#include<stdio.h>#include<math.h>#include<stdlib.h>#include<string.h>#include<algorithm>#include<iostream>#include<vector>#define eps 1e-8using namespace std;struct Point{ double x,y; Point(){} Point(double x0,double y0):x(x0),y(y0){} void Input() { scanf("%lf%lf",&x,&y); }};struct Line{ Point a,b; double inter,k; Line(){} Line(Point a0,Point b0):a(a0),b(b0){}};double Xmult(Point o,Point a,Point b){ return (a.x-o.x)*(b.y-o.y)-(b.x-o.x)*(a.y-o.y);}int Sig(double a){ return a<-eps?-1:a>eps;}int cmp(Line l1,Line l2){ if(!Sig(l1.k-l2.k) && !Sig(l1.inter-l2.inter) && !Sig(l1.a.x-l2.a.x)) return l1.b.x<l2.b.x; if(!Sig(l1.k-l2.k) && !Sig(l1.inter-l2.inter)) return l1.a.x<l2.a.x; if(!Sig(l1.k-l2.k)) return l1.inter<l2.inter; return l1.k<l2.k;}int Count(vector<Line> v){ int n=v.size(); for(int i=0;i<n;i++) { v[i].inter=-(v[i].a.x)*(v[i].b.y-v[i].a.y)/(v[i].b.x-v[i].a.x)+v[i].a.y; v[i].k=(v[i].b.y-v[i].a.y)/(v[i].b.x-v[i].a.x); } sort(v.begin(),v.end(),cmp); int ans=0; for(int i=1;i<n;i++) { if(!Sig(v[i].inter-v[i-1].inter) && !Sig(v[i].k-v[i-1].k) && Sig(v[i].a.x-v[i-1].b.x)<=0) { ans++; v[i].b.x=max(v[i-1].b.x,v[i].b.x);//注意这一步处理将连在一起的线段延长 此时我们只需要记录x延伸的位置而不需要记录y } } return ans;}int cmp1(Line l1,Line l2){ if(!Sig(l1.inter-l2.inter) && !Sig(l1.a.y-l2.a.y)) return l1.b.y<l2.b.y; if(!Sig(l1.inter-l2.inter)) return l1.a.y<l2.a.y; return l1.inter<l2.inter;}int main(){ int n; Point a,b; vector<Line> v; vector<Line> v1; while(scanf("%d",&n) && n) { v.clear(); v1.clear(); for(int i=0;i<n;i++) { a.Input(); b.Input(); if(a.x>b.x) swap(a,b); if(a.x==b.x) v1.push_back(Line(a,b)); else v.push_back(Line(a,b)); } int ans=0; ans=Count(v); for(int i=0;i<v1.size();i++) { v1[i].inter=v1[i].a.x; if(v1[i].a.y>v1[i].b.y) swap(v1[i].a,v1[i].b); } sort(v1.begin(),v1.end(),cmp1); for(int i=1;i<v1.size();i++) if(!Sig(v1[i].inter-v1[i-1].inter) && Sig(v1[i].a.y-v1[i-1].b.y)<=0) { ans++; v1[i].b.y=max(v1[i].b.y,v1[i-1].b.y);//这一步处理同上一步的注释一个道理 } printf("%dn",n-ans); } return 0;}
