代码：#include <stdio.h>#define MAX 100100struct Point{double x ,y ;Point operator-(Point p){Point ans ;ans.x = x-p.x ;ans.y = y-p.y ;return ans ;}};struct Segment{Point s , e ;bool cover ;}seg[MAX];double min(double x , double y){return x>y?y:x ;}double max(double x , double y){return x>y?x:y ;}bool quickExclude(const Segment &a , const Segment &b){double minRX = min(a.s.x,a.e.x) , minRY = min(a.s.y,a.e.y) ;double maxRX = max(a.s.x,a.e.x) , maxRY = max(a.s.y,a.e.y) ;double minTX = min(b.s.x,b.e.x) , minTY = min(b.s.y,b.e.y) ;double maxTX = max(b.s.x,b.e.x) , maxTY = max(b.s.y,b.e.y) ;if(max(minTX,minRX)>min(maxTX,maxRX) && max(minTY,minRY)>min(maxTY,maxRY)){return false ;}return true ;}double f(Point p1 , Point p2){return p1.x*p2.y-p1.y*p2.x ;}bool ifIntersect(Segment &a , Segment &b){if(quickExclude(a,b)){if(f(a.s-b.s,b.e-b.s)*f(b.e-b.s,a.e-b.s)>=0 &&f(b.s-a.s,a.e-a.s)*f(a.e-a.s,b.e-a.s)>=0 ){return true ;}}return false ;}int main(){int n ;while(~scanf("%d",&n) && n){for(int i = 0 ; i < n ; ++i){scanf("%lf%lf%lf%lf",&seg[i].s.x,&seg[i].s.y,&seg[i].e.x,&seg[i].e.y) ;seg[i].cover = false ;}for(int i = 0 ; i < n ; ++i) //注意只能这样写！！下面有超时的代码例子 {for(int j = i+1 ; j < n ; ++j){if(ifIntersect(seg[i],seg[j])){seg[i].cover = true ;break ;}}}/* 超时的代码！！！for(int i = 0 ; i < n ; ++i){for(int j = i+1 ; j < n ; ++j){if(!seg[i].cover){if(ifIntersect(seg[i],seg[j])){seg[i].cover = true ;break ;}}}}*/int i = 0;for(i = 0 ; i < n ; ++i){if(!seg[i].cover){printf("Top sticks: %d",i+1) ;break ;}}for(i=i+1; i < n ; ++i){if(!seg[i].cover){printf(", %d",i+1) ;}}puts(".") ;}return 0 ;}与君共勉
，更有一种逍遥，浑然忘我，与大自然交融的境界令人心弛神往。
