/****************************************************


用64可以这样写
****************************************************/

#include<iostream>
using namespace std;


 __int64 kin_Cnk(int n,int k){
	__int64 sum1 = 1;
	__int64 sum2 = 1;
	int time = k;
	while(time--){
	   sum1 *= n--;
	   if(sum1%k==0){
		   sum1 /= k--;
	   }
	} 
	while(k)
		sum2 *= k--; 
	return sum1 / sum2;
}

int main()
{
int n,k,temp;
__int64 sum;
while(scanf("%d%d",&n,&k)){
   if(!n && !k) break;
   if(k> n/2) temp = n - k;
   else temp = k;
   sum = kin_Cnk(n,temp);
   printf("%d things taken %d at a time is %I64d exactly.\n"
			,n,k,sum);
}
return 0;
}
 

• Re:所以说数据不弱，题弱 (750) kin2141539 2008-09-12 18:29:16
• Re:算错了，连100 12这种数据都不可能出现 这已经是结果是64位的数据了 (750) kin2141539 2008-09-12 18:32:04