Easy Approach
cpp\nclass Solution {\npublic:\n    int minimumSum(int num) {\n        \n        int a, b, c, d;\n        vector<int> arr;\n        \n        a = num%10, num/=1
```cpp\nclass Solution {\npublic:\n    int minimumSum(int num) {\n        \n        int a, b, c, d;\n        vector<int> arr;\n        \n        a = num%10, num/=10;\n        b = num%10, num/=10;\n        c = num%10, num/=10;\n        d = num%10, num/=10;\n        \n        arr = {a, b, c, d};\n        sort(arr.begin(), arr.end());\n        \n        return (10*arr[0]+arr[2])+(10*arr[1]+arr[3]);\n    }\n};\n```
['C']