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 <bits/stdc++.h>
#include <math.h>

using namespace std;

long long inf=1000000007;
vector<bool> seen(10000,false);

void dfs(long long &cnt,long long now,vector<long long> &d,vector<long long> &f,vector<vector<long long>> kankei){
	seen.at(now)=true;
	cnt++;
	d.at(now)=cnt;

	for(auto a:kankei.at(now)){
		if(seen.at(a)) continue;

		dfs(cnt,a,d,f,kankei);
	}

	cnt++;
	f.at(now)=cnt;

	return;
}

int main(){
	long long n;
	cin>>n;
	vector<vector<long long>> kankei(n+1);

	for(long long i=1;i<=n;i++){
		long long k,u;
		cin>>k>>u;
		vector<long long> vec(u);
		for(long long j=0;j<u;j++){
			cin>>vec.at(j);
		}
		sort(vec.begin(),vec.end());

		kankei.at(k)=vec;
	}

	vector<long long> d(n+1,0);
	vector<long long> f(n+1,0);
	long long cnt=0;

	for(long long i=1;i<=n;i++){
		if(seen.at(i)) continue;

		dfs(cnt,i,d,f,kankei);
	}

	for(long long i=1;i<=n;i++){
		cout<<i<<" "<<d.at(i)<<" "<<f.at(i)<<endl;
	}

	return 0;
}

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

#define MAX_N 101

int counter;
int d[MAX_N];
int f[MAX_N];

void DFS(list<int>* G, int n){
	counter++;
	d[n] = counter;
	list<int>::iterator it;
	for(it=G[n].begin(); it!=G[n].end(); it++){
		if(d[*it-1]==0) DFS(G, *it-1);
	}
	counter++;
	f[n] = counter;
}

int main()
{
	counter = 0;
	for(int i=0; i<MAX_N; i++) d[i]=f[i]=0;
	int n;cin>>n;
	list<int> G[n];
	
	// input Graph data
	for(int i=0; i<n; i++){
		int u, k, v;
		cin >> u >> k;
		for(int j=0; j<k; j++){
			cin >> v;
			G[u-1].push_back(v);
		}
	}
	// DFS
	for(int i=0; i<n; i++){
		if(d[i]==0){
			DFS(G, i);
		}
	}
	// Output Result
	for(int i=0; i<n; i++){
		cout << i+1 << " " << d[i] << " " << f[i] << endl;
	}

	return 0;
}

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

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

  int V[100][100]; //隣接リスト
  int cnt[100];　//各点においてどこまでみたかの把握
  int d[100];
  int f[100];
  int time=1;
  int l=0;
  int come[100]; //その点はどこからきたかの把握

  //初期化
  for(int i=0;i<100;i++){
    for(int j=0;j<100;j++){
      V[i][j]=0;
      cnt[j]=0;
      d[j]=0;
      f[j]=0;
      come[j]=0;
    }
  }
  //グラフ情報の読み込み
 int  m=0;
  for(int i=0;i<n;i++){
    cin>>u;
    cin>>k;
    for(int j=0;j<k;j++){
      cin>>v;
      V[u-1][m]=v;
      m++;
    }
    m=0;
  }


  //スタートは0
 d[0]=1;
 time++;
  while(1){

    if(time==2*n+1) break;
    //先がありかつそこは探索終了していない
    if(V[l][cnt[l]]!=0 && f[V[l][cnt[l]]-1]==0){ 
     
      if(d[V[l][cnt[l]]-1]==0) d[V[l][cnt[l]]-1]=time;

   come[V[l][cnt[l]]-1]=l;
      cnt[l]++;
      l=V[l][cnt[l]-1]-1; 

      time++;
      //先がないまたはさきが探索終了している
    }else{

      if(d[l]==0) d[l]=time;
       f[l]=time;
      l=come[l];
      time++;

    }

  }
  /*
  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
    cout<<V[i][j]<<" ";
    if(j==n-1) cout<<endl;
  }
  }
  */
  //出力
  for(int i=0;i<n;i++){

    cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
    }


  return 0;
}

C++: #include <iostream>
#include <stack>
using namespace std;
static const int N=100;
static const int WHITE=1;
static const int GRAY=2;
static const int BLACK=3;

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

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++) ;
    stack<int> S;
    S.push(r);
    color[r]=GRAY;
    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 u=0;u<n;u++)
    {
        if(color[u]==WHITE) dfs_visit(u);
    }

    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 j=0;j<k;j++)
        {
            cin>>v;
            v--;
            M[u][v]=1;
        }
    }
    dfs();
    return 0;
}

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

void dfs(vector<vector<int> > &G, vector<bool> &seen, vector<int> &d, vector<int> &f, int v, int &t) {
    seen[v] = true;
    d[v] = ++t;
    for (int i = 0; i < G[v].size(); i++) {
        if (seen[G[v][i]]) continue;
        dfs(G, seen, d, f, G[v][i], t);
    }
    f[v] = ++t;
}

void print(int n, vector<int> &d, vector<int> &f) {
    for (int i = 0; i < n; i++) {
        cout << i + 1 << " " << d[i] << " " << f[i] << endl;
    }
}

int main() {
    int n;
    cin >> n;
    vector<vector<int> > G(n);
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        u--;
        for (int j = 0; j < k; j++) {
            int v;
            cin >> v;
            v--;
            G[u].push_back(v);
        }
    }

    vector<bool> seen(n, false);
    vector<int> d(n), f(n);
    int t = 0;
    for (int i = 0; i < n; i++) {
        if (seen[i]) continue;
        dfs(G, seen, d, f, i, t);
    }
    print(n, d, f);

    return 0;
}