poj 1410 计算几何

  1 /**

  2 注意： 千万得小心。。就因为一个分号，调了一个晚上。。。

  3 **/

  4 #include <iostream>

  5 #include <algorithm>

  6 using namespace std;

  7 struct point {

  8     int x,y;

  9 };

 10

 11 struct line{

 12     point a;

 13     point b;

 14 };

 15 line l,lt;//l 直线 lt 矩形的边

 16 int x1,x2,y1,y2;

 17

 18 int mmax(double a,double b){

 19     return a>b?a:b;

 20 }

 21

 22 int mmin(double a,double b){

 23     return a<b?a:b;

 24 }

 25

 26 double dir(point o,point p,point   q){

 27     return (p.x-o.x)*(q.y-o.y)-(p.y-o.y)*(q.x-o.x);

 28 }

 29

 30 int on_border(point o,point p,point q){

 31     if(mmin(o.x,p.x)<=q.x&&q.x<=mmax(o.x,p.x)&&mmin(o.y,p.y)<=q.y&&q.y<=mmax(o.y,p.y))

 32         return 1;

 33     else

 34         return 0;

 35 }

 36

 37 int cross(line v,line t){

 38     double a,b,c,d;

 39     a = dir(t.a,t.b,v.a);

 40     b = dir(t.a,t.b,v.b);

 41     c = dir(v.a,v.b,t.a);

 42     d = dir(v.a,v.b,t.b);

 43     if(a*b<0&&c*d<0)

 44         return 1;

 45     if(!a&&on_border(t.a,t.b,v.a))

 46         return 1;

 47     if(!b&&on_border(t.a,t.b,v.b))

 48         return 1;

 49     if(!c&&on_border(v.a,v.b,t.a))

 50         return 1;

 51     if(!d&&on_border(v.a,v.b,t.b))

 52         return 1;

 53     return 0;

 54 }

 55

 56 int main()

 57 {

 58     int n;

 59     cin>>n;

 60     while(n--){

 61         cin>>l.a.x>>l.a.y>>l.b.x>>l.b.y;

 62         cin>>x1>>y1>>x2>>y2;

 63         if(x1>x2)

 64             swap(x1,x2);

 65         if(y1<y2)

 66             swap(y1,y2);

 67         int flag =0;

 68         lt.a.x = x1;

 69         lt.a.y=y1;

 70         lt.b.x = x2;

 71         lt.b.y =y1;

 72         if(cross(l,lt))

 73             flag =1;

 74         else{

 75             lt.a.x=x2;

 76             lt.a.y=y1;

 77             lt.b.x=x2;

 78             lt.b.y=y2;

 79             if(cross(l,lt))

 80                 flag =1;

 81             else{

 82                 lt.a.x=x1;

 83                 lt.a.y=y2;

 84                 lt.b.x=x2;

 85                 lt.b.y=y2;

 86                 if(cross(l,lt))

 87                     flag =1;

 88                 else{

 89                     lt.a.x = x1;

 90                     lt.a.y=y1;

 91                     lt.b.x=x1;

 92                     lt.b.y=y2;

 93                     if(cross(l,lt))

 94                         flag =1;

 95                 }

 96             }

 97         }

 98         if(flag)

 99             cout<<"T"<<endl;

100         else{

101             if((x1<mmin(l.a.x,l.b.x))&&(mmax(l.a.x,l.b.x)<x2)&&(y2<mmin(l.a.y,l.b.y))&&(mmax(l.a.y,l.b.y)<y1))

102                 cout<<"T"<<endl;

103             else

104                 cout<<"F"<<endl;

105         }

106     }

107     return 0;

108 }

poj 1410 计算几何