【板子】最小生成树

1.Kruskal

#include <iostream>
#include <cmath>
#include <cstdio>
#include <string.h>
#include <stdio.h>
#include <algorithm>
using namespace std;
int n;
struct edge
{
    int from,to,weight;
}e[100];
int par[30];
bool cmp(edge a,edge b)
{
    return a.weight<b.weight;
}
int find(int x)
{
    return par[x]==x?x:par[x]=find(par[x]);
}
int main()
{
    while(cin>>n&&n)
    {
        for(int i=0;i<n;i++)
        {
            par[i]=i;
        }
        int cnt=0,ans=0;
        for(int i=1;i<n;i++)
        {
            int weight,num;
            char start,end;
            cin>>start>>num;
            for(int j=0;j<num;j++,cnt++)
            {
                cin>>end>>weight;
                e[cnt].from=start-'A';
                e[cnt].to=end-'A';
                e[cnt].weight=weight;
            }
        }
        sort(e,e+cnt,cmp);
        for(int i=0;i<cnt;i++)
        {
            int x=find(e[i].from);
            int y=find(e[i].to);
            if(x!=y)
            {
                ans+=e[i].weight;
                par[y]=x;
            }
        }
        cout<<ans<<endl;
    }
    system("pause");
    return 0;
}

2.Prim

#include <bits/stdc++.h>
using namespace std;
const double inf=9999999;
int n;
double x[100],y[100];
double edge[100][100];
double temp;
int vis[100];
double dis[100];
int nike,apple;
void prim()
{
    int v;
    memset(vis,0,sizeof(vis));
    for(int i=1;i<=n;i++)
    {
        dis[i]=edge[1][i];
    }
    double sum=temp;
    double mi;
    vis[1]=1;
    for(int i=1;i<n;i++)
    {
        mi=inf;
        for(int j=1;j<=n;j++)
        {
            if(!vis[j]&&mi>dis[j])
            {
                v=j;
                mi=dis[j];
            }
        }
        vis[v]=1;
        sum+=dis[v];
        for(int j=1;j<=n;j++)
        {
            if(!vis[j]&&dis[j]>edge[v][j])
            {
                dis[j]=edge[v][j];
            }
        }
    }
    printf("%.2lf\n",sum);
}
int main()
{
    while(cin>>n&&n)
    {
        for(int i=1;i<=n;i++)
        {
            for(int j=1;j<=n;j++)
                edge[i][j]=inf;
            edge[i][i]=0;
        }
        scanf("%d%d",&nike,&apple);
        for(int i=1;i<=n;i++)
        {
            scanf("%lf%lf",&x[i],&y[i]);
        }
        for(int i=1;i<=n;i++)
        {
            for(int j=i+1;j<=n;j++)
            {
                edge[i][j]=edge[j][i]=sqrt((x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]));
            }
        }
        temp=edge[nike][apple];
        edge[nike][apple]=edge[apple][nike]=0;
        prim();
    }
    //system("pause");
    return 0;
}