01分数规划的题目；
由于是完全图，所以求最小生成树的时候要使用prime算法。
否则的话很容易就超时了。
#include <iostream>
#include<algorithm>
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<queue>
#include<stack>
#include<math.h>
using namespace std;
#define maxm 1100*1100
#define maxn 1100
#define eps 0.000001
#define zero(x) ((fabs(x)<eps?0:x))
#define INF 99999999
struct point
{int x;int y;int h;
}p[maxn];
double dist(int x,int y)
{double xx=0;xx=(p[x].x-p[y].x)*(p[x].x-p[y].x);xx+=(p[x].y-p[y].y)*(p[x].y-p[y].y);xx=xx*1.0;return sqrt(xx);
}
struct list
{double h;double l;double s;friend bool operator < (const list &a,const list &b){return a.s<b.s;}
}maps[maxn][maxn];
int m,n;
double prime(double mid)
{double dis[maxn];int vis[maxn];int i,j;for(i=0;i<=n;i++){dis[i]=INF;vis[i]=0;}for(i=1;i<=n;i++){for(j=1;j<=n;j++){maps[i][j].s=maps[i][j].h-maps[i][j].l*mid;}}dis[1]=0;double ans;ans=0;while(1){double minn=INF;int ip;for(i=1;i<=n;i++){if(vis[i])continue;if(dis[i]<minn){minn=dis[i];ip=i;}}if(zero(minn-INF)==0)break;vis[ip]=1;ans+=minn;for(i=1;i<=n;i++){if(vis[i])continue;dis[i]=min(dis[i],maps[ip][i].s);}}return ans;
}
int main()
{int i,j;while(~scanf("%d",&n)&&n){m=0;for(i=1;i<=n;i++)scanf("%d%d%d",&p[i].x,&p[i].y,&p[i].h);for(i=1;i<=n;i++){for(j=1;j<=n;j++){maps[i][j].h=fabs(p[i].h-p[j].h);maps[i][j].l=dist(i,j);}}double l,r,mid;l=0;r=100;mid=(l+r)/2;while(zero(r-l)>0){mid=(l+r)/2;if(prime(mid)>0)l=mid;else r=mid;}printf("%.3f\n",mid);}return 0;
}