# Description

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.

The original problem is here.

The original code is here.

# My Solution

I solve this problem in C++, as below:

``````/*
*Multiply Strings
*Author: shuaijiang
*Email: zhaoshuaijiang8@gmail.com
*/
#include<iostream>
#include<math.h>
#include<vector>
#include<string>
#include<stdlib.h>
using namespace std;

class Solution {
public:
string multiply(string num1, string num2) {
int size1 = num1.size();
int size2 = num2.size();
vector<int> result(size1+size2,0);
int k = size1+size2-2;
for(int i=0;i<size1;i++){
int n1 = num1[i]-'0';
for(int j=0;j<size2;j++){
int n2 = num2[j]-'0';
result[k-i-j] += n1 * n2;
}
}
int carries = 0;
for(int i=0;i<size1+size2;i++){
result[i] += carries;
if(result[i] > 9){
carries = result[i]/10;
result[i] = result[i] % 10;
}
else
carries = 0;
}
int i = size1+size2-1;
while(result[i] == 0)
i--;
string str;
for(int j=i;j>=0;j--){
str.push_back(result[j]+'0');
}
if(str == "")
str.push_back('0');
return str;
}
};
``````

# Note

To simplify the problem, reference to blog.