zoj1203最小生成树

#include<stdio.h>
#include<iostream>
#include<string.h>
#include<queue>
#include<stack>
#include<list>
#include<stdlib.h>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<math.h>
using namespace std;

int father[10000];
int getfather(int x)
{
    if(x!=father[x])
        father[x]=getfather(father[x]);
    return father[x];
}


struct Node
{
    int a;int b;double dist;
}node[111111];

double dist(double x,double y,double x1,double y1)
{
    return sqrt((x-x1)*(x-x1)+(y-y1)*(y-y1));
}
bool cmp(const Node & a,const Node &b)
{
    if(a.dist<b.dist) return true;
    return false;
}
int main()
{
    int n;
    double x[1000],y[1000];
    int Icase=0;
    while(cin>>n,++Icase&&n){
        for(int i=1;i<=n;i++)
            father[i]=i;
        for(int i=1;i<=n;i++){
            cin>>x[i]>>y[i];
        }
        int ans=0;
        for(int i=1;i<=n;i++)
        for(int j=i+1;j<=n;j++){
            double dis=dist(x[i],y[i],x[j],y[j]);
          //  cout<<x[i]<<" "<<y[i]<< " "<<x[j]<< " "<<y[j]<<" "<<dis<<endl;system("pause");
            node[ans].a=i;node[ans].b=j;node[ans++].dist=dis;
        }
        sort(node,node+ans,cmp);
      //  for(int i=0;i<ans;i++)
         //   cout<<node[i].a<<" "<<node[i].b<<" "<<node[i].dist<<endl;
        double sum=0;
        for(int i=0;i<ans;i++){
            int a=node[i].a;int b=node[i].b;
            int fa=getfather(a);int fb=getfather(b);
            if(fa!=fb){
                father[fa]=fb; sum+=node[i].dist;
            }
        }
        if(Icase>1) cout<<endl;
        printf("Case #%d:
",Icase);
        cout<<"The minimal distance is: ";
        printf("%.2lf",sum);
        cout<<endl;
    }
    return 0;
}