poj 2249 Binomial Showdown

#include<iostream>            //见poj 1306 Combinations
using namespace std;
int main()
{
    double n,k,i,j;
    while(cin>>n>>k&&n!=0)
    {
        double res=1;
        for(i=n,j=min(n-k,k);j>=1;--i,--j)
        {
            res*=i/j;
        }
        printf("%.0f\n",res);
    }
    return 0;
}



#include<iostream>
using namespace std;
int main()
{
    double n,k,i,j;
    while(cin>>n>>k&&n!=0)
    {
        double r1=1,r2=1;
        for(i=n,j=min(n-k,k);j>=1;--i,--j)
        {
            r1*=i;
            r2*=j;
        }
        printf("%.0f\n",r1/r2);
    }
    return 0;
}