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2018-12-05-43-Multiply-Strings.py
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38 lines (33 loc) · 1.27 KB
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# -*- coding: utf-8 -*-
# @Author: 何睿
# @Create Date: 2018-12-05 16:46:00
# @Last Modified by: 何睿
# @Last Modified time: 2018-12-06 11:10:31
class Solution:
def multiply(self, num1, num2):
"""
:type num1: str
:type num2: str
:rtype: str
"""
if num1 == '0' or num2 == '0':
return '0'
lennum1, lennum2 = len(num1), len(num2)
result = [0]*(lennum1+lennum2)
# 共有两层
for i in range(lennum1-1, -1, -1):
for j in range(lennum2-1, -1, -1):
# 首先计算乘积，注意用ASCII码的方式转换为数值
temp = (ord(num1[i])-ord('0'))*(ord(num2[j])-ord('0'))
# 计算所得应和i+j位置求和
_sum = temp+result[i+j+1]
# 第i+j个位置
result[i+j+1] = _sum % 10
# 第i+j-1个位置,此代码为python3，注意使用'//'等号进行运算，例5/2=2.5,5//2=2
result[i+j] += _sum//10
# 将数字转换为字符串
result = [str(i) for i in result]
return ''.join(result[1:]) if result[0] == "0" else ''.join(result)
if __name__ == "__main__":
so = Solution()
print(so.multiply(num1="2", num2='3'))