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>

using namespace std;

const int kSize = 101;

vector<int> adj[kSize];
bool isMarked[kSize];
int d[kSize];
int f[kSize];
int t = 1;

void dfs(int v) {
    isMarked[v] = true;
    d[v] = t;
    t++;

    for (int i = 0; i < adj[v].size(); ++i) {
        int u = adj[v][i];
        if (!isMarked[u]) {
            dfs(u);
        }
    }
    f[v] = t;
    t++;
}

int main() {
    int n;
    fill(isMarked, isMarked + kSize, false);
    cin >> n;
    for (int i = 0; i < n; ++i) {
        int id, k;
        cin >> id >> k;
        for (int j = 0; j < k; ++j) {
            int v;
            cin >> v;
            adj[id].push_back(v);
        }
    }

    //dfs(1);
    for (int i = 1; i <= n; ++i) {
        if (!isMarked[i]) {
            dfs(i);
        }
    }
    for (int i = 1; i <= n; ++i) {
        cout << i << " " << d[i] << " " << f[i] << endl;
    }

    return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<string>
#include<algorithm>
#include<cstring>
#include<vector>
#include<stack>
using namespace std;
#define INT(x) int x; scanf("%d",&x)
#define INPUT(x) scanf("%d",&x)
#define REP1(x,n) for(int x = 0; x < n; x++)
#define REP2(x,s,e) for(int x = s; x <= e; x++)
#define BR printf("\n")
#define INF 2000000000

vector<int> V[100];//0 origin
bool complete[100] = {};
stack<int> S;
int time_ = 1;
int NodeStump[100][2];//find,end

void DFS(){
    NodeStump[S.top()][0] = time_;
    time_++;//d++
    if (S.empty()) return;
    
    REP1(i,V[S.top()].size()){
        if (!complete[V[S.top()][i]]){
            S.push(V[S.top()][i]);
            DFS();
        }
    }
    
    complete[S.top()] = true;
    NodeStump[S.top()][1] = time_;
    S.pop();
    time_++;//d--
}

int main(){
    INT(N);
    
    REP1(i,N){
        int from,n;
        scanf("%d %d",&from,&n);
        REP1(j,n){
            INT(to);
            V[i].push_back(to - 1);
        }
    }
    
    S.push(0);
    
    DFS();
    
    REP1(i,N){
        printf("%d %d %d\n",i+1,NodeStump[i][0],NodeStump[i][1]);
    }
    
    return 0;
}

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

using namespace std;

int  n, M[100][100], d[100], f[100], color[100], time, nt[100], W = 0, G = 1, B = 2;

int next (int u) {

    int v;
    for (v = nt[u]; v < n; v++) {
        nt[u] = v + 1;
        if (M[u][v] != 0) {
            return v;
        }
    }
    return -1;

}

void dfs_visit (int r) {

    int i, u, v;

    for (i = 0; i < n; i++) {
        nt[i] = 0;
    }

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

    while (!S.empty()) {
        u = S.top();
        v = next (u);
        if (v != -1) {
            if (color[v] == W) {
                color[v] = G;
                d[v] = ++time;
                S.push(v);
            }
        } else {
            S.pop();
            color[u] = B;
            f[u] = ++time;
        }
    }

}

void dfs () {

    int i, u;

    for (i = 0; i < n; i++) {
        color[i] = W;
        nt[i] = 0;
    }
    time = 0;

    for (u = 0; u < n; u++) {
        if (color[u] == W) {
            dfs_visit(u);
        }
    }

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

}

int main () {

    int u, k, v, i, j;

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

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

    dfs ();

    return 0;

}

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

using namespace std;

std::vector<int> graph[100];
int d[100],f[100];
int t = 0;

void dfs(int v){
  t++;
  d[v] = t;
  for(const auto &next_v:graph[v]){
    if(d[next_v]==0){
      dfs(next_v);
    }
  }
  t++;
  f[v] = t;
}

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

C++: #include<stdio.h>

#define BLACK -1
#define GRAY  -2
#define WHITE -3

void DFSvisit(int);

int G[100][100],d[100],f[100],color[100];
int n,time;

void DFS(int n){
  int i;

  for(i=0;i<n;i++){
    if(color[i]==WHITE){
      DFSvisit(i);
    }
  }
}

void DFSvisit(int u){
  int i;

  color[u]=GRAY;
  time++;
  d[u]=time;

  for(i=0;i<=n;i++){
    if(G[u][i] && color[i]==WHITE){
      DFSvisit(i);
    }
  }
  color[u]=BLACK;
  f[u]=++time;
}

main(){
  int  i,j,k,m;

  scanf("%d",&n);

  for(i=0;i<100;i++){
    for(j=0;j<100;j++){
      G[i][j]=0;
    }
    color[i] = WHITE;
  }

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

  for(i=0;i<n;i++){
    printf("%d %d %d\n",i+1,d[i],f[i]);
  }
  return 0;
}