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 <algorithm>
#include <vector>
#include <string>
#include <set>
#include <queue>
#include <cmath>
#include <map>

using namespace std;
vector<pair<int,int> > ans(100);
vector<vector<int> > da(100);
vector<bool> ju(100,false);

void dfs(int m,int &ti){
    bool ch=true;
    for(int i=0;i<da[m].size();i++){
        if(!ju[da[m][i]]){
            ju[da[m][i]]=true;
            ch=false;
            ti++;
            ans[da[m][i]].first=ti;
            dfs(da[m][i],ti);
        }
    }
    ti++;
    ans[m].second=ti;
}

int main(){
    int n,ti=0;
    cin >> n;
    for(int i=0;i<n;i++){
        int x;
        cin >> x;
        int y;
        cin >> y;
        vector<int> iin(y);
        for(int j=0;j<y;j++){
            cin >>iin[j];
            iin[j]--;
        }
        da[x-1]=iin;
    }
    for(int i=0;i<n;i++){
        if(!ju[i]){
            ju[i]=true;
            ti++;
            ans[i].first=ti;
            dfs(i,ti);
        }
    }
    for(int i=0;i<n;i++){
        cout << i+1 << ' ' << ans[i].first << ' ' << ans[i].second << 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 M[N][N], color[N], d[N], f[N], nt[N];
int tt,n;

int next(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 r) {
	for(int i = 0; i < n; i++) nt[i] = 0;
	
	stack<int> S;
	S.push(r);
	color[r] = BLACK;
	d[r] = ++tt;
	
	while(!S.empty()) {
		int u = S.top();
		int v = next(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() {
	for(int i = 0; i < n; i++){
		color[i] = WHITE; nt[i] = 0;
	}
	tt = 0; 
	
	for(int j = 0; j < n; j++) {
		if(color[j] == WHITE) {
			dfs_visit(j);
		}
	}
	
	for(int i =0; i < n; i++ ) {
    	cout << i+1 << " " << d[i] << " " << f[i] << endl;
	}
}


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

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


using namespace std;

int N;
int D[100+10] = {};
int U = 0;
int K[100+10] = {0};
int V = -1;
int G[100+10][100+10] = {0};
int curtime_st[100+10] = {0};
int curtime_en[100+10] = {0};



//stack dst   queue bfs


int time_ = 1;
int prev1 = 0;
int prev_b = 0;
void dfs(int cur){
  if (cur == -1)return;//??¢??±
  if (curtime_st[cur] == 0)curtime_st[cur] = time_;

  D[cur] = 0;
  time_ += 1;
  //
  //cerr << "visiting " << cur << " " << time_ - 1  << endl;
  
  for(int dst=1;dst<=N;++dst){
    if(D[dst] == -1 && G[cur][dst] == 1){
      dfs(dst);
	}
  }
  if(curtime_en[cur] == 0 || curtime_en[cur] == curtime_st[cur])curtime_en[cur] = time_;
  time_ += 1;
  return;
}







int main(){
  cin >> N;

  for(int i=0;i<101;++i){
    D[i] = -1;//?????????
  }

  for(int i=0;i<N;++i){
    cin >> U;
    cin >> K[U];
    for(int j=0;j<K[U];++j){
      cin >> V;
      G[U][V] = 1;
    }
  }

  for(int j=1;j<=N;++j){
    for(int i=1;i<=N;++i){
      //cout << G[i][j] << " ";
    }
    //cout << endl;
  }

  dfs(1);
  for(int i=2;i<=N;++i){
    if(D[i] == -1)dfs(i);
  }

  for(int i=1;i<=N;++i){
    cout << i << " " << curtime_st[i] << " " << curtime_en[i] << endl; 
  }
}

C++: #include <iostream>

using namespace std;

int graph[101][101]={};
int d[101]={};
int f[101]={};
int n,v,k,time1 = 0,sw[101] = {};


void dfs1(int u){

  sw[u] = 1;
  d[u] = ++time1;

  for(int i = 1; i <= n; i++){
    if( graph[u][i] == 1 && sw[i] == 0 ){
     dfs1(i);
    }

  }
    f[u] = ++time1;
}


int main(){
  int u;
  cin >> n ;
  //グラフをつくる
  for(int i = 0; i < n; i++){
    cin >> u >> k ;
    for(int j = 0; j < k ; j++){
      cin >> v;
      graph[u][v] = 1;
    }
  }
 
 for(int i = 1; i <= n; i++){
    if(sw[i] == 0){
      dfs1(i);
	}
  }

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

  }
}

C++: #include <bits/stdc++.h>
using namespace std;
#define _GLIBCXX_DEBUG
using ll = long long;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int t=0;

void dfs(vector<vector<int>> &vec, vector<pair<int, int>> &stmp, int now) {
  if (stmp[now].first) return;
  ++t;
  stmp[now].first = t;

  rep (i, vec[now].size()) dfs(vec, stmp, vec[now][i]);
  

  ++t;
  stmp[now].second = t;
  return;
}
     
int main() {
  int n, k;
  cin >> n;
  vector<vector<int>> vec(n, vector<int>(1));
  vector<pair<int, int>> stmp(n, make_pair(0, 0));
  set<int> s;
  rep (i, n) {
    int voii;
    cin >> voii;
    cin >> k;
    vec[i].resize(k);
    rep (j, k) {
      int x;
      cin >> x;
      vec[i][j] = x - 1;
    }
  }

  rep (i, n) {
    dfs(vec, stmp, i);
  }

  rep (i, n) printf("%d %d %d\n", i + 1, stmp[i].first, stmp[i].second);
}