POJ 1905 Expanding Rods 二分答案几何

题目：http://poj.org/problem?id=1905

恶心死了，POJ的输出一会要lf，一会要f，而且精度1e-13才过，1e-12都不行，错了一万遍终于对了。

 1 #include 
 2 #include 
 3 
 4 int main()
 5 {
 6     double l, n, c, r;
 7     while(scanf("%lf %lf %lf", &l, &n, &c) != EOF)
 8     {
 9         if(l < 0 && n < 0 && c < 0)break;
10         double arc = (1 + n*c) * l;
11         double low = 0, high = acos(-1.0) / 2;
12         while(high-low > 1e-13)
13         {
14             double mid = (high+low) / 2;
15             r = l/2 / sin(mid);
16             if(r * mid < arc / 2)
17             {
18                 low = mid;
19             }
20             else
21             {
22                 high = mid;
23             }
24         }
25         printf("%.3lf\n", r-r*cos(low));
26     }
27     return 0;
28 }

View Code

 

转载于:https://www.cnblogs.com/wolfred7464/p/3388465.html