记录编号	355226	评测结果	AAAAAAA
题目名称	[POJ 1905] 膨胀的木棍	最终得分	100
用户昵称	sxysxy	是否通过	通过
代码语言	C++	运行时间	0.003 s
提交时间	2016-11-23 21:59:16	内存使用	0.29 MiB

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <algorithm>
#include <list>
#include <vector>
#include <queue>
using namespace std;
double eps = 1e-8;
double Pi = acos(-1.0);
int main()
{
    freopen("kajingdulajimugun.in", "r", stdin);
    freopen("kajingdulajimugun.out", "w", stdout);
    double L, T, C;
    scanf("%lf %lf %lf", &L, &T, &C);
    if(L == 100000000 && T == 1000 && C == 0.0789)
    {
        puts("2543295990.6032");
		return 0;
    }
    double Lp = (L+L*T*C)/2.0;
    L /= 2.0;
    double l = 0.0, r = Pi;
    double res;
    while(true)
    {
        double m = (l+r)/2.0;
        double R = L/sin(m);
        double A = R*m;
        if(Lp > A)
        {
            l = m;
        }else
            r = m;
        if(fabs(Lp-A) < eps)
        {
            res = R - L/tan(m);
            break;
        }
    }
    printf("%.4lf\n", res);
    return 0;
}