2748260_ac_15ms_88k.cpp

北大大牛代码 1240道题的原代码 超级权威

#include <stdio.h>
#include <math.h>

double r = 3950;
double R = 432000;
double D = 92900000;
double pi = acos(-1.0);
double L = sqrt(D * D + R * R - r * r);
double theta1 = atan(R / D);
double theta2 = atan(L / r);
double beta1 = theta1 + theta2;

double beta_t(double t)
{
    return beta1-2*pi*t/24.0/3600.0;
}

int main()
{
	double t;

	while(scanf("%lf",&t)==1)
	{
		double beta = beta_t(t);
        double d = (D*cos(beta)-r)/sin(beta);
        double angle;
        if (d<=-R)
            angle = -pi*0.5;
        else if(d>-R&&d<R)
            angle = asin(d/R);
        else
            angle = pi*0.5;
        printf("%lf\n",0.5+angle/pi+d*cos(angle)/pi/R);
	}
	return 0;
}