1 #include<cstdio>
 2 #include<cstring>
 3 #include<cmath>
 4 #include<vector>
 5 #include<algorithm>
 6 #define clr(a,m) memset(a,m,sizeof(a))
 7 #define rep(i,a,b) for(int i=a;i<=b;i++)
 8 using namespace std;
 9
10 const int MAXN=1111;
11 const double INF =1e9;
12
13 struct Point{
14     int c;
15     double x,y;
16 }p[MAXN];
17
18 double mp[MAXN][MAXN],f[MAXN][MAXN];
19
20 double d[MAXN];
21 int vis[MAXN],fa[MAXN];
22
23 double prim(int n)
24 {
25     vector<int>q;
26     double cnt=0;
27
28     clr(vis,0);
29     rep(i,1,n)
30         d[i]=INF;
31     d[1]=0;
32     fa[1]=1;
33     rep(i,1,n){
34         int x;
35         double m=INF;
36         rep(y,1,n)
37             if(!vis[y]&&d[y]<m)
38                 m=d[x=y];
39         vis[x]=true;
40         cnt+=mp[fa[x]][x];
41
42         int sz=q.size();
43         rep(j,0,sz-1){
44             f[q[j]][x]=f[x][q[j]]=max(f[q[j]][fa[x]],mp[fa[x]][x]);
45         }
46         q.push_back(x);
47
48         rep(y,1,n)
49             if(!vis[y]&&mp[x][y]<d[y]){
50                 d[y]=mp[x][y];
51                 fa[y]=x;
52             }
53     }
54     return cnt;
55 }
56
57 void print(int n,double cnt)
58 {
59     double m=0;
60     rep(i,1,n)
61         rep(j,i+1,n){
62             double s=cnt-f[i][j];
63             double t=p[i].c+p[j].c;
64             m=max(m,t/s);
65         }
66     printf("%.2f\n",m);
67 }
68
69 int main()
70 {
71     int T,n;
72     scanf("%d",&T);
73     while(T--)
74     {
75         scanf("%d",&n);
76         rep(i,1,n)
77             scanf("%lf%lf%d",&p[i].x,&p[i].y,&p[i].c);
78         rep(i,1,n){
79             mp[i][i]=0;
80             rep(j,i+1,n)
81                 mp[i][j]=mp[j][i]=sqrt((p[i].x-p[j].x)*(p[i].x-p[j].x)+(p[i].y-p[j].y)*(p[i].y-p[j].y));
82         }
83         double cnt=prim(n);
84         print(n,cnt);
85     }
86     return 0;
87 }