ZOJ 1976 --主要用到long long 范围的 组合数计算

#include<stdio.h>
#include<string.h>

long long getac(long long n,long long m)
{
if (m > n / 2) m = n - m;
long long result = 1;
for (long long i = 1; i <= m ; ++i){
result *= (n - i + 1);
result /= i;
}
return result;
}

int main(){
long long n,m;

while (scanf("%lld%lld",&n,&m),n || m){
n += m;
if (n - m < m) m = n - m;
printf("%lld/n",getac(n,m));
}
return 0;
}