43.字符串相乘

任务描述

• 
  思路
• 将字符串转为整数型列表，算出乘积后再用str()转为字符串输出

代码实现

class Solution:
    def multiply(self, num1: str, num2: str) -> str:
        l1 = [int(x) for x in num1]
        l2 = [int(x) for x in num2]
        a = len(l1)
        b = len(l2)
        sum1 = 0
        sum2 = 0
        
        for i in range(a):
            sum1 += l1[i]*10**(a-1-i)
        
    
        for i in range(b):
            sum2 += l2[i]*10**(b-1-i)
        
        return str(sum1*sum2)