Go: package main

/*
深さ優先探索
*/

import (
	"bufio"
	"fmt"
	"log"
	"os"
	"strconv"
	"strings"
)

func main() {
	scanner := makeScanner(8192)
	n := eGetInt(scanner)
	g := make([][]int, n+1)
	for i := 1; i < n+1; i++ {
		ints := eGetInts(scanner)
		num, vcount := ints[0], ints[1]
		g[i] = make([]int, vcount)
		for j := 0; j < vcount; j++ {
			g[num][j] = ints[j+2]
		}
	}
	hist := make([]struct{ d, f int }, n+1)
	t := 0
	var visit func(int)
	visit = func(num int) {
		if hist[num].d == 0 {
			stack := []int{}
			t++
			hist[num].d = t
			stack = append(stack, num)
			for len(stack) > 0 {
				// トップを訪問する
				top := stack[len(stack)-1]
				for i := 0; i < len(g[top]); i++ {
					if hist[g[top][i]].d == 0 {
						t++
						hist[g[top][i]].d = t
						stack = append(stack, g[top][i])
						goto endloop
					}
				}
				// 訪問場所がなくなったら
				// pop
				stack = stack[0 : len(stack)-1]
				t++
				hist[top].f = t
			endloop:
			}
		}
	}
	for i := 1; i < n+1; i++ {
		visit(i)
	}
	for i := 1; i < n+1; i++ {
		fmt.Println(i, hist[i].d, hist[i].f)
	}
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetInt64(r *bufio.Scanner) int64 {
	line := eGetLine(r)
	return eAtoInt64(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetInt64s(r *bufio.Scanner) []int64 {
	fields := eGetFields(r)
	ints := make([]int64, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoInt64(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}
func eAtoInt64(s string) int64 {
	n, err := strconv.ParseInt(s, 10, 64)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

C++: #include <bits/stdc++.h>
#define INF 100000000000
#define ll long long
#define pll pair<ll, ll>
using namespace std;

int main()
{
  ll N;
  cin >> N;
  vector<vector<ll>> connect(N);
  for (ll i = 0; i < N; ++i) {
    ll u, k;
    cin >> u >> k;
    for (ll j = 0; j < k; ++j) {
      ll v;
      cin >> v;
      connect.at(u - 1).push_back(v - 1);
    }
  }
  // for (ll i = 0; i < N; ++i) {
  //   sort(connect.at(i).begin(), connect.at(i).end());
  //   reverse(connect.at(i).begin(), connect.at(i).end());
  // }
  stack<ll> s;
  s.push(0);
  vector<bool> already(N, false);
  vector<pll> ans(N);
  already.at(0) = true;
  ans.at(0).first = 1;
  ll cnt = 2;
  while (!s.empty()) {
    ll check = s.top();
    bool tip = true;
    for (ll i = 0; i < connect.at(check).size(); ++i) {
      if (already.at(connect.at(check).at(i))) {
        continue;
      }
      already.at(connect.at(check).at(i)) = true;
      tip = false;
      s.push(connect.at(check).at(i));
      ans.at(connect.at(check).at(i)).first = cnt;
      cnt += 1;
      break;
    }
    if (tip) {
      ans.at(check).second = cnt;
      s.pop();
      cnt += 1;
    }
    if (s.empty()) {
      for (ll i = 0; i < N; ++i) {
        if (!already.at(i)) {
          already.at(i) = true;
          s.push(i);
          ans.at(i).first = cnt;
          cnt += 1;
          break;
        }
      }
    }
  }
  for (ll i = 0; i < N; ++i) {
    cout << i + 1 << ' ' << ans.at(i).first << ' ' << ans.at(i).second << endl;
  }
}

