(BFS)
#include<bits/stdc++.h>
using namespace std;
int nodecount, edgecount;
bool vis[1005];

void bfs(int src,vector <int>g[1005])
{
    queue <int>q;
    q.push(src);
    vis [src]=true;
    while (!q. empty())
    {
        int u = q. front();
        cout << u << endl;
        q.pop();
        for (auto v: g[u])
        {
            if(!vis[v])
            {
                vis[v]=true;
                q.push(v);
            }
        }
    }
}
int main()
{
    cin>>nodecount>>edgecount;
    memset(vis,false,sizeof(vis));
    vector<int>g[1005];
    for (int i=1; i<=edgecount;i++)
    {
        int a,b;
        cin>>a>>b;
        g[a].push_back(b);
    }
    bfs(2,g);
}
(prims algo)
#include<bits/stdc++.h>
using namespace std;

typedef pair<int,int>pill;
int nodecount, edgecount;
bool vis[1005];

int primsmst(int source, vector<vector<int>>g[1005])
{
    priority_queue<pill,vector<pill>,greater<pill>>pq;
    int res=0;
    pq.push({0,0});
    while(!pq.empty())
    {
        auto p = pq.top();
        pq.pop();
        int weight = p.first;
        int u=p.second;

        if(vis[u]==true)
        {
            continue;
        }
        res +=weight;
        vis[u]=true;
        for(auto v: g[u])
        {
            pq.push({v[1],v[0]});
        }
    }
}
int main()
{
    cin>>nodecount>>edgecount;
    memset(vis,false,sizeof(vis));
    vector<vector<int>>g[1005];
    for (int i=1; i<=edgecount;i++)
    {
        int a,b,weight;
        cin>>a>>b>>weight;
        g[a].push_back({b,weight});
        g[b].push_back({a,weight});
    }
    int res=primsmst(0,g);
    cout<<res<<endl;
}