Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve

const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 最初にiを訪問した時刻。発見時刻
//f[i]: iの隣接リストを訪問し終えた時刻。完了時刻
var color, d, f [MAX]int

func dfs_visit(u int) {
	color[u] = GRAY
	time++
	d[u] = time
	//隣接を調べる
	for v := 0; v < n; v++ {
		if M[u][v] == 0 {
			continue
		}
		//隣接するvが、未訪問だった場合
		if color[v] == WHITE {
			dfs_visit(v)
		}
	}
	//訪問完了処理
	color[u] = BLACK
	time++
	f[u] = time
	//訪問完了
}

func dfs() {
	//初期化
	for u := 0; u < n; u++ {
		color[u] = WHITE
	}
	time = 0

	//未訪問のuを始点として、深さ優先探索
	for u := 0; u < n; u++ {

		if color[u] == WHITE {
			dfs_visit(u)
		}
	}

	for u := 0; u < n; u++ {
		fmt.Println(u+1, d[u], f[u])
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	dfs()

}

C++: #include <iostream>
#include <cstdio>
using namespace std;
static const int N=100,WHITE=0,GRAY=1,BLACK=2;

int n,M[N][N];
int color[N],d[N],f[N],tt;

void dfs_visit(int u) {
  int v;
  color[u]=GRAY;
  d[u]=++tt;
  for (v=0; v<n; v++) {
    if (M[u][v]==0) {
      continue;
    }
    if(color[v]==WHITE) {
      dfs_visit(v);
    }
  }
  color[u]=BLACK;
  f[u]=++tt;
}
void dfs() {
  int u;
  for (u=0; u<n; u++) {
    color[u]=WHITE;
  }
  tt=0;
  for (u=0; u<n; u++) {
    if (color[u]==WHITE) {
      dfs_visit(u);
    }
  }
  for (u=0; u<n; u++) {
    cout<<u+1<<" "<<d[u]<<" "<<f[u]<<endl;
  }
}
int main() {
  int u,v,k,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<string>
#include<vector>
#include<algorithm>
#include<tuple>
#include<map>
#include<queue>
#include<set>
#include<stack>
#include<deque>
#include<cmath>
#include<stack>
#define rep(i,n) for(int i = 0;i<n;i++)
#define _GLIBCXX_DEBUG
using ll = long long; 
using namespace std;

const int N = 100;
const int WHITE = 0;
const int GRAY = 1;
const int BLACK = 2;
int n,M[N][N];
int color[N],d[N],f[N],tt;

void dfs_visit(int u) {
    int v;
    color[u] = GRAY;
    d[u] = GRAY;
    d[u] = ++tt;
    for(v = 0; v < n;v++) {
        if(M[u][v] == 0) continue;
        if(color[v] == WHITE) {
            dfs_visit(v);
        }
    }
    color[u] = BLACK;
    f[u] = ++tt;
}
void dfs() {
    int u;
    for(u = 0;u < n;u++) {
        color[u] = WHITE;
    }
    tt = 0;
    for(u = 0;u < n;u++) {
        if(color[u] == WHITE) dfs_visit(u);
    }
    for(u = 0;u < n;u++) {
        cout << u+1 <<" " <<d[u] << " " << f[u] << endl;
    }
}

int main() {
    int u,v,k,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++: #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;
		}
	}

	DFS(0);

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

	return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (ll i = 0; i < (ll)n; i++)
#define PI 3.14159265358979323846
#define vll vector<long long>
#define vvll vector<vector<long long>>
using namespace std;
using ll = long long;
using ld = long double;

// ----本問について----
// 問題：Depth First Search
// 問題文URL：https://onlinejudge.u-aizu.ac.jp/problems/ALDS1_11_B
// 所要時間：
// 学んだこと：
// ------------------

// ----ここから本問のソースコード----
static const ll N_MAX = 110;

// グローバル変数（入力）
ll n, t, A[N_MAX][N_MAX], d[N_MAX], f[N_MAX], state[N_MAