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<cstdio>
#include<iostream>
#include<string>
using namespace std;

int n,m[101][101];
int d[101],f[101],t=0,vis[101];

void dfs(int u){
    if(vis[u]) return;
    vis[u] = 1;
    d[u] = ++t;
    for( int i = 1; i <= n; i++ ){
        if( vis[i]==0 && m[u][i] ){
            dfs(i);
        }
    }
    f[u] = ++t;
}

int main(){
    int i,j,k,u,v,du;
    scanf("%d",&n);
    k = n;
    while(k--){
        scanf("%d",&u);
        scanf("%d",&du);
        while(du--){
            scanf("%d",&v);
            m[u][v]  = 1;
        }
    }
    for( i = 1; i <= n; i++ ){
        dfs(i);
        cout << i << " " << d[i] << " " << f[i] << endl;
    }
}

C++: #define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <cstdio>
#include <stack>
using namespace std;
stack<int> st;
int  v[102][101], n;
int  tim[102][2];
int ct = 1;
int go[102];
inline void search(int t) {
	if(!tim[t][0]) tim[t][0] = ct++;
	go[t] = 1;
	int tf = 0;
	for (int a = 1; a <= n; a++) {
		if (v[t][a]) {
			st.push(a);
			for (int i = 1; i <= n; i++) {
				v[i][a] = 0;
			}
			search(st.top());
			tf = 1;
		}
	}
		
	if(!tf) {
		st.pop();
		tim[t][1] = ct++;
		if(!st.empty()) search(st.top());
	}
}
int main() {

	st.push(1);
	int u, k, s;
	cin >> n;
	for (int i = 0; i <= n; i++) {
		for (int j = 0; j <= n; j++) {
			v[i][j] = 0;
		}
	}
	for (int i = 0; i < n; i++) {
		cin >> u;
		cin >> k;
		for (int j = 0; j < k; j++) {
			cin >> s;
			v[u][s] = 1;
		}
	}
	search(1);
	for (int i = 2; i <= n; i++) {
		if (!go[i]) search(i);
	}
	for (int i = 1; i <= n; i++) {
		cout << i << " " << tim[i][0] << " " << tim[i][1] << endl;
	}
	return 0;
}

C++: #include <stdio.h>
#include <iostream>
using namespace std;

class Adjl{
private:
	int u;
	int k;
	Adjl **next;
protected:
	int d;
	int f;
public:
	Adjl(int u);
	~Adjl(){ if (next != NULL) delete[] next; }
	void setV(int k, Adjl *vk);
	int depthFirstSearch(int time);
	void print();
};

Adjl::Adjl(int u)
{
	this->u = u;
	k = 0;
	next = NULL;
	d = 0;
	f = 0;
}

void Adjl::setV(int k, Adjl *vk)
{
	if (this->k == 0) next = new Adjl*[k];
	next[this->k] = vk;
	(this->k)++;
}

int Adjl::depthFirstSearch(int time)
{
	if (d != 0) return time;
	time++;
	d = time;
	for (int i = 0; i < k; i++) {
		time = next[i]->depthFirstSearch(time);
	}
	time++;
	f = time;
	return time;
}

void Adjl::print()
{
	cout << u << " " << d << " " << f << endl;
}

int main(void)
{
	int n;
	cin >> n;
	
	Adjl **adjl = new Adjl*[n];
	int check[100] = {0};

	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		if (check[i] == 0) {
			adjl[i] = new Adjl(u);
			check[i] = 1;
		}
		check[i] = 1;
		for (int j = 0; j < k; j++) {
			int vk;
			cin >> vk;
			if (check[vk - 1] == 0) {
				adjl[vk - 1] = new Adjl(vk);
				check[vk - 1] = 1;
			}
			adjl[i]->setV(k, adjl[vk - 1]);
		}
	}

	int time = 0;
	for (int i = 0; i < n; i++) {
		time = adjl[i]->depthFirstSearch(time);
	}

	for (int i = 0; i < n; i++) {
		adjl[i]->print();
	}

	delete[] adjl;
	return 0;
}

C++: #include <iostream>
#include <string>
#include <unordered_map>
#include <stdio.h>
#include <list>
#include <vector>
#include <algorithm>
#include <stack>
#include <queue>
using namespace std;
#define rep(i, n) for(int i = 0; i < n; ++i)
typedef long long ll;

vector<vector <int>> v;
int color[100],d[100],f[100],t,n;

void dfs_visit(int u)
{
	color[u]=1;
	d[u]=++t;
	int next=-1;
	rep(i,v[u].size())
	{
		if(color[v[u][i]]==0)
		{
			next=v[u][i];
			dfs_visit(next);
		}
	}
	f[u]=++t;
}

void dfs()
{
	rep(i,n)color[i]=0;
	t=0;

	rep(i,n)
	{
		if(color[i]==0)dfs_visit(i);
	}
}

int main()
{
	cin >> n;
	rep(i,n)
	{
		int hoge;cin >> hoge;
		int k;cin >> k;
		v.push_back(vector <int>());
		rep(j,k)
		{
			int fooo; cin >> fooo;
			v[i].push_back(fooo-1);
		}
	}

	dfs();
	rep(i,n)
	{
		cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
	}
	return 0;
}

C++: #include <iostream>
#include <stack>

using namespace std;

#define MAX 110
int num;
int matrix[MAX][MAX];
int dst[MAX];

void input(){
    cin >> num;
    for(int i=0;i<MAX;i++){
        dst[i] = -1;
        for(int j=0;j<MAX;j++){
            matrix[i][j] = 0;
        }
    }
    for(int i=1;i<=num;i++){
        int v; cin >> v;
        int tmp; cin >>tmp;
        for(int j=0;j<tmp;j++){
            int vi; cin >> vi;
            matrix[v-1][vi-1] = 1;
        }
    }
}

void dfs(){
    stack<int> S;
    S.push(0);
    dst[0] = 0;
    while(!S.empty()){
        int cur = S.top();
        S.pop();
        if(dst[cur]==-1 || dst[cur]== 0){
            for(int i=0;i<num;i++){
                if(matrix[cur][i]==1){
                    S.push(i);
                    dst[i] = dst[cur] + 1;
                }
            }
        }
        else if(dst[S.top()]+1 < dst[cur]){
            for(int i=0;i<num;i++){
                if(matrix[cur][i]==1){
                    if(dst[cur] +1 <= dst[i]){
                        S.push(i);
                        dst[i] = dst[cur] + 1;
                    }
                }
            }
        }
    }
    for(int i=0;i<num;i++){
        cout << i+1 << " " <<  dst[i] << endl;
    }
}

int main(){
    input();
    dfs();
}