ZJNU 1262 - 电灯泡——中高级

 1 /*
 2 Written By StelaYuri
 3 */
 4 #include<stdio.h>
 5 double H,h,D;
 6 double len(double lh){
 7     return lh+D*(h-lh)/(H-lh);
 8 }
 9 int main(){
10     int T;
11     double l,r,m1,m2;
12     scanf("%d",&T);
13     while(T--){
14         scanf("%lf%lf%lf",&H,&h,&D);
15         l=0;r=h;
16         while(r-l>=1e-5){
17             m1=l+(r-l)/3.0;//三分左
18             m2=l+(r-l)/1.5;//三分右
19             if(len(m1)>len(m2))
20                 r=m2;
21             else
22                 l=m1;
23         }
24         printf("%.3lf\n",len(l));
25     }
26     
27     return 0;
28 }