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++: #define _USE_MATH_DEFINES
#include<stdio.h>
#include<string>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include<iomanip>

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



using namespace std;




int main() {
	
	int n;
	cin>>n;
	vector<vector<int>>t(n,vector<int>(n));
	for(int i=0;i<n;i++){
		int x,r;cin>>r>>x;
		for(int j=0;j<x;j++){
			int w;cin>>w;w--;t[i].push_back(w);
		}
		sort(t[i].begin(),t[i].end());
	}
	stack<int>S;
	bool F[105]={};
	S.push(0);
	int p=1;
	F[0]=1;
	vector<int>G(n),H(n);
	int g=1;
	G[0]=1;
	while(S.size()){
		g++;
		int v=S.top();
		int a=-1;
		for(int i=0;i<t[v].size();i++){
			if(!F[t[v][i]]){
				a=t[v][i];break;
			}
		}
		if(a==-1){
			H[S.top()]=g;
			S.pop();
		}
		else{
			F[a]=1;
			G[a]=g;
			S.push(a);
		}
	}
	for(int i=0;i<n;i++){
		cout<<i+1<<" "<<G[i]<<" "<<H[i]<<endl;
	}
	

	
	return 0;
}

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

#define MAX 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

using namespace std;


int adjacencyList[MAX + 1][MAX + 1];
int color[MAX + 1];
int d[MAX + 1];
int f[MAX + 1];
int n;



int minWhiteNode(int v)
{

	for (int i = 1; i <= n; i++) {
		if (color[i] == WHITE && adjacencyList[v][i] == 1 && i != v) {
			return i;
		}
	}
	return 	MAX + 1;
}


void dfs()
{
	stack<int> S;
	int cr;
	int timer = 1;

	S.push(1);
	color[1] = GRAY;
	d[1] = 1;

	while (S.size() > 0) 
	{
		cr = minWhiteNode(S.top());
		timer++;

		if (cr != MAX + 1) {
			S.push(cr);
			color[cr] = GRAY;
			d[cr] = timer;
		}
		else {
			int poped = S.top();
			S.pop();
			color[poped] = BLACK;
			f[poped] = timer;
		}
	}
}

int main(void)
{

	int u;
	int k;
	int v;


	cin >> n;

	for (int i = 0; i < n; i++) {
		cin >> u >> k;

		for (int j = 0; j < k; j++) {
			cin >> v;
			adjacencyList[u][v] = 1;
		}

	}

	dfs();

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

	return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;
int t;

void dfs(vector<vector<bool> >& A, vector<vector<int> >& B, int s, int n){
    for(int i = 0; i < n; i++){
        if(i == 0){
            if(B[s][1] == 0){
                B[s][1] = t;
                t++;
            }
        }
        if(A[s][i] == true){
            A[s][i] = false;
            dfs(A, B, i, n);
        }
        if(i == n-1){
            if(B[s][2] == 0){
                B[s][2] = t;
                t++;
            }
        }
    }
}

int main(void){

    //??£??\??????????????£??\???????????????
    int n, k;

    cin >> n;
    vector<vector<bool> > A(n, vector<bool>(n, false));
    for(int i = 0; i < n; i++){
        cin >> k >> k;
        for(int j = 0; j < k; j++){
            int input;
            cin >> input;
            A[i][input-1] = true;
        }
    }

   

    vector<vector<int> > B(n, vector<int>(3, false));
    for(int i = 0; i < n; i++){
        B[i][0] = i + 1;
    }

    t = 1;
    for(int k = 0; k < n; k++){
        if(B[k][1] == 0) dfs(A, B, k, n);
    }
    

    //??????
    for(int i = 0; i < n; i++){
        for(int j = 0; j < 3; j++){
            if(j != 2) cout << B[i][j] << " ";
            else cout << B[i][j];
        }
        cout << endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>
#pragma GCC target("avx")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;
template<class T> inline bool chmax(T &a, T b) { if (a<b) {a=b; return 1;} return 0;}
template<class T> inline bool chmin(T &a, T b) { if (b<a) {a=b; return 1;} return 0;}

int n;
vector<vector<int>> to, timestamp;

void dfs(int v, int& t) {
    timestamp[v][0] = t++;
    for (int i = 0; i < to[v].size(); ++i) {
        int nv = to[v][i];
        if (timestamp[nv][0] > 0) continue;
        dfs(nv, t);
    }
    timestamp[v][1] = t++;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    cin >> n;
    to.resize(n);
    rep(i, n) {
        int u, k;
        cin >> u >> k;
        u--;
        rep(j, k) {
            int v;
            cin >> v;
            v--;
            to[u].push_back(v);
        }
    }

    timestamp.resize(n, vector<int>(2, 0));
    int t = 1;
    rep(i, n) {
        if (timestamp[i][0] == 0) dfs(i, t);
    }

    rep(i, n) {
        cout << i+1 << " " << timestamp[i][0] << " " << timestamp[i][1] << endl;
    }
}