C++: #include <iostream>
#include <cstdio>
#define MAX 101
using namespace std;

int n;
int t=1;
int a[MAX][MAX]={};
int d[MAX]={},f[MAX]={};

void track(int p){
  if(d[p]==0){
    d[p]=t;
    t++;
  }
  for(int i=1;i<=n;i++){
    if(a[p][i]==1&&d[i]==0){
      track(i);
    }
  }
  f[p]=t; t++;
}

int main(){

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

  for(int i=1;i<=n;i++){
    if(d[i]==0) track(i);
  }

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

C++: #include<bits/stdc++.h>
//cout<<setprecision(1)<<fixed<<endl;
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
const int MAX_N=100000;
const int INF = 0x3f3f3f3f;
#define eps 1e-7
//#define Kongxiangzhouye
int n;
int a[123][123];
int st[123];
int ed[123];
int now;
void dfs(int local){
	st[local]=now++;
	for(int i=1;i<=n;i++){
		if(a[local][i]){
			if(st[i]==0){
				dfs(i);
			}
		}
	}
	ed[local]=now++;
}
int main(){
	ios::sync_with_stdio(false);
	while(cin>>n){
		memset(a,0,sizeof(a));
		memset(st,0,sizeof(st));
		memset(ed,0,sizeof(ed));
		for(int i=0;i<n;i++){
			int t,m;
			cin>>t>>m;
			for(int i=0;i<m;i++){
				int te;
				cin>>te;
				a[t][te]=1;
			}
			now=1;
		}
		for(int i=1;i<=n;i++){
			if(!st[i])
				dfs(i);
		}
		for(int i=1;i<=n;i++){
			cout<<i<<" "<<st[i]<<" "<<ed[i]<<endl;
		}
	}
	return 0;
}

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

int visit[100],end[100],a[100][100];
int t,N,u,k,col;

void rist_to_mat(int N) {
	for(int l=0; l<N; ++l) {
		cin >> u >> k;
		for (int i=0; i<k; ++i) {
			cin >> col;
			a[u-1][col-1] = 1;
		}
	}
}

void dfs(int cur,int N) {
	t += 1;
	visit[cur] = t;
	for(int dst=0; dst<N; ++dst) {
		if(a[cur][dst] == 1 && visit[dst] == 0) {
			dfs(dst,N);
		}
	}
	t += 1;
	end[cur] = t;
}

int main() {
	cin >> N;
	rist_to_mat(N);
	for(int i=0; i<N; ++i) {
		if(visit[i] == 0) dfs(i,N);
	}
	for(int i=0; i<N; ++i) {
		cout << i+1 << ' ' << visit[i] << ' ' << end[i] << endl;
	}
}

C++: #define _CRT_SECURE_NO_WARNINGS
#include<cstdio>

bool table[102][102] = {};
int color[102] = {}; //0:?????¢?´¢???1:?¨??????????, 2:??¢?´¢??????
int n, counter = 0;
int t_visit[102] = {};
int t_finish[102] = {};

void DFS(int y) {
	
	for (int j = 0; j <= n - 1;j++) {

		//?¨????or??¢?´¢???????????£???????????????
		if ((table[y][j] == 1)&&(color[j] == 0)) {
			color[y] = 1; //?¨???????????????????
			if (t_visit[y] == 0) t_visit[y] = ++counter;
			DFS(j);
		}

	}

	color[y] = 2; //??¢?´¢???????????????
	if (t_visit[y] == 0) t_visit[y] = ++counter;
	if (t_finish[y] == 0) t_finish[y] = ++counter;
	
}

int main(void) {
	int u, k, s;

	scanf("%d", &n);

	for (int i = 0;i <= n - 1;i++) {
		scanf("%d %d", &u, &k);
		for (int j = 0;j <= k - 1;j++) {
			scanf("%d", &s);
			table[u - 1][s - 1] = 1;
		}
	}


	for (int i = 0;i <= n - 1;i++) {
		if (color[i] == 0) {
			DFS(i);
		}
	}


	for (int i = 0; i <= n - 1;i++) {
		printf("%d %d %d\n", i + 1, t_visit[i], t_finish[i]);
	}

	return 0;
}