7.cpp

杭电 acm部分代码 有兴趣的可以下载 谢谢

#include<stdio.h>
#include<math.h>
double f(double a1,double b)
{
	return a1*a1*(acos(2.0*b*b/a1*a1-1)-sin(acos(2*b*b/a1*a1-1)))/2.0;
}

int main()
{
	double a1,a2,x1,x2,y1,y2,b,c,x,y;
	while(scanf("%lf%lf%lf%lf%lf%lf",&x1,&y1,&a1,&x2,&y2,&a2)!=EOF)
	{
		x=x1-x2;
		y=y2-y1;
		b=(x*x+y*y+a1*a1-a2*a2)/2.0*sqrt(x*x+y*y);
		c=(x*x+y*y-a1*a1+a2*a2)/2.0*sqrt(x*x+y*y);
		printf("%.3lf\n",f(a1,b)+f(a2,c));
	}
	return 0;
}