poj 1066 Treasure Hunt

http://poj.org/problem?id=1066

 #include <cstdio>
 #include <cstring>
 #include <cmath>
 #include <cstdlib>
 #include <algorithm>
 #define maxn 500000
 using namespace std;

 const double eps=1e-;
 const int inf=<<;
 int t1,t2,t3,t4,t5,c;

 int cmp(double x)
 {
     if(fabs(x)<eps) return ;
     if(x>) return ;
     return -;
 }

 struct point
 {
     double x,y;
     point() {}
     point(double a,double b):x(a),y(b) {}
     friend point operator -(const point &a,const point &b)
     {
         return point(a.x-b.x,a.y-b.y);
     }
     friend point operator *(const point &a,const double &b)
     {
         return point(a.x*b,a.y*b);
     }
     friend point operator /(const point &a,const double &b)
     {
         return point(a.x/b,a.y/b);
     }
 } p[maxn];
 point m[][];

 int cmp1(const point &a,const point &b)
 {
     return a.x<b.x;
 }

 int cmp2(const point &a,const point &b)
 {
     return a.y<b.y;
 }

 struct line
 {
     point a,b;
     line() {}
     line(point x,point y):a(x),b(y) {};
 } ll[maxn];

 double det(const point &a,const point &b)
 {
     return a.x*b.y-a.y*b.x;
 }

 bool segment(point a1,point a2,point b1,point b2)
 {
     double c1=det(a2-a1,b1-a1),c2=det(a2-a1,b2-a1);
     double c3=det(b2-b1,a1-b1),c4=det(b2-b1,a2-b1);
     return cmp(c1)*cmp(c2)<&&cmp(c3)*cmp(c4)<;
 }

 void make(double x,double y)
 {
     if(y==)
     {
         m[][t1].x=x;
         m[][t1++].y=y;
     }
     else if(y==)
     {
         m[][t2].x=x;
         m[][t2++].y=y;
     }
     else if(x==)
     {
         m[][t3].x=x;
         m[][t3++].y=y;
     }
     else if(x==)
     {
         m[][t4].x=x;
         m[][t4++].y=y;
     }
 }

 void inti()
 {
     for(int i=; i<=t1; i++)
     {
         p[c].x=(m[][i].x+m[][i-].x)/;
         p[c++].y=;
     }
     for(int i=; i<=t3; i++)
     {
         p[c].y=(m[][i].y+m[][i-].y)/;
         p[c++].x=;
     }
     for(int i=; i<=t2; i++)
     {
         p[c].x=(m[][i].x+m[][i-].x)/;
         p[c++].y=;
     }
     for(int i=; i<=t4; i++)
     {
         p[c].y=(m[][i].y+m[][i-].y)/;
         p[c++].x=;
     }
 }
 int main()
 {
     int T;
     while(scanf("%d",&T)!=EOF)
     {
         int n=T;
         double x1,y1,x2,y2;
         t1=,t2=,t3=,t4=,t5=;
         c=;
         while(T--)
         {
             scanf("%lf%lf%lf%lf",&x1,&y1,&x2,&y2);
             make(x1,y1);
             make(x2,y2);
             point st(x1,y1);
             point st1(x2,y2);
             ll[t5].a=st;
             ll[t5++].b=st1;
         }
         m[][].x=;
         m[][].y=;
         m[][t1].x=;
         m[][t1].y=;
         m[][t3].x=;
         m[][t3].y=;
         m[][].x=;
         m[][].y=;
         m[][].x=;
         m[][].y=;
         m[][t2].x=;
         m[][t2].y=;
         m[][].x=;
         m[][].y=;
         m[][t4].x=;
         m[][t4].y=;
         sort(m[],m[]+t1+,cmp1);
         sort(m[],m[]+t2+,cmp1);
         sort(m[],m[]+t3+,cmp2);
         sort(m[],m[]+t4+,cmp2);
         inti();
         point pp,p1;
         scanf("%lf%lf",&pp.x,&pp.y);
         int ans=inf;
         for(int i=; i<c; i++)
         {
             line l1(p[i],pp);
             int ans1=;
             for(int j=; j<t5; j++)
             {
                 if(segment(l1.a,l1.b,ll[j].a,ll[j].b)) ans1++;
             }
             ans=min(ans,ans1);
         }
         if(n==)
         {
             ans=;
         }
         printf("Number of doors = %d\n",ans+);
     }
     return ;
 }