HDU 1875

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
using namespace std;
int n,t,m,k;
int p[105];
struct Edge
{
int u;
int v;
double w;
}edge[5010];
struct Island
{
double x;
double y;
}island[105];
bool cmp(Edge a ,Edge b)
{
return a.w<b.w;
}
int find(int x)
{
return p[x]==x?x:x=find(p[x]);
}
double kruskal()
{
for(int i=0;i<n;i++)
{
p[i]=i;
}
sort(edge,edge+k,cmp);
int num=0;
double ans=0;
for(int i=0;i<k;i++)
{
int p1=find(edge[i].u);
int p2=find(edge[i].v);
if(p1!=p2)
{
ans+=edge[i].w;
num++;
p[p1]=find(p2);
}
if(num==n-1)
return ans;
}

return -1;

}
int main()
{
scanf("%d",&t);
while(t--)
{
scanf("%d",&n);
k=0;
for(int i=0;i<n;i++)
{
scanf("%lf%lf",&island[i].x,&island[i].y);
}
for(int i=0;i<n;i++)
for(int j=i+1;j<n;j++)
{
double p=sqrt((island[i].x-island[j].x)*(island[i].x-island[j].x)
+(island[i].y-island[j].y)*(island[i].y-island[j].y));
if(p>=10&&p<=1000)
{
edge[k].u=i;
edge[k].v=j;
edge[k].w=p;
k++;
}
}

double ans=kruskal();
if(ans==-1)
printf("oh!\n");
else
{
printf("%.1lf\n",ans*100);
}
}

return 0;
}