lightOj 1248 Dice (III) 概率公式

详见河北唐山一中 鬲融大神的论文~~~
http://wenku.baidu.com/link?url=fZauRfkVE5NzpJi3a9HAZOe2k3x63U5XIgALMMrwhgRpYLOKuwG_f_BmusI5CGEjFHJXScws1lJupHkcOAFRPlBXQVnCnyEt47RLa8GQY-K

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
using namespace std;
int n;
int main()
{
    int t,i1 = 1,n;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d",&n);
        double ans = 0;
        for(int i=n;i>=1;i--)
            ans+=1.0*n/i;
        printf("Case %d: ",i1);
        i1++;
        printf("%f\n",ans);
    }
    return 0;
}