三分 POJ3737 

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cmath>
 4 
 5 using namespace std;
 6 
 7 double pi=acos(-1.0);
 8 double s;
 9 
10 double f(double x)
11 {
12     return pi*x*x*sqrt((s-pi*x*x)/(pi*x)*(s-pi*x*x)/(pi*x)-x*x)/3;
13 }
14 
15 bool test(double tl,double tr)
16 {
17     if(f(tl)<f(tr))
18         return true;
19     else
20         return false;
21 }
22 
23 int main()
24 {
25     while(scanf("%lf",&s)!=EOF)
26     {
27         double l=0;
28         double r=sqrt(s/(2*pi));
29         while(r-l>1e-8)
30         {
31             double tl=l+(r-l)/3;
32             double tr=r-(r-l)/3;
33             if(test(tl,tr))
34             {
35                 l=tl;
36             }
37             else
38             {
39                 r=tr;
40             }
41         }
42         double h=sqrt((s-pi*l*l)/(pi*l)*(s-pi*l*l)/(pi*l)-l*l);
43         printf("%.2lf\n",f(l));
44         printf("%.2lf\n",h);
45         printf("%.2lf\n",l);
46     }
47     return 0;
48 }
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posted @ 2015-08-23 13:16  相儒以沫  阅读(166)  评论(0)    收藏  举报