zoj 1199 Point of Intersection

#include <queue>
#include <stack>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <limits.h>
#include <string.h>
#include <string>
#include <algorithm>

using namespace std;

struct point {double x,y;};
point a,b; 
const double eps = 1e-6;
bool dy(double x,double y)	{	return x > y + eps;}	// x > y 
bool xy(double x,double y)	{	return x < y - eps;}	// x < y 
bool dyd(double x,double y)	{ 	return x > y - eps;}	// x >= y 
bool xyd(double x,double y)	{	return x < y + eps;} 	// x <= y 
bool dd(double x,double y) 	{	return fabs( x - y ) < eps;}  // x == y
double disp2p(point a,point b) 
{
	return sqrt( ( a.x - b.x ) * ( a.x - b.x ) + ( a.y - b.y ) * ( a.y - b.y ) );
}
bool c2c_ainb(point a,double r1,point b,double r2)
{
	return xyd(disp2p(a,b),r2 - r1) || xyd(disp2p(a,b),r1 - r2);
}

int main()
{
	int ncases;
	double r1,r2;
	
	scanf("%d",&ncases);
	
	while( ncases-- )
	{
		scanf("%lf%lf%lf",&a.x,&a.y,&r1);
		scanf("%lf%lf%lf",&b.x,&b.y,&r2);
		if( dd(r1,r2) || c2c_ainb(a,r1,b,r2) )
		{
			printf("Impossible.\n");
			continue;
		}
		if( dy(r1,r2) )
		{
			swap(r2,r1);
			swap(a,b);
		}
		double x = (r2*a.x - r1*b.x)/(r2 - r1);
		double y = (r2*a.y - r1*b.y)/(r2 - r1);
		printf("%.2lf %.2lf\n",x,y);
	}
return 0;
}