HDU 1875 畅通工程再续(kruskal)

2
2
10 10
20 20
3
1 1
2 2
1000 1000
#include <iostream>
#include <string.h>
#include <math.h>
#include <algorithm>
#include <stdlib.h>
#include <stdio.h>

using namespace std;
struct Node
{
	int x;
	int y;
	double w;
}a[100*100+5];
int father[105];
int n;
int find(int x)
{
	if(x!=father[x])
		father[x]=find(father[x]);
	return father[x];
}
int b[105];
int c[105];
int cmp(Node a,Node b)
{
	return a.w<b.w;
}
double judge(int x,int y)
{
	double len=sqrt(1.0*(b[x]-b[y])*(b[x]-b[y])+1.0*(c[x]-c[y])*(c[x]-c[y]));
	if(len>=10&&len<=1000)
		return len;
	return 0;
}
int main()
{
	int t;
	scanf("%d",&t);
	while(t--)
	{
		scanf("%d",&n);
		for(int i=1;i<=n;i++)
		{
			scanf("%d%d",&b[i],&c[i]);
		}
		int cot=0;
		for(int i=1;i<=n;i++)
		{
            for(int j=i+1;j<=n;j++)
			{
				  double len=judge(i,j);
                  if(judge(i,j))
				  {
					  a[cot].x=i;
					  a[cot].y=j;
					  a[cot++].w=len*100;
				  }
			}
		}
		sort(a,a+cot,cmp);
		for(int i=1;i<=n;i++)
			father[i]=i;
		double ans=0;
		for(int i=0;i<cot;i++)
		{
              int xx=find(a[i].x);
			  int yy=find(a[i].y);
			  if(xx!=yy)
			  {
				  ans+=a[i].w;
				  father[xx]=yy;
			  }
		}
		int tag=0;
		for(int i=1;i<=n;i++)
		{
             find(i);
			 if(father[i]==i)
				 tag++;
		}
		if(tag>=2)
			printf("oh!\n");
		else
			printf("%.1f\n",ans);
	}
	return 0;

}