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 <algorithm>
#include <iostream>
using namespace std;

int t=0,k,n;
int gone[100+10]={},a[100+10][100+10]={},d[200+10],f[200+10];

void dfs(int cur){
    if(gone[cur]!=1){
        t+=1;
        d[cur]=t;
        gone[cur]=1;
    }
    for(int m=1;m<=n;m++){
        if(a[cur][m]==1){
            if(gone[m]==0){
                dfs(m);
            }
        }
    }
    t+=1;
    f[cur]=t;
}

int main(){
    cin >> n;
    for(int i=1;i<=n;i++){
        int u,p;
        cin >> u >> k;
        for(int j=0;j<k;j++){
            cin >> p;
            a[i][p]=1;
        }
    }
    for(int q=1;q<=n;q++){
        if(gone[q]!=1) dfs(q);
    }
    for(int r=1;r<=n;r++){
        cout << r << " " << d[r] << " " << f[r] << endl;
    }
}

C++: #include<bits/stdc++.h>
using namespace std;
int a[105][105];
pair<int,int> ans[105];
int co;
int n;
void dfs(int x){
  if(ans[x].first==0){
    co++;
    ans[x].first = co ;
  }
  //cout << n << endl;
  for(int i=0;i<n;i++){
    //cout << a[x][i]<<endl;
    if(a[x][i]==1)dfs(i);
  }
  if(ans[x].second==0){
    co++;
    ans[x].second=co;
  }
}

int main(){
  cin >> n;
  for(int i=0;i<n;i++){
    int u,m;
    cin >> u >> m;
    for(int j=0;j<m;j++){
      int v;
      cin >> v;
      a[u-1][v-1]=1;
    }
  }
  dfs(0);
  for(int i=0;i<n;i++){
    cout << i+1 << " " << ans[i].first << " "<< ans[i].second << endl;
  }
  return 0;
}

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

#define Max 100
#define white 0
#define gray 1
#define black 2
using namespace std;
int dia=0;
int d[Max+1],f[Max+1];
	bool g[Max+1][Max+1];
	int color[Max+1];
	
void dft(int a,int n){
	int i;
	color[a]=gray;
	d[a]=++dia;
	for(i=1;i<=n;i++){
		if(g[a][i] && color[i]==white)
			dft(i,n);	
		}
		color[a]=black;
		f[a]=++dia;
	
}
void defa( int n){
	int i;
	for( i=1;i<=n;i++)
	color[i]=white;
	for(i=1;i<=n;i++){
		if(color[i]==white)
		dft(i,n);
	}
}
main(){
	int j,i,n,u,k,v;
	
	scanf("%d",&n);
	for(i=1;i<=n;i++){
		for(j=1;j<=n;j++)
		g[i][j]=false;
	}
	for(i=1;i<=n;i++){
		scanf("%d%d",&u,&k);
		for(j=0;j<k;j++){
		scanf("%d",&v);
		g[u][v]=true;
		}
	}
	defa(n);
	for(i=1;i<=n;i++)
	printf("%d %d %d\n",i,d[i],f[i]);
	
	return 0;
}

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

int r[101][101];
int d[101], f[101], num, visit[100]={0}, p=0;

void dfs(int n){
    if(!visit[n]){
        visit[n]++;
        d[n] = ++p;
        for(int i=1; i<num+1; i++)
            if(r[n][i]) dfs(i);
        f[n] = ++p;
    }
}

int main(void){
    int u, k, v;
    cin >> num;
    for(int i=0; i<num; i++){
        cin >> u >> k;
        for(int j=0; j<k; j++){
            cin >> v;
            r[u][v]++;
        }
    }
    for(int i=1; i<num+1; i++){
        if(!visit[i]) dfs(i);
    }
    for(int i=1; i<num+1; i++)
        cout << i << " " << d[i] << " " << f[i] << endl;
}

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

void InputSet(std::vector<int> & a) {
	int n;
	cin >> n;
	a.resize(n,0);
	for(int i=0;i<n;++i) {
		cin >> a.at(i);
		a.at(i)--;
	}
}
void DFS(vector<vector<int> > & Ad,
		 vector<int> & D,
		 vector<int> & F,
		 int & time,
		 int idx)
{
	if (F[idx] < 0) {
		for(int i=0;i<(int)Ad[idx].size();++i) {
			int next = Ad[idx][i];
			if (D[next] < 0) {
				D[next] = time++;
				DFS(Ad,D,F,time,next);
			}
		}
		F[idx]= time++;
	}
}
int main(){
	int n;
	cin >> n;
	vector<vector<int> > Ad(n);
	vector<int> D(n,-1),F(n,-1);
	for(int k=0;k<n;++k) {
		int u;
		cin >> u;
		--u;
		InputSet(Ad[u]);
	}
	int time=1;
	for(int i=0;i<n;++i) {
		if (D[i] < 0) {
			D[i] = time++;
			DFS(Ad,D,F,time,i);
		}
	}

	for(int i=0;i<n;++i){
		cout << i + 1 << " " << D[i] << " " << F[i] << endl;
	}
}

C++: #define scanf_s scanf
#include <string>
#include <stdio.h>
#include <math.h>
#include <stack>
#include <queue>
#include <list>
#include <vector>
#include <iostream>
using namespace std;

#define MAX 100
//#define MAX_ 1000
struct Graph
{
	int id, k = 0;
	list<int> node;
	int d = 0, f = 0;
};
Graph G[MAX];
int cou = 1;
void Depth(Graph *g)
{
	if (g->k >= 0) {
		if (!(g->d)) {
			g->d = cou;
			++cou;
		}
		for (auto i = g->node.begin(); i != g->node.end(); ++i) {
			Depth(&G[*i]);
		}
		if (!(g->f)) {
			g->f = cou;
			++cou;
		}
	}
}

int main(void)
{
	int n, u, xk, v;
	scanf_s("%d", &n);
	for (int i = 0; i < n; ++i) {
		scanf_s("%d %d", &u, &xk);
		G[u - 1].id = u - 1;
		G[u - 1].k = xk;
		for (int j = 0; j < xk; ++j) {
			scanf_s("%d", &v);
			G[u - 1].node.push_back(v - 1);
		}
	}
	Depth(&G[0]);
	for (int i = 0; i < n; ++i) {
		printf("%d %d %d\n", G[i].id + 1, G[i].d, G[i].f);
	}
}