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<stack>
#include<queue>
using namespace std;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

struct Node{
	int color, d, f;
	queue<int> Q;
};

int main(){
	int n;
	cin >> n;
	Node node[n + 1];
	stack<int> move;
	for(int i = 1; i <= n; i++){
		int u, k, v;
		cin >> u >> k;
		node[u].color = WHITE;
		while(k--){
			cin >> v;
			node[u].Q.push(v);
		}
	}

	move.push(1);
	int tt = 1, p, next;
	node[1].color = GRAY;
	node[1].d = tt;
	tt++;

	while(!move.empty()){
		p = move.top();
		if(node[p].Q.empty()){
			node[p].color = BLACK;
			node[p].f = tt;
			move.pop();
			tt++;
		} else {
			next = node[p].Q.front();
			if(node[next].color == WHITE){
				move.push(next);
				node[next].color == GRAY;
				node[next].d = tt;
				tt++;
			} else {
				node[p].Q.pop();
			}
		}
	}

	for(int i = 1; i <= n; i++){
		cout << i << " " << node[i].d << " " << node[i].f << endl;
	}
	return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<vector>
#include<queue>
using namespace std;
 
int find_t[101],end_t[101];
vector<queue<int> > vec(101);
int flag[101];
int t=1;
 
void DFS(int);
void Print();
 
int main(int argc,char* argv[]){
  int n,id,cnt,x;
   
  memset(find_t,255,sizeof(find_t));
  memset(end_t,0,sizeof(end_t));
  memset(flag,0,sizeof(flag));
 
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>id>>cnt;
    flag[id]=0;
    queue<int> tmp;
    for(int l=0;l<cnt;l++){
      cin>>x;
      tmp.push(x);
    }
    vec[id]=tmp;
  }
   
  for(int i=1;i<=n;i++){
    if(flag[i]==0)
      DFS(i);
  }
  Print();
   
  return 0;
}
 
void DFS(int p){
  if(flag[p]==0){
    find_t[p]=t++;
    flag[p]=1;
  }
  else
    return;
     
  queue<int> tmp=vec[p];
  while(!tmp.empty()){
    DFS(tmp.front());
    tmp.pop();
  }
 
  end_t[p]=t++;
}
 
void Print(){
  for(int i=1;i<=100;i++){
    if(find_t[i]!=-1)
      printf("%d %d %d\n",i,find_t[i],end_t[i]);
  }
}

C++: #include<iostream>
#include<cstdio>
#define WHITE 0
#define GRAY 1
#define BLACK 2

using namespace std;

int n, M[101][101];
int color[101], count1[101], count2[101], t;

void dfs_visit(int u) {
	int v;
	color[u] = GRAY;
	t++;
	count1[u] = t;
	for (v = 1; v <= n; v++) {
		if (M[u][v] == 0) {
			continue;
		}

		if (color[v] == WHITE) {
			dfs_visit(v);
		}
	}
	color[u] = BLACK;
	t++;
	count2[u] = t;
}

void dfs() {
	int u;
	for (u = 1; u <= n; u++) {
		color[u] = WHITE;
		t = 0;
	}
	for (u = 1; u <= n; u++) {
		if (color[u] == WHITE) {
			dfs_visit(u);
		}
	}
	for (u = 1; u <= n; u++) {
		printf("%d %d %d\n", u, count1[u], count2[u]);
	}
}

int main() {
	int u, v, k, i, j;
	cin >> n;

	for (i = 0; i <= n; i++) {
		for (int j = 0; j <= n; j++) {
			M[i][j] = 0;
		}
	}

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

	dfs();

	return 0;
}

/*
6
1 2 2 3
2 2 3 4
3 1 5
4 1 6
5 1 6
6 0
*/

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

const int MAX_N = 100;
vector<int> G[MAX_N];
int d[MAX_N], f[MAX_N];
bool used[MAX_N];

int stamp;

void dfs(const int v) {
    d[v] = stamp++;
    used[v] = true;
    for(int i = 0; i < (int)G[v].size(); i++) {
        int u = G[v][i];
        if(used[u] == false) dfs(u);
    }
    f[v] = stamp++;
}

int main() {
    int N; cin >> N;
    for(int i = 0; i < N; i++) {
        int u, k; cin >> u >> k; u--;
        while(k--) {
            int v; cin >> v; v--;
            G[u].push_back(v);
        }
        sort(G[u].begin(), G[u].end());
    }

    fill(used, used + N, false);
    stamp = 1;
    dfs(0);

    for(int i = 0; i < N; i++) {
        cout << i + 1 << ' ' << d[i] << ' ' << f[i] << endl;
    }
}

C++: #include <iostream>
#include <algorithm>
#include <stack>
#include <queue>
#include <vector>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>

using namespace std;

struct Node {
	int k, d, f;
	vector<int> v;
};

#define MAX_N 100

Node node[MAX_N + 1];
int _d, _f;

void dfs(int u) {
	if (node[u].d == 0) node[u].d = _d++;
	for (int i = 0; i < node[u].k; ++i)
		dfs(node[u].v[i]);
	if (node[u].f == 0) node[u].f = _f++;
}

int main() {
	int n;
	cin >> n;
	for (int i = 0; i < n; ++i) {
		int u;
		cin >> u;
		cin >> node[u].k;
		for (int j = 0; j < node[u].k; ++j) {
			int v;
			cin >> v;
			node[u].v.push_back(v);
		}
		node[u].d = node[u].f = 0;
	}
	_d = 1;
	_f = n + 1;
	dfs(1);
	for (int i = 1; i <= n; ++i)
		cout << i << " " << node[i].d << " " << node[i].f << endl;
	return 0;
}

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

struct Node{
  vector<int> AJ;
  bool visit;
  int d, f;
};

Node G[101];
int t = 0;

void dfs(int idx){
  G[idx].visit = true;
  G[idx].d = ++t;
  for(int i = 0; i < G[idx].AJ.size(); i++){
    if(!G[G[idx].AJ[i]].visit) dfs(G[idx].AJ[i]);
  }
  G[idx].f = ++t;
}

int main(){
  int n, u, k, v;
  cin >> n;
  for(int i = 0 ; i < 101; i++) G[i].visit = false;
  for(int i = 0; i < n; i++){
    cin >> u >> k;
    for(int j = 0; j < k; j++){
      cin >> v;
      G[u].AJ.push_back(v);
    }
  }
  for(int i = 1; i <= n; i++) if(!G[i].visit) dfs(i);
  for(int i = 1; i <= n; i++) cout << i << " " << G[i].d << " " << G[i].f << endl;
  return 0;
}