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 MAX = 101;

vector<int> G[MAX];
int d[MAX], f[MAX];
int *T;

void dfs(int u) {

    if (!d[u]) d[u] = ++(*T);

    for (int v : G[u]) {
        if (!d[v]) d[v] = ++(*T);
        dfs(v);
    }

    if (!f[u]) f[u] = ++(*T);
}

int main() {

    int n;
    cin >> n;

    int t = 0;
    T = &t;
    fill(d, d + MAX, 0);
    fill(f, f + MAX, 0);

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

    for (int i = 1; i <= n; i++) {
        if (!d[i]) dfs(i);
    }


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

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

using namespace std;
struct node {
    node() {};
    node(int i, int n, int* xs) : id {i}, ns {vector<int>(xs, xs+n)} {
        delete xs;
    };
    int id;
    vector<int> ns;
    int in_time;
    int out_time;
};

int dfs(map<int, node*> graph, int time, int id){
    node* n = graph[id];
    if(n->in_time > 0){
        return time;
    }
    n->in_time = ++time;
    vector<int> ns = n->ns;
    for(auto it = ns.begin(); it != ns.end(); ++it){
        time = dfs(graph, time, *it);
    }
    n->out_time = ++time;
    return time;
}

int main(){
    int n;
    cin >> n;
    map<int, node*> graph {};
    int st = 1000000000;
    for(int i = 0; i < n; ++i){
        int id;
        cin >> id;
        st = min(st, id);
        int k;
        cin >> k;
        int* ns = new int[k];
        for(int j = 0; j < k; ++j){
            cin >> ns[j];
        }
        graph[id] = new node(id, k, ns);
    }
    int time = 0;
    for(auto it = graph.begin(); it != graph.end(); ++it){
        pair<int, node*> p = *it;
        if(p.second->in_time){
            continue;
        }
        time = dfs(graph, time, p.first);
    }
    for(auto it = graph.begin(); it != graph.end(); ++it){
        pair<int, node*> p = *it;
        cout << p.first << ' ' << p.second->in_time << ' ' << p.second->out_time << endl;
    }
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
#define WHITE 0
#define GRAY 1
#define BLACK 2
vector<vector<int>> M(100, vector<int>(100));
vector<int> C(100);
int n, tt;
vector<int> ST(100), PT(100);

int next(int u) {
  rep(i, n) {
    if (M.at(u).at(i) == 1 && C.at(i) == WHITE) {
      return i;
    }
  }
  return -1;
}

void dfs_visit(int u) {
  stack<int> S;
  S.push(u);
  ST.at(u) = ++tt;
  C.at(u) = GRAY;
  while (S.size() > 0) {
    int t = S.top();
    int v = next(t);
    if (v!=-1) {
      if (C.at(v) == WHITE) {
        S.push(v);
        ST.at(v) = ++tt;
        C.at(v) = GRAY;
      }
    } else {
      S.pop();
      PT.at(t) = ++tt;
      C.at(t) = BLACK;
    }
  }
}

void dfs() {
  tt = 0;
  rep(u, n) if (C.at(u) == WHITE) dfs_visit(u);
}

int main() {
  cin >> n;
  rep(i, n) {
    int id, k; cin >> id >> k;
    rep(j, k) {
      int num; cin >> num;
      M.at(id-1).at(num-1) = 1;
    }
  }
  dfs();

  rep(i,n) cout << i+1 << " " << ST.at(i) << " " << PT.at(i) << endl;
  return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <cstring>
#include <stack>
using namespace std;
const int maxx = 110;
int n, m[maxx][maxx];
int u, num, v;
int d[maxx], f[maxx];
int flag[maxx];
int nowtime = 1;

void dfs(int u) {

	// ??\?????¶??´
	flag[u] = 1;
	d[u] = nowtime++;
	for (int i = 1; i <= n; i++) {
		if (flag[i] == 0 && m[u][i] == 1) {
			dfs(i);
		}
	}
	//????????¶??´
	f[u] = nowtime++;
}

int main()
{

	scanf("%d", &n);
	memset(m, 0, sizeof(m));
	memset(f, 0, sizeof(f));
	for (int i = 1; i <= n; i++) {
		scanf("%d %d", &u, &num);
		for (int j = 1; j <= num; j++) {
			scanf("%d", &v);
			m[u][v] = 1;
		}
	}
	for (int i = 1; i <= n; i++) {
		if(flag[i] == 0)
			dfs(i);
	}
	for (int i = 1; i <= n; i++) {
		printf("%d %d %d\n", i, d[i], f[i]);
	}
	return 0;
}

C++: #include<iostream>
#include<cstring>
#include<vector>
#define rep(i, n) for (int i = 0; i < n; i++)
#define rrep(i, n) for (int i = n - 1; i >= 0; i--)
using namespace std;
//using Graph = vector<vector<int>>;
typedef long long ll;
typedef pair<long long,int> P;


int n, t = 0;
vector<int> g[105];
bool seen[105];
int d[105], f[105];

void dfs(int v){
    seen[v] = true;
    d[v] = t;
    for(int nv : g[v]){
        if(seen[nv]) continue;
        t++;
        dfs(nv);
    }
    t++;
    f[v] = t;
}

int main(){
    cin >> n;
    rep(i, n){
        int a, b;
        cin >> a >> b;
        rep(j, b){
            int c;
            cin >> c;
            g[a].push_back(c);
        }
    }
    rep(k, n) g[0].push_back(k + 1);

    memset(seen, 0, sizeof(seen));
    dfs(0);

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