1943761_ac_0ms_72k.c

北大大牛代码 1240道题的原代码 超级权威

# include <stdio.h>
# include <math.h>
# define PAI 3.141592653589793

int main()
{
	double x1, y1, x2, y2, x3, y3;
	double a, b, c, p, S;

	while(scanf("%lf%lf%lf%lf%lf%lf",&x1,&y1,&x2,&y2,&x3,&y3)==6)
	{
		a = sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2));
		b = sqrt((x1-x3)*(x1-x3) + (y1-y3)*(y1-y3));
		c = sqrt((x3-x2)*(x3-x2) + (y3-y2)*(y3-y2));
		p = (a+b+c)/2;
		S = sqrt(p*(p-a)*(p-b)*(p-c));
		printf("%.2lf\n",0.5*PAI*a*b*c/S);
	}
	return 1;
}