Go: package main

import "fmt"

type node struct {
	id, d, v int
	adj      []node
}

var n int
var seen []bool
var graph []node

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func dfs(v, t int) int {
	// fmt.Printf("dfs(v %d, t %d) en:\n", v, t)
	seen[v] = true
	graph[v].v = t
	tt := t
	for _, vv := range graph[v].adj {
		if !seen[vv.id] {
			tt = max(tt, dfs(vv.id, tt+1))
		}
	}
	graph[v].d = tt + 1
	// fmt.Printf("dfs(v %d, t %d) ex: d %d\n", v, t, graph[v].d)
	return graph[v].d
}

func main() {
	fmt.Scan(&n)
	graph = make([]node, n+1)
	for i := 1; i <= n; i++ {
		var u, k, v int
		fmt.Scan(&u, &k)
		graph[u].id = u
		// 頂点uはk個の隣接頂点を持っている
		for j := 0; j < k; j++ {
			fmt.Scan(&v)
			var t node
			t.id = v
			graph[u].adj = append(graph[u].adj, t)
		}
	}
	// fmt.Println("n", n, "graph", graph)
	seen = make([]bool, n+1)
	// t := dfs(1, 1)
	v, t := 1, 1
	done := false
	for !done {
		tt := dfs(v, t)
		done = true
		for i := range seen {
			if !seen[i] {
				done = false
				v = graph[i].id
				t = tt
				break
			}
		}
	}
	for i := 1; i <= n; i++ {
		fmt.Printf("%d %d %d\n", i, graph[i].v, graph[i].d)
	}
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cassert>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define rep(i,n) FOR(i,0,n)
#define DEBUG(x) cout<<#x<<": "<<x<<endl
#define vint vector<int>
#define vdouble vector<double>
#define vstring vector<string>
using namespace std;

#include<map>
#include<set>
#include<queue>

typedef long long ll;
typedef unsigned long long ull;

const int MAX_N = 1000000;
static const int INFTY = (1 << 21);

class Edge{
public:
    int from, to, cost;
    Edge(int from = 0, int to = 0, int cost = 0) :
            from(from), to(to), cost(cost){}

    bool operator < (const Edge &e) const{
        return cost < e.cost;
    }
    bool operator >(const Edge &e) const{
        return cost > e.cost;
    }

};

class Node{
public:
    vector<Edge> edges;
    int dist;
    int done;
    int times;
    int timee;

    Node(){
        dist = INFTY;
        done = 0;
    }
};

class Graph{
public:
    vector<Node> nodes;
    Graph(int n) {
        rep(i, n) { Node n;  nodes.push_back(n); }
    }
    Node& operator[](int i){
        return nodes[i];
    }
};

class Data{

public:
    int dist;
    Edge *edge;
    Data(int dist, Edge *edge) {
        this->dist = dist;
        this->edge = edge;
    }

    bool operator < (const Data &d) const{
        return dist < d.dist;
    }
    bool operator >(const Data &d) const{
        return dist > d.dist;
    }
};

Graph G(0);

int V;
int t;

void dfs(int v){
    if (G[v].done != 0) return;

    // fprintf(stderr, "%d %d\n", v, t);

    G[v].done = 1;
    t++;
    G[v].times = t;
    for(auto &e: G[v].edges){
        dfs(e.to);
    }
    t++;
    G[v].timee = t;
}

void dfs_run(){
    t = 0;
    dfs(0);
}

int main() {

    int V;
    cin >> V;
    G = Graph(V);

    rep(i, V){
        int from; cin >> from; from--;
        int e_count; cin >> e_count;

        vint vec;
        rep(j, e_count){
            int to; cin >> to; to--;
            vec.push_back(to);
        }
        sort(vec.begin(), vec.end());
        rep(j, e_count){
            G[from].edges.push_back(Edge(from, vec[j], 1));
        }
    }

    dfs_run();

    rep(i, V){
        fprintf(stdout, "%d %d %d\n", i+1, G[i].times, G[i].timee);
    }
}

C++: #include <iostream>
#include <fstream>
#include <stdio.h>
#include <math.h>
#include <algorithm>

using namespace std;

int n;
int arr[100][100];
int time_saver[100][2];
int now_time;

void search(int fi){
    if(!time_saver[fi][0]){
        now_time++;
        time_saver[fi][0] = now_time;
    }
    for(int i=0; i<100; i++){
        if(arr[fi][i] && !time_saver[arr[fi][i]-1][0])search(arr[fi][i]-1);
    }
    if(!time_saver[fi][1]){
        now_time++;
        time_saver[fi][1] = now_time;
    }
}

int main(int argc, const char * argv[]) {
    
    
    /////////
    //write//
    /////////
    
    cin >> n;
    now_time = 0;
    for(int i=0; i<100; i++){
        for(int j=0; j<100; j++){
            arr[i][j] = 0;
        }
        for(int j=0; j<2; j++){
            time_saver[i][j] = 0;
        }
    }
    
    for(int i=0; i<n; i++){
        int node, degree; cin >> node >> degree;
        for(int j=0; j<degree; j++){
            int tmp; cin >> tmp;
            arr[node-1][tmp-1] = tmp;
        }
    }
    
    for(int i=0; i<n; i++){
        if(time_saver[i][0])continue;
        search(i);
    }
    
    for(int i=0; i<n; i++){
        for(int j=0; j<2; j++){
            if(j)cout << " ";
            else cout << i+1 << " ";
            cout << time_saver[i][j];
        }
        cout << endl;
    }
    
    return 0;
}

C++: #include "bits/stdc++.h"

using namespace std;

using ll = long long;

template<typename T> using V = std::vector<T>;
using Vi = V<int>;
using VVi = V<V<int>>;
using Vl = V<ll>;
using VVl = V<V<ll>>;
using Vs = V<string>;

template<typename T1, typename T2> using P = std::pair<T1, T2>;
using Pii = P<int, int>;
using Pll = P<ll, ll>;
using Pdd = P<double, double>;

template<typename T1, typename T2> using M = std::map<T1, T2>;
using Mii = M<int, int>;
using Msi = M<string, int>;

#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define REP2(i,s,e) for(int i=(int)(s);i<(int)(e);++i)
#define RREP(i,s,e) for(int i=(int)(s);i>=(int)(e);--i)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin(),ie=(c).end();i!=ie;++i)
#define ALL(c) (c).begin(), (c).end()

const double PI = acos(-1);
const ll MOD = 1e9+7;

int n;
string s;

int main() {
    cin >> n;

    VVi edges(n);
    REP(i, n) {
        int u, k;
        cin >> u >> k;
        u--;
        REP(j, k) {
            int v; cin >> v;
            v--;
            edges[u].push_back(v);
        }
    }

    Vi find(n, -1), end(n, -1);
    stack<int> s;
    s.push(0);
    int time = 1;
    while (true) {
        while (!s.empty()) {
            int node = s.top();
            if (find[node] == -1) {
                find[node] = time;
                time++;
            } else {
                if (end[node] == -1) {
                    end[node] = time;
                    time++;
                }
                s.pop();
                continue;
            }
            RREP(i, edges[node].size()-1, 0) {
                int v = edges[node][i];
                if (find[v] == -1) {
                    s.push(v);
                }
            }
        }
        int idx = -1;
        REP(i, n) if (find[i] == -1) {
            idx = i;
            break;
        }
        if (idx == -1) {
            break;
        }
        s.push(idx);
    }

    REP(i, n) {
        printf("%d %d %d\n", i+1, find[i], end[i]);
    }

    return 0;
}