POJ 1306 Combinations

// 求 C[n][m]

// 组合公式 C[i][j]=C[i-1][j-1]+C[i-1][j];

#include <iostream>

#include <string>

#include<sstream>

#include <cmath>

#include <map>

#include <stdio.h>

#include <string.h>

#include <algorithm>

using namespace std;

#define  LL long long

LL C[123][123];

int main()

{

   int i,j;

   for(i=0;i<=100;i++) C[i][0]=1;

   for(i=1;i<=100;i++)

     for(j=1;j<=i;j++)

       C[i][j]=C[i-1][j-1]+C[i-1][j];

   int n,k;

   while(scanf("%d %d",&n,&k),n|k)

   {

      printf("%d things taken %d at a time is %lld exactly.\n",n,k,C[n][k]);

   }

   return 0;

}