poj3673,

## Problem:

Cow Multiplication

 Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 7792 Accepted: 5135

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 and B. 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`

Source
USACO 2008 February Bronze

## Source Code:

//Sun 31 Jan 2010 02:03:36 PM CST
#include <iostream>
#include <string>
#include <vector>

using namespace std;

int main()
{
string s1;
string s2;
cin >> s1 >> s2;
int sum1 = 0;
int sum2 = 0;
int sz1 = s1.size();
int sz2 = s2.size();
for(int i=0; i<sz1; i++)
{
sum1 += s1[i]-'0';
}
for(int i=0; i<sz2; i++)
{
sum2 += s2[i]-'0';
}
cout << sum1*sum2 << endl;
return 0;
}
[/sourcecode]