HUAFU Blog | 43. Multiply Strings

27 Dec 43. Multiply Strings

Posted at 20:54h in Coding by huafu 0 Comments

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Given two non-negative integers num1 and num2 represented as strings, return the product of num1 and num2, also represented as a string.

Note: You must not use any built-in BigInteger library or convert the inputs to integer directly.

Example 1:

Input: num1 = "2", num2 = "3"
Output: "6"

Example 2:

Input: num1 = "123", num2 = "456"
Output: "56088"

Constraints:

1 <= num1.length, num2.length <= 200
num1 and num2 consist of digits only.
Both num1 and num2 do not contain any leading zero, except the number 0 itself.

class Solution:

def multiply(self, num1: str, num2: str) -> str:

if num1 == ‘0’ or num2 ==’0′:

return ‘0’

def strToInt(num):

return_value = 0

for i in num:

return_value = return_value * 10 + (ord(i) – ord(‘0’))

return return_value

def intToStr(num):

return_str = ”

while num:

s = num % 10

num = num // 10

return_str = chr(ord(‘0’)+s) + return_str

return return_str

result = intToStr(strToInt(num1) * strToInt(num2))

return result