Cup HDU 2289

 1 #include <stdio.h>
 2 #include <math.h>
 3 
 4 const double Pi=acos(-1.0);
 5 double h0;
 6 
 7 double VV(double r,double R,double H)
 8 {
 9     return Pi*H*(R*R+r*r+R*r)/3.0;
10 }
11 
12 bool C(double r,double h,double V)
13 {
14     double R=r*(h0+h)/h0;
15     double v=Pi*h*(R*R+r*r+R*r)/3.0;
16     if(v<=V)
17         return true;
18     else
19         return false;
20 }
21 
22 bool C2(double r,double h,double V)
23 {
24     double v=r*r*Pi*h;
25     if(v<=V)
26         return true;
27     else
28         return false;
29 }
30 
31 int main()
32 {
33     int T;
34     scanf("%d",&T);
35     while(T--)
36     {
37         double r,R,H,V;
38         scanf("%lf %lf %lf %lf",&r,&R,&H,&V);
39         if(VV(r,R,H)<=V)
40             printf("%.6lf\n",H);
41         else
42         {
43             double lb=0,ub=H;
44             if(R!=r)
45             {
46                 h0=r*H/(R-r);
47                 for(int i=1;i<=100;i++)
48                 {
49                     double mid=(lb+ub)/2.0;
50                     if(C(r,mid,V))
51                         lb=mid;
52                     else
53                         ub=mid;
54                 }
55                 printf("%.6lf\n",lb);
56             }
57             else
58             {
59                 for(int i=1;i<=100;i++)
60                 {
61                     double mid=(lb+ub)/2.0;
62                     if(C2(r,mid,V))
63                         lb=mid;
64                     else
65                         ub=mid;
66                 }
67                 printf("%.6lf\n",lb);
68             }
69             
70         }
71     }
72     return 0;
73 }