1837805_ac_0ms_44k.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 3.141592653

int main()
{
 double x1, y1, r1, a1, x2, y2, r2, a2, d, s;
 
 scanf("%lf%lf%lf%lf%lf%lf",&x1,&y1,&r1,&x2,&y2,&r2);
 
 d = sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
 
 if(d >= r1 + r2)
 {printf("0.000\n");return 0;}
 if(d <= fabs(r1-r2))
 {printf("%.3lf\n",PAI*pow(r1<r2?r1:r2,2));return 0;}
 
   a1 = 2*acos((r1*r1+d*d-r2*r2)/(2*r1*d));
   a2 = 2*acos((r2*r2+d*d-r1*r1)/(2*r2*d));

   s = 0.5*a1*r1*r1+0.5*a2*r2*r2-0.5*sin(a1)*r1*r1-0.5*sin(a2)*r2*r2;
   printf("%.3lf\n",s);return 0;
}