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>
#include <algorithm>
#include <numeric>
#include <queue>
#include <stack>
#include <map>
#define FOR(i,b,e) for(int i=b;i<e;i++)
#define REP(i,n) FOR(i,0,n)
using namespace std;

const int N = 100;
int n;
int d[N+1], f[N+1], state[N+1], ns[N+1][N+1];
stack<int> s;

int next(int u) {
  FOR(i, 1, n+1) {
    if (ns[u][i] == 1 && state[i] == 0) return i;
  }
  return -1;
}
int main() {
	cin.tie(0);
 	ios::sync_with_stdio(false);

  cin >> n;

  FOR(i, 1, n+1) state[i] = 0;
  FOR(i, 1, n+1) {
    FOR(j, 1, n+1) {
      ns[i][j] = 0;
    }
  }

  REP(i, n) {
    int p, m;
    cin >> p; cin >> m;

    REP(j, m) {
      int pp; cin >> pp;
      ns[p][pp] = 1;
    }
  }

  int t = 1;

  s.push(1);
  state[1] = 1;
  d[1] = 1;
  while (!s.empty()) {
    t++;

    int p, np;
    p = s.top();
    if ((np = next(p)) != -1) {
      s.push(np);
      state[np] = 1;
      d[np] = t;
    } else {
      s.pop();
      state[p] = 2;
      f[p] = t;
    }
  }

  FOR(i, 1, n+1) {
    cout << i << " " << d[i] << " " << f[i] << endl;
  }
}

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

#define N 101

void DepthFirstSearch();

class stack{
public:
    int array[100];
    int top = -1;
    
    void push(int v) {
        top++;
        array[top] = v;
        return;
    }
    
    int pop() {
        top--;
        return array[top+1];
    }
    
    int show() {
        return array[top];
    }
};

typedef struct {
    int d;
    int f;
} P;

int n;
int t = 0;
int a[N][N] = {};
stack s;
P list[N];

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    cin>>n;
    
    int u, k, v;
    for(int i = 0; i < n; i++) {
        cin>>u>>k;
        
        for(int j = 0; j < k; j++) {
            cin>>v;
            a[u][v] = 1;
        }
    }
    
    for(int i = 1; i <= n; i++) {
        if(list[i].d == 0) {
            s.push(i);
            for(int j = 1; j <= n; j++) a[j][i] = 0;
            DepthFirstSearch();
            s.pop();
        }
    }
    
    for(int i = 1; i <= n; i++) {
        cout<<i<<' '<<list[i].d<<' '<<list[i].f<<endl;
    }
    
    return 0;
}

void DepthFirstSearch() {
    t++;
    int u = s.show();
    list[u].d = t;
    for(int i = 1; i <= n; i++) {
        if( a[u][i] == 1 ) {
            s.push(i);
            a[u][i] = 0;
            for(int j = 1; j <= n; j++) a[j][i] = 0;
            DepthFirstSearch();
            s.pop();
        }
    }
    t++;
    list[u].f = t;
}

C++: #include<bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vs = vector<string>;
using msi = map<string, int>;
using mii = map<int, int>;
using psi = pair<string, int>;
using pii = pair<int, int>;
using vlai = valarray<int>;
#define rep(i,n) for(int i=0;i<n;i++)
#define range(i,s,n) for(int i=s;i<n;i++)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define fs first
#define sc second
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define INF 1E9
#define EPS 1E-9
#define MOD (ll)(1E9+7)
#define PI 3.1415926535897932384

template <class T>ostream &operator<<(std::ostream &o, const vector<T> &v)
{
	rep(i, v.size()) {
		o << (i > 0 ? " " : "") << v[i];
	}
	return o;
}
int n,t=0;
vvi a;
vi d;
vi f;

void Depth(int pos) {
	if (d[pos] == 0) {
		d[pos] = ++t;
	}
	rep(i, n) {
		if (a[pos][i] == 1) {
			Depth(i);
		}
	}
	if (f[pos] == 0) {
		f[pos] = ++t;
	}
}


int main() {
	cin >> n;
	a.resize(n, vi(n, 0));
	d.resize(n, 0);
	f.resize(n, 0);
	rep(i, n) {
		int num,m;
		cin >>num >>m;
		rep(i, m) {
			int tmp;
			cin >> tmp;
			a[num - 1][tmp - 1] = 1;
		}
	}
	Depth(0);
	rep(i, n) {
		cout << i + 1 << " " << d[i] << " " << f[i] << endl;
	}
}

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

using namespace std;

void dfs(int v,vector<vector<int>>& vertex, int d[], int f[]);

int cnt = 1;

int main(){
    int n;
    cin >> n;
    int num;
    int tmp2;
    int d[n] = {};
    int f[n] = {};
    vector<vector<int>> vertex;
    vector<int> tmp;
    for(int i=0;i<n;i++){
        cin >> num;
        cin >> num;
        for(int j=0;j<num;j++){
            cin >> tmp2;
            tmp.push_back(tmp2-1);
        }
        vertex.push_back(tmp);
        tmp.clear();
    }
    dfs(0, vertex, d, f);
    for(int i=0;i<n;i++){
        if(d[i]==0){
            dfs(i, vertex, d, f);
        }
    }
    for(int i=0;i<n;i++){
        cout << i+1 << " " <<  d[i] << " " << f[i] << endl;
    }
    return 0;
}

void dfs(int v, vector<vector<int>>& vertex, int d[], int f[]){
    d[v] = cnt++;
    for(int i : vertex[v]){
        if(d[i]==0){
            dfs(i, vertex, d, f);
        }
    }
    f[v] = cnt++;
}