. \n\n# Complexity\n- Time 
# Intuition\n<!-- Describe your first thoughts on how to solve this problem. -->\n\n# Approach\n<!-- Describe your approach to solving the problem. -->\n\n# Complexity\n- Time complexity:\n<!-- Add your time complexity here, e.g. $$O(n)$$ -->\n\n- Space complexity:\n<!-- Add your space complexity here, e.g. $$O(n)$$ -->\n\n# Code\n```\nclass Solution {\npublic:\n  \n    int calPoints(vector<string>& operations) {\n      vector<int>arr(1001,0);\n        int top=-1;\n        int i=0;\n        while(i<operations.size()){\n\n            if(operations[i]=="+"){\n                        int a=arr[top];\n                        top--;\n                        int result=a+arr[top];\n                        top++;\n                        arr[top]=a;\n                        top++;\n                        arr[top]=result;\n                        i++;\n                    }\n                    else if(operations[i]=="D"){\n                        int d=2*arr[top];\n                        top++;\n                        arr[top]=d;\n                        i++;\n                    }\n                    else if(operations[i]=="C"){\n                        arr[top]=0;\n                        top--;\n                        i++;\n                    }\n                    else{\n                        top++;\n                        arr[top]=stoi(operations[i]);\n                        i++;\n                    }\n        }\n\n        int sum=0;\n        int j=0;\n        while(j<arr.size()){\n            sum=sum+arr[j];\n            j++;\n        }\n     \n     return sum;\n    }\n};\n```
['Array', 'Stack', 'C++']