poj1696 凸包

#include<iostream>
#include<stdio.h>
#include<string.h>
#include<string>
#include<stdlib.h>
#include<cmath>
#include<queue>
#include<algorithm>
using namespace std;
#define rd(x) scanf("%d",&x)
#define rdd(x,y) scanf("%d%d",&x,&y)
#define rddd(x,y,z) scanf("%d%d%d",&x,&y,&z)
#define rds(s) scanf("%s",s)
#define rep(i,n) for(int i=0;i<n;i++)
#define LL long long
const int N = 100;
const int M=5e5+10;
const int inf=1e9;
const double eps=1e-5;
const int MOD=1e9+7;
int n,m;
struct Point{
    double x,y;
    int id;
    Point(){

    }
    Point(double _x,double _y){
        x=_x;y=_y;
    }
    bool operator < (const Point&a) const{
        if(y==a.y) return x<a.x;
        return y<a.y;
    }
};
Point p1,p2,p3,p4;
struct Seg{
    Point s,e;
    Seg(){}
    Seg(Point _s,Point _e){
        s=_s;
        e=_e;
    }
    Seg(double x,double y,double xx,double yy){
        s.x=x;s.y=y;
        e.x=xx;e.y=yy;
    }
};
double cross(Point a,Point b,Point c){
    return (b.x-a.x)*(c.y-a.y)-(b.y-a.y)*(c.x-a.x);
}
double dist(Point a,Point b){
    return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));
}
int sgn(double x){ return x<-eps?-1:x<eps?0:1;}

int inter(Seg a,Seg b){
    Point p1,p2,p3,p4;
    p1=a.s;p2=a.e;
    p3=b.s;p4=b.e;
    if (!(min(p1.x,p2.x)<=max(p3.x,p4.x) &&
    min(p3.x,p4.x)<=max(p1.x,p2.x) &&
    min(p1.y,p2.y)<=max(p3.y,p4.y) &&
    min(p3.y,p4.y)<=max(p1.y,p2.y))) return -1;/*不相交*/
    int d1= sgn(cross(p1,p2,p3));
    int d2=sgn(cross(p1,p2,p4));
    int d3=sgn(cross(p3,p4,p1));
    int d4=sgn(cross(p3,p4,p2));

    if(d1==0 && d2==0) return 0;/*部分重合*/
    if(d1*d2==0 && d3*d4==0) return 1;/*端点重合*/
    if(d1*d2==0 || d3*d4==0) return 2;/*一端点在另一线段非端点的点上*/
    if(d1*d2<0 && d3*d4<0) return 3;/*线段相交*/
    else return -1;
}
Seg seg[100];
Point point[100];
bool vis[100];
int ans[100];
int tot=0;
int pn,sn;
int main()
{
#ifndef ONLINE_JUDGE
freopen("aaa","r",stdin);
#endif
    int T;
    rd(T);
    while(T--){
        rd(n);
        int mi=1;
        Point p0;
        for(int i=1;i<=n;i++){
            scanf("%d%lf%lf",&point[i].id,&point[i].x,&point[i].y);
        }
        sort(point+1,point+1+n);
        p0=point[1];
        for(int i=1;i<=n;i++) vis[i]=false;
        tot=0;
        ans[tot++]=p0.id;
        vis[p0.id]=true;
        Point p1,p2;
        for(int i=2;i<=n;i++){
            int j;
            for(j=1;j<=n;j++) if(!vis[point[j].id]){p1=point[j];break;}
            for(j++;j<=n;j++) {
                      if(!vis[point[j].id] && sgn(cross(p0,p1,point[j]))<0) {
                        p1=point[j];
                    }
            }
            vis[p1.id]=true;

            ans[tot++]=p1.id;
            p0=p1;
        }
        printf("%d ",n);
        for(int i=0;i<tot;i++)
        printf("%d%c",ans[i],i==tot-1?'\n':' ');
    }
    return 0;
}