BOJ 2887 행성 터널

void solve(){
    int N; cin >> N;
    vector<array<ll, 4>> planets;
    rep(i, 0, N){
        int x, y, z; cin >> x >> y >> z;
        planets.push_back({x, y, z, i});
    }
    vector<array<ll, 3>> edges;
    sort(all(planets), [](auto &a, auto &b){
        return a[0] < b[0];
    });
    rep(i, 0, N-1) edges.push_back({abs(planets[i][0]-planets[i+1][0]), planets[i][3], planets[i+1][3]});
    sort(all(planets), [](auto &a, auto &b){
        return a[1] < b[1];
    });
    rep(i, 0, N-1) edges.push_back({abs(planets[i][1]-planets[i+1][1]), planets[i][3], planets[i+1][3]});
    sort(all(planets), [](auto &a, auto &b){
        return a[2] < b[2];
    });
    rep(i, 0, N-1) edges.push_back({abs(planets[i][2]-planets[i+1][2]), planets[i][3], planets[i+1][3]});
    sort(all(edges));
    UF.init(N);
    ll ans = 0;
    for(auto [w, u, v]: edges) if(UF.merge(u, v)) ans += w;
    cout << ans << '\n';
}