leetcode-25双周赛-改变一个整数能得到的最大差值

class Solution:
    def maxDiff(self, num: int) -> int:
        maxn, minn = num, num
        for i in range(10):
            s = str(num).replace(str(i), ‘9‘)
            maxn = max(int(s), maxn)
            s = str(num).replace(str(i),‘0‘)
            if s[0] != ‘0‘:
                minn = min(int(s), minn)
            s = str(num).replace(str(i), ‘1‘)
            minn = min(int(s), minn)
        return maxn - minn