题目：

题解：

class Solution:def multiply(self, num1: str, num2: str) -> str:if num1 == "0" or num2 == "0":return "0"m, n = len(num1), len(num2)ansArr = [0] * (m + n)for i in range(m - 1, -1, -1):x = int(num1[i])for j in range(n - 1, -1, -1):ansArr[i + j + 1] += x * int(num2[j])for i in range(m + n - 1, 0, -1):ansArr[i - 1] += ansArr[i] // 10ansArr[i] %= 10index = 1 if ansArr[0] == 0 else 0ans = "".join(str(x) for x in ansArr[index:])return ans