Very easy solution (python)
The idea here is to create a list of digits in the num. then sort the digits \nafter sorting, we have a, b, c, d as 4 digits. the answer is ac + bd (or ad + bc)
The idea here is to create a list of digits in the num. then sort the digits \nafter sorting, we have a, b, c, d as 4 digits. the answer is ac + bd (or ad + bc).\n```\nclass Solution:\n    def minimumSum(self, num: int) -> int:\n        list_digits = []\n        while num > 0:\n            list_digits.append(num % 10)\n            num = num // 10\n        \n        a, b, c, d= sorted(list_digits)\n        return 10 * a + c + 10*b + d\n```
['Python', 'Python3']