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 <cstring>

using namespace std;

int n, u, k, v, d[110], f[110], tim=0;
bool vis[110];
vector<int> adj[110];

void dfs (int p)
{
    tim++;
    vis[p]=true;
    d[p]=tim;
    for (auto u : adj[p])
    {
        if (!vis[u]) dfs(u);
    }
    tim++;
    f[p]=tim;
}

int main()
{
    memset(vis, false, sizeof(vis));
    cin>>n;
    for (int i=0; i<n; i++)
    {
        cin>>u>>k;
        for (int j=0; j<k; j++)
        {
            cin>>v;
            adj[u].push_back(v);
        }
    }
    for (int i=1; i<=n; i++)
    {
        if (!vis[i]) dfs(i);
    }
    for (int i=1; i<=n; i++)
    {
        cout<<i<<' '<<d[i]<<' '<<f[i]<<'\n';
    }
    return 0;
}

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

using namespace std;
int n,u,k;

class points{
    public:
    int flag=0;
    list<int> l;
    int d=0;
    int f=0;
}pt[110];
int tem;

int times=0;

void dfa(int cur){
    times+=1;
    pt[cur].d=times;
    pt[cur].flag=1;
    while(!pt[cur].l.empty()){
        int dst=pt[cur].l.front();
            if(pt[dst].flag==0){
                dfa(dst);
            }
        pt[cur].l.pop_front();
    }
    times+=1;
    pt[cur].f=times;
}

int main(){
    cin>>n;
    for(int i=0;i<n;i++){
        cin>>u>>k;
        for(int j=0;j<k;j++){
            cin>>tem;
            pt[u].l.push_back(tem);
        }
    }
    for(int i=1;i<=n;i++){
        if(pt[i].flag==0){
            dfa(i);
        }
    }
    for(int i=1;i<=n;i++){
        cout<<i<<" "<<pt[i].d<<" "<<pt[i].f<<endl;
    }
    
}

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

static const int N = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int color[N], d[N], f[N], tt;
int nt[N];

int next(int M[N][N], int n, int u) {
    for (int v = nt[u]; v < n; ++v) {
        nt[u] = v + 1;
        if (M[u][v]) return v;
    }
    return -1;
}

void dfs_visit(int M[N][N], int n, int r) {
    for (int i = 0; i < n; ++i) nt[i] = 0;

    stack<int> S;
    S.push(r);
    color[r] = GRAY;
    d[r] = ++tt;

    while (!S.empty()) {
        int u = S.top();
        int v = next(M, n, u);
        if (v != -1) {
            if (color[v] == WHITE) {
                color[v] = GRAY;
                d[v] = ++tt;
                S.push(v);
            }
        } else {
            S.pop();
            color[u] = BLACK;
            f[u] = ++tt;
        }
    }
}
void dfs(int M[N][N], int n) {
    for (int i = 0; i < n; ++i) {
        color[i] = WHITE;
        nt[i] = 0;
    }
    tt = 0;

    for (int i = 0; i < n; ++i) {
        if (color[i] == WHITE) dfs_visit(M, n, i);
    }
    for (int i = 0; i < n; ++i) {
        cout << i + 1 << " " << d[i] << " " << f[i] << endl;
    }
}

int main() {

    int n;
    cin >> n;

    int M[N][N] = {0};
    int u, k, v;
    for (int i = 0; i < n; ++i) {
        cin >> u >> k;
        --u;
        for (int j = 0; j < k; ++j) {
            cin >> v;
            --v;
            M[u][v] = 1;
        }
    }

    dfs(M, n);

    return 0;
}

C++: #include<stdio.h>

#define WHITE 0   // not visited yet.
#define GRAY 1    // visited, but not completed.
#define BLACK 2   // search completed.

int G[101][101];        // adjacency list.
int color[101];         // visited/completed sign.
int n;                  // size.
int d[101], f[101], t;  // first visit time/complete time.

void search_loop(int i) 
{
    int next;
    d[i] = ++t;
    color[i] = GRAY;  // first visited.

    for(next = 1; next <= n; next++){
        if(i == next && G[i][i] > 0) break;   // if self-looped, through.
        if(G[i][next] > 0 && color[next] == WHITE){  // if not visited yet, visit.
            search_loop(next);
        }
    }
    f[i] = ++t;
    color[i] = BLACK;  // completed. 

    return;
}

void dfs()
{
    int i;
    for(i = 1; i <= n; i++) color[i] = WHITE;  // initialize.
    t = 0;

    for(i = 1; i <= n; i++) if(color[i] == WHITE) search_loop(i);

    for(i = 1; i <= n; i++) printf("%d %d %d\n", i, d[i], f[i]);

    return ;
}

int main()
{
    int i, j, k, e;
    scanf("%d", &n);
    for(i = 1; i <= n; i++){
        for(j = 1; j <= n; j++){ G[i][j] = 0; } }

    do{
        scanf("%d %d", &i, &e);
        for(j = 1; j <= e; j++){
            scanf("%d", &k);
            G[i][k] = 1;
        }
    }while(i < n);

    dfs();
    return 0;
}

C++: #include <iostream>
using namespace std;
int n,g[100][100],c[100],f[100],e[100],t=1;
void dfs(int now){
  c[now]=1;
  f[now]=t;
  t++;
  for(int i=0;i<n;i++) if(g[now][i]&&c[i]!=1){
      dfs(i);
      t++;
    }
  e[now]=t;
}
int main(){

  int a,b,tmp;
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>a>>b;
    for(int j=0;j<b;j++){
      cin>>tmp;
      g[a-1][tmp-1]=1;
    }
  }
  dfs(0);

  for(int i=0;i<n;i++) cout<<i+1<<" "<<f[i]<<" "<<e[i]<<endl;

  return 0;

}