leetcode1281

class Solution:
    def subtractProductAndSum(self, n: int) -> int:
        s = str(n)
        mul,sums = 1, 0
        for i in range(len(s)):
            cur = int(s[i])
            mul *= cur
            sums += cur
        return mul - sums

一次循环，同时记录乘积与加和。循环结束，两值再相减。