POJ 3673：Cow Multiplication

Cow Multiplication

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 12210		Accepted: 8509

Description

Bessie is tired of multiplying pairs of numbers the usual way, so she invented her own style of multiplication. In her style, A*B is equal to the sum of all possible pairwise products between the digits of A andB. For
example, the product 123*45 is equal to 1*4 + 1*5 + 2*4 + 2*5 + 3*4 + 3*5 = 54. Given two integers A and B (1 ≤ A, B ≤ 1,000,000,000), determine A*B in Bessie's style of multiplication.

Input

* Line 1: Two space-separated integers: A and B.

Output

* Line 1: A single line that is the A*B in Bessie's style of multiplication.

Sample Input

123 45

Sample Output

54

还是水题。。。字符串按位乘，再相加。
代码：

#include <iostream>
#include <cmath>
#include <algorithm>
#include <string>
#include <cstring>
using namespace std;

int main()
{
string m,n;
cin>>m>>n;

int i,j,result=0;
for(i=0;i<m.length();i++)
{
for(j=0;j<n.length();j++)
{
result += (m[i]-'0')*(n[j]-'0');
}
}
cout<<result<<endl;
return 0;
}