Overtree

#include <bits/stdc++.h>

using namespace std;
int parent[100010];

using tu = tuple<int ,int ,int>;
int find(int u){
    if(parent[u]==u){
        return u;
    }
    return parent[u]=find(parent[u]);
}

void merge(int u ,int v){
     u=find(u);
     v=find(v);

    if(u==v){
        return ;
    }
    if(u>v){
        parent[v]=u;
    }
    else{
        parent[u]=v;
    }
}
int main(){
    int n,m;

    scanf("%d%d",&n,&m);
    for(int i=1;i<=n;++i){
        parent[i]=i;
    }
    int u , v ,w;
    vector<tu> way;
    for(int i=0;i<m;++i){
        scanf("%d%d%d",&u,&v,&w);
        way.push_back(make_tuple(w,u,v));
    }
    sort(way.begin(),way.end());
    for(auto c : way){
        if(find(get<1>(c))==find(get<2>(c))){
            continue;
        }
        cout << get<1>(c) << " " << get<2>(c) << "\n";

        merge(get<1>(c),get<2>(c));
    }


    return 0;

}