杭电2048

 1 #include <stdio.h>
 2 float fac(int a)//阶乘
 3 {
 4     if(a==0)
 5         return 1;
 6     else
 7         return a*fac(a-1);
 8 }
 9 int main()
10 {
11     int t,i,num;
12     float p[50]={0,0,1};
13     scanf("%d",&t);
14     i=3;
15     while(t--)
16     {
17         scanf("%d",&num);
18         for(;i<=num;i++)
19             p[i]=(i-1)*(p[i-1]+p[i-2]);
20         printf("%.2f%%\n",p[num]*100/fac(num));
21     }
22     return 0;
23 }