poj 1671 Rhyme Schemes

这是一道对斯特林数的运用：s[n][k] = s[n-1][k-1] + k*[n-1][k];

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<algorithm>
#include<cmath>
#include<queue>
#include<set>
#include<map>
#include<cstring>
#include<vector>
#include<string>
#define LL long long
using namespace std;
double c[124][124];
void Init( )
{
    c[0][0] = 1.0;
    for( int i = 1 ; i <=100; i ++ )
         for( int j = 0 ; j <=i ; j ++ )
         {
              if( j==0 ) c[i][j] = 0;
              else c[i][j] = c[i-1][j-1] + 1.0*j*c[i-1][j];
         }    
}
int main(  )
{
     Init();
     int n;
     while( scanf( "%d",&n ),n )
     {
          double ans=0.0;
          for( int i = 0 ;  i <= n ; i ++ )
               ans += c[n][i];
          printf( "%d %.0f\n",n,ans );        
     }
    //system( "pause" );
    return 0;
}