版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/leekerian/article/details/82668582
三分
#include <iostream>
#include <cmath>
#include <cstdio>
using namespace std;
const double eps=1e-8;
double S;
const double PI=acos(-1.0);
double f(double x)
{
double ans=sqrt((S/(PI*x)-x)*(S/(PI*x)-x)-x*x)*PI*x*x/3.0;
return ans;
}
int main()
{
while(scanf("%lf",&S)!=EOF)
{
double l=0.0;
double r=sqrt(S/PI);
while(r-l>eps)
{
double lmid=l+(r-l)/3;
double rmid=r-(r-l)/3;
if(f(lmid)>=f(rmid))
r=rmid;
else
l=lmid;
}
printf("%.2lf\n",f(l));
printf("%.2lf\n",sqrt((S/(PI*l)-l)*(S/(PI*l)-l)-l*l));
printf("%.2lf\n",l);
}
return 0;
}