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++: //深度优先搜索 ,递归实现 
#include <iostream>

using namespace std;

const int N = 100;

const int NIL = -1;

int n;
bool graph[N+1][N+1] = {false}; //关系矩阵图 
char *color;//标记点的状态 B代表访问结束，W代表未访问，G代表正在访问 
int *d; //首次发现该点的时间 
int *f;  //结束访问该点的时间 

int mtime = 0; //当前的时间 


//递归的深度优先搜索 
void dfs(int u) {
	color[u] = 'G';
	d[u] = ++mtime;
	for (int j = 1;j<=n;j++) {
		if (graph[u][j] && color[j] == 'W') {
			dfs(j);
		}
	}
	color[u] = 'B';
	f[u] = ++mtime;
} 

int main() {
	cin >> n;
	color = new char[n+1]; 
	d = new int[n+1];
	f = new int[n+1];
	
	//初始化 
	for (int i = 1;i<=n;i++) {
		color[i] = 'W';
		d[i] = 0;
		f[i] = 0;
	}
	
	for (int i=0;i<n;i++) {
		int x,k;
		cin >> x >> k;
		for (int j = 0;j<k;j++) {
			int y;
			cin >> y;
			graph[x][y] = true; 
		}
	}
	
	for (int i = 1;i<=n;i++) {
		if (color[i] == 'W') {
			dfs(i);
		}
	}
	
	for (int i = 1;i<=n;i++) {
		cout << i << " " << d[i] << " " << f[i] << endl;
	}
	
	delete[] color;
	delete[] d;
	delete[] f;
}

C++: #include<stdio.h>
 
#define MAX 100
#define WHITE -1
#define GRAY 0
#define BLACK 1
 
int n,t;
int color[MAX],d[MAX],f[MAX],Adj[MAX][MAX];
 
dfs(){
  int i;
 
  for(i=0;i<n;i++) color[i]=WHITE;
  t=0;
  for(i=0;i<n;i++){
    if(color[i]==WHITE) visit(i);
  }
}
 
visit(int r){
  int i;
 
  color[r]=GRAY;
  d[r]=++t;
 
  for(i=0;i<n;i++){
    if(Adj[r][i]==1 && color[i]==WHITE) visit(i);
  }
 
  color[r]=BLACK;
  f[r]=++t;
}
 
int main(){
  int i,u,k,j,v;
 
  for(i=0;i<MAX;i++){
    for(j=0;j<MAX;j++){ 
      Adj[i][j]=0;
    }
  }
 
  scanf("%d",&n);
  for(i=0;i<n;i++){
    scanf("%d%d",&u,&k);
    for(j=0;j<k;j++){
      scanf("%d",&v);
      Adj[u-1][v-1]=1;
    }
  }
 
  dfs();
 
  for(i=0;i<n;i++){
    printf("%d %d %d\n",i+1,d[i],f[i]);
  }
 
  return 0;
}

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

#define WHITE 0
#define GRAY 1
#define BLACK 2

int main ()
{
    int N;
    cin >> N;

    int M[N][N];
    int D[N], F[N], C[N];

    for (int i = 0; i < N; i++)
    {
        D[i] = 0;
        F[i] = 0;
        C[i] = WHITE;
        
        for (int j = 0; j < N; j++)
        {
            M[i][j] = 0;
        }
    }

    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--;
            M[u][v] = 1;
        }
    }


    for (int i = 0; i < N; i++)
    {
        for (int j = 0; j < N; j++)
        {
            if (j > 0)
                cout << " ";
            cout << M[i][j];
        }
        cout << endl;
    }

    stack<int> *S = new stack<int>;

    int time = 0;

    S->push(0);
    C[0] = GRAY;
    D[0] = ++time;

    while (S->size() > 0)
    {
        int u = S->top();
        int v = -1;

        // next 
        for (int i = 0; i < N; i++)
        {
            int flag = M[u][i];

            if (flag == 1)
            {
                if (C[i] == WHITE)
                {
                    v = i;
                    break;
                }
            }
        }

        if (v != -1)
        {
            if (C[v] == WHITE)
            {
            C[v] = GRAY;
            D[v] = ++time;
            S->push(v);
            }
        }
        else
        {
            S->pop();
            C[u] = BLACK;
            F[u] = ++time;
        }
    }

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

C++: #include <bits/stdc++.h>
using namespace std;
#define MAX 101
int m[MAX][MAX],d[MAX],f[MAX],tt,n,book[MAX];

void dfs_vis(int s)
{
	book[s]=0;
	d[s]=++tt;
	for(int i=1;i<=n;i++)
	{
		if(!m[s][i]) continue;
		if(book[i]) dfs_vis(i);
	}
	f[s]=++tt;
}

void dfs()
{
	for(int i=1;i<=n;i++) book[i]=1;
	for(int i=1;i<=n;i++) if(book[i]) dfs_vis(i);
	for(int i=1;i<=n;i++) cout<<i<<" "<<d[i]<<" "<<f[i]<<endl;
}
int main()
{
	int u,k,t;
	scanf("%d",&n);
	for(int i=0;i<n;i++)
	{
		cin>>u>>k;
		for(int j=0;j<k;j++)
		{
			cin>>t;
			m[u][t]=1;
		}
	}	
	dfs();
	return 0;
}

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

void dfs_visit(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;
		for(v = 0; v < n; v++) {
			if(M[u][v] == 0) continue;
			if(color[v] != WHITE) continue;
			break; 
		}
		if(v != n) {
			if(color[v] == WHITE) {
			   color[v] = GRAY;
			   d[v] = ++tt;
			   S.push(v); 	
		    }
		} 
		for(v = 0; v < n; v++) {
			if(M[u][v] == 1) break;
		}
		if(v == n){
		   color[u] = BLACK;
		   S.pop();
		   f[u] = ++tt;
		}
	} 
}


void dfs() {
	for(int i = 0; i < n; i++) {
	     color[i] = WHITE;
	}
	tt = 0;
		
	for(int u = 0; u < n; u++) {
		if(color[u]) dfs_visit(u);
	}

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

int main() {
	int k , u, 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;
}