PRIM

#include<iostream>
#include<cstdlib>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
using namespace std;
const int maxn=99999999;
int n,m,cnt=1,ans,e[1005][1005],dis[1005],book[1005]; 
int main()
{
    int i,j,a,b,c;
    scanf("%d%d",&n,&m);
    for(i=1;i<=n;i++)
    {
        for(j=1;j<=n;j++)
        {
            if(i==j) e[i][j];
            else e[i][j]=maxn;
        }
    }
    book[1]=1;
    for(i=1;i<=m;i++)
    {
        scanf("%d%d%d",&a,&b,&c);
        e[a][b]=c;
        e[b][a]=c;
    }
    for(i=1;i<=n;i++) dis[i]=e[1][i];
    while(cnt<n)
    {
        int minn=maxn,u;
        for(j=1;j<=n;j++)
        {
            if(dis[j]<minn && book[j]==0)
            {
                minn=dis[j];
                u=j;
            }
        }
        book[u]=1;
        cnt++;
        ans+=dis[u];
        for(j=1;j<=n;j++)
        {
            if(e[u][j]<maxn)
            {
                if(dis[j]>e[u][j])
                    dis[j]=e[u][j];
            }
                
        }
    }
    //for(i=1;i<=n;i++) ans+=dis[i];
    printf("%d",ans);
    return 0;
}
/*
6 9
2 4 11
3 5 13
4 6 3
5 6 4
2 3 6
4 5 7
1 2 1
3 4 9
1 3 2
*/