1 //2653 2 #include <stdio.h> 3 #include <iostream> 4 #include <math.h> 5 #include <string.h> 6  7 using namespace std ; 8  9 struct point10 {11     double x,y ;12 }p[200100];13 struct line14 {15     point a,b ;16 }L[101000];17 int ans[1100] ;18 19 double multi(point a,point b,point c)20 {21     return ((a.x-c.x) * (b.y-c.y) - (b.x-c.x)*(a.y-c.y)) ;22 }23 bool intersect(point a,point b,point c,point d)//非规范相交24 {25     if(max(a.x,b.x) < min(c.x,d.x) || max(a.y,b.y) < min(c.y,d.y) || max(c.x,d.x) < min(a.x,b.x) || max(c.y,d.y) < min(a.y,b.y))26         return false ;27     if(multi(c,b,a) * multi(b,d,a) < 0 || multi(a,d,c)*multi(d,b,c) < 0) return false ;28     return true ;29 }30 int main()31 {32     int n ;33     while(~scanf("%d",&n))34     {35         if(n == 0)  break ;36         for(int i = 1 ; i <= n ; i++)37             scanf("%lf %lf %lf %lf",&L[i].a.x,&L[i].a.y,&L[i].b.x,&L[i].b.y) ;38         int cnt = 0 ;39         for(int i = 1 ; i < n ; i++)40         {41             bool flag = true ;42             for(int j = i+1 ;j <= n ; j++)43             {44                 if(intersect(L[i].a,L[i].b,L[j].a,L[j].b))45                 {46                     flag = false ;47                     break ;48                 }49             }50             if(flag) ans[cnt ++] = i ;51         }52         printf("Top sticks: ") ;53         for(int i = 0 ; i < cnt ; i++)54         {55             printf("%d, ",ans[i]) ;56         }57         printf("%d.\n",n) ;58     }59     return 0 ;60 }