Expanding Rods

http://poj.org/problem?id=1

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<cmath>
 4 #include<algorithm>
 5 using namespace std;
 6 
 7 const double eps=1e-8;
 8 double n,c,l;
 9 
10 int main()
11 {
12     while(scanf("%lf%lf%lf",&l,&n,&c)&&l!=-1&&n!=-1&&c!=-1){
13         double s=(1+n*c)*l;
14         double low=0,high=0.5*l,mid;
15         while(high-low>eps)
16         {
17             mid=(high+low)/2;
18             double r=(4*mid*mid+l*l)/(8*mid);
19             double ss=2*r*asin(l/(2*r));
20             if(ss<s)
21                 low=mid;
22             else
23                 high=mid;
24         }
25         printf("%.3lf\n",mid);
26     }
27     return 0;
28 }
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posted @ 2013-09-21 19:22  null1019  阅读(199)  评论(0)  编辑  收藏  举报