poj3673（Cow Multiplication）

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

#include<iostream>
#include<string.h>
using namespace std;
int main()
{
    int sum=0,l1=0,l2=0;
    char a[10]={0},b[10]={0};
    cin>>a>>b;
    l1=strlen(a);
    l2=strlen(b);
    for(int i=0;i<l1;i++)
    {
        for(int j=0;j<l2;j++)
        {
            sum+=(a[i]-'0')*(b[j]-'0');
        }
    }
    cout<<sum<<endl;
    return 0;
}

这个题用C++交#include<string>就AC,G++就编译错误。奇怪

后来改用#include<string.h>G++就可以了；不知道什么原因不过下回这么写吧