Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < N; i++ {
		u, k := sc.nextInt()-1, sc.nextInt()
		for j := 0; j < k; j++ {
			G[u] = append(G[u], sc.nextInt()-1)
		}
	}
	ans := make([][2]int, N)
	time := 0
	found := make(map[int]bool)
	var dfs func(cur int)
	dfs = func(cur int) {
		time++
		ans[cur][0] = time
		found[cur] = true
		for i := 0; i < len(G[cur]); i++ {
			next := G[cur][i]
			if !found[next] {
				dfs(G[cur][i])
			}
		}
		time++
		ans[cur][1] = time
	}
	for i := 0; i < N; i++ {
		if !found[i] {
			dfs(i)
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprint(wtr, i+1)
		for j := 0; j < 2; j++ {
			fmt.Fprint(wtr, " ")
			fmt.Fprint(wtr, ans[i][j])
		}
		fmt.Fprintln(wtr)
	}
	wtr.Flush()
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

struct status{
    int idx_node;
    vector<int> children;
    int finded = 0;
    int visited = 0;
};

int step = 0;
vector<status> graph;

void dfs(int now_node){
    ++step;
    graph[now_node-1].finded = step;
    for(auto&& next_node:graph[now_node-1].children){
        if(not graph[next_node-1].finded){
            dfs(next_node);
        }
    }
    ++step;
    graph[now_node-1].visited = step;
}

int main(void){cin.tie(0);ios::sync_with_stdio(false);

    //stdi
    int nb_nodes; cin >> nb_nodes;
    graph.resize(nb_nodes);
    for(auto& times:graph){
        int idx_node; cin >> idx_node; graph[idx_node-1].idx_node = idx_node;
        int nb_edges; cin >> nb_edges; graph[idx_node-1].children.resize(nb_edges);
        for(auto& a:graph[idx_node-1].children){
            cin >> a;
        }
        sort(graph[idx_node-1].children.begin(),graph[idx_node-1].children.end());
    }
    
    //dfs
    int root = 1;
    dfs(root);
    
    //stdo
    for(auto& a:graph){
        cout<<a.idx_node<<" "
            <<a.finded<<" "
            <<a.visited<<"\n";
    }
}

C++: #include <iostream>
#include <vector>
using namespace std;

int n;
vector<vector<int> > A;
vector<vector<int> > T;
int timer = 0;

void dfs(int cur){
    timer += 1;
    T[cur][0] = timer;

    for(int dst = 0; dst < n; ++dst){
        if(A[cur][dst] == 1 && T[dst][0] == -1){
            dfs(dst);
        }
    }
    timer += 1;
    T[cur][1] = timer;
}

int main(){
    cin >> n;
    A = vector<vector<int> >(n, vector<int>(n, 0));
    T = vector<vector<int> >(n, vector<int>(2, -1));
    for(int i=0; i<n; ++i){
        int k;
        cin >> k;
        k -= 1;
        int u;
        cin >> u;
        for(int j=0; j<u; ++j){
            int v;
            cin >> v;
            v -= 1;
            A[k][v] = 1;
        }
    }
    for(int i=0; i<n; ++i){
        if(T[i][0] == -1){
          dfs(i);
        }
    }
    for(int i=0; i<n; ++i){
        cout << i+1 << " " << T[i][0] << " " << T[i][1] << endl;
    }
}

C++: #include <stdio.h>
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

int n, M[N][N];
int color[N], d[N], f[N], tt;

void dfs_visit(int u) {
    int v;
    color[u] = GRAY;
    d[u] = ++tt;
    for ( v = 0; v < n; v++){
        if ( M[u][v] == 0) {
            continue;
        }
        if (color[v] == WHITE) {
            dfs_visit(v);
        }
    }
    color[u] = BLACK;
    f[u] = ++tt;
}

void dfs(){
    int u;
    for ( u = 0; u < n; u++) {
        color[u] = WHITE;
    }
    tt = 0;
    for (u = 0; u < n; u++) {
        if ( color[u] == WHITE ) {
            dfs_visit(u);
        }
    }

    for (u = 0; u < n; u++) {
        printf("%d %d %d\n", u + 1, d[u], f[u]);
    }
}

int main() {
    int u, v, k, i, j;
    scanf("%d", &n);
    for (i = 0; i < n; i++) {
        for (j = 0; j < n; j++){
            M[i][j] = 0;
        }
    }

    for (i = 0; i < n; i++) {
        scanf("%d %d", &u, &k);
        u--;
        for (j = 0; j < k; j++){
            scanf("%d", &v);
            v--;
            M[u][v] = 1;
        }
    }

    dfs();
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, start, n) for (int i = (int)(start); i < (int)(n); ++i)
void func(vector<vector<int> > &G, int *d, int *c)
{
    int time(0);
    stack<int> s;
    int count = 0;
    bool check;
    rep(p, 1, G.size())
    {
        if (d[p] == 0)
        {
            do
            {
                // cout << p << endl;
                check = true;
                if (d[p] == 0)
                {
                    s.push(p);
                    d[p] = ++count;
                }
                rep(i, 0, G[p].size())
                {
                    if (d[G[p][i]] == 0)
                    {
                        check = false;
                        p = G[p][i];
                        break;
                    }
                }
                if (check)
                {
                    c[p] = ++count;
                    s.pop();
                    if (s.size())
                        p = s.top();
                    else
                    {
                        p = 0;
                    }
                }
            } while (s.size());
        }
    }
}
int main()
{
    int n;
    cin >> n;
    int u, k, v;
    vector<vector<int> > G(n + 1, vector<int>(0));   //グラフ
    int discover[n + 1] = {}, complete[n + 1] = {}; //発見時刻と完了時刻
    rep(i, 0, n)
    {
        cin >> u >> k;
        rep(j, 0, k)
        {
            cin >> v;
            G[u].push_back(v);
        }
    }
    func(G, discover, complete);
    rep(i, 1, n + 1)
    {
        printf("%d %d %d\n", i, discover[i], complete[i]);
    }
}