hdu 1221 Rectangle and Circle（矩形與圓焦點問題）

求平面內矩形與圓是否有焦點，分別求出圓點到矩形四個邊的交點，判斷交點是否在邊上

#include<iostream>#include<cmath>using namespace std;bool xiao(double x1,double x2){if(x1-x2<1e-8)return true;else false;}int main(){int num;double x,y,r,x1,y1,x2,y2;double zx1,zy1,zx2,zy2;cin>>num;for(int ii=0;ii<num;ii++){cin>>x>>y>>r>>zx1>>zy1>>zx2>>zy2;x1=zx1<zx2?zx1:zx2;x2=zx1<zx2?zx2:zx1;y1=zy1<zy2?zy1:zy2;y2=zy1<zy2?zy2:zy1;double rP=r*r;bool flag=false;if(rP-(x1-x)*(x1-x)>=0)  //左面{double  kai=sqrt(rP-(x1-x)*(x1-x));double t1=kai+y;double t2=0-kai+y;if((t1<=y2&&t1>=y1)||(t2<=y2&&t2>=y1))flag=true;}if(flag==false&&rP-(x2-x)*(x2-x)>=0) //右面{double  kai=sqrt(rP-(x2-x)*(x2-x));double t1=kai+y;double t2=0-kai+y;if((t1<=y2&&t1>=y1)||(t2<=y2&&t2>=y1))flag=true;}if(flag==false&&rP-(y1-y)*(y1-y)>=0) //下面{double  kai=sqrt(rP-(y1-y)*(y1-y));double t1=kai+x;double t2=0-kai+x;if((t1<=x2&&t1>=x1)||(t2<=x2&&t2>=x1))flag=true;}if(flag==false&&rP-(y2-y)*(y2-y)>=0)  //上面{double  kai=sqrt(rP-(y2-y)*(y2-y));double t1=kai+x;double t2=0-kai+x;if((t1<=x2&&t1>=x1)||(t2<=x2&&t2>=x1))flag=true;}if(flag)cout<<"YES"<<endl;else cout<<"NO"<<endl;}}