Leetcode之Multiply Strings

字符串相乘，题目如下：

Given two numbers represented as strings, return multiplication of the numbers as a string.

Note: The numbers can be arbitrarily large and are non-negative.

根据上面的字符串的相乘，变成数组相乘。

C++ Code

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class Solution { public: string multiply(string s1, string s2) { if(s1 == "0" || s2 == "0") return "0"; int len1 = s1.length(); int len2 = s2.length(); int len3 = len1 + len2; vector<int> num1(len1, 0); vector<int> num2(len2, 0); vector<int> num3(len1 + len2, 0); for(int i = 0; i < len1; i++) { num1[i] = s1[i] - '0'; } for(int i = 0; i < len2; i++) { num2[i] = s2[i] - '0'; } for(int i = 0; i < len1; i++) { for(int j = 0; j < len2; j++) { num3[i + j + 1] += num1[i] * num2[j]; } } string ss = ""; for(int i = len3 - 1; i >= 0; i--) { if(i > 0) { num3[i - 1] += num3[i] / 10; } num3[i] = num3[i] % 10; ss = char(num3[i] + '0') + ss; } ss = ss[0] == '0' ? ss.substr(1) : ss; return ss; } };