Kruskal

/*
    Task    : Kruskal
    Author  : Phumipat C. [MAGCARI]
    Language: C++
    Created : 30 July 2022 [09:03]
*/
#include<bits/stdc++.h>
using namespace std;
struct A{
    int u,v,w;
    bool operator < (const A&o) const{
        if(w!=o.w)  return w<o.w;
        else        return v<o.v;
    }
};
int p[100010];
int fr(int u){
    if(u == p[u])   return u;
    else            return p[u] = fr(p[u]);
}
vector<A > edges;
int main(){
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);

    int n,m,u,v,w;
    cin >> n >> m;

    for(int i=1;i<=n;i++)
        p[i] = i;

    for(int i=1;i<=m;i++){
        cin >> u >> v >> w;
        edges.push_back({u,v,w});
    }

    sort(edges.begin(),edges.end());

    int sum = 0;
    for(auto x:edges){
        int ru = fr(x.u),rv = fr(x.v);
        if(ru == rv)    continue;
        sum+=x.w;
        p[ru] = rv;
    }

    cout << sum << '\n';
    return 0;
}