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:\n",Icase);

        cout<<"The minimal distance is: ";

        printf("%.2lf",sum);

        cout<<endl;

    }

    return 0;

}