hdu 2289 二分求水的高度

题意:给出杯子的参数,和水的体积,求水的高度,....这二分?难道水不一定是从杯子底下开始的?

#include<iostream>#include<cmath>#define Pi 3.14159265using namespace std;double r,R,H,V,a,b,mid;double get_V(double h){  double tr;  tr=(h/H)*(R-r)+r;  return 1/3.0*Pi*h*(tr*tr+r*r+tr*r);}int main(){  int T;  scanf("%d",&T);  while(T--)  {    scanf("%lf%lf%lf%lf",&r,&R,&H,&V);    a=0;b=H;    while(fabs(b-a)>1e-10)    {      mid=(a+b)/2.0;      if(get_V(mid)>V) b=mid-(1e-10);      else a=mid+(1e-10);    }    printf("%.6f\n",mid);  }  system("pause");}