43 - Multiply Strings
Written on November 15, 2015
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Given two numbers represented as strings, return multiplication of the numbers as a string.
class Solution:
def multiply(self, num1: str, num2: str) -> str:
ret = [0] * (len(num1) + len(num2))
for i in reversed(range(len(num1))):
for j in reversed(range(len(num2))):
num = int(num1[i]) * int(num2[j]) + ret[i + j + 1]
ret[i + j + 1] = num % 10
ret[i + j] += num // 10
start = 0
while start < len(ret):
if ret[start] != 0:
break
start += 1
return "".join(map(str, ret[start:])) or "0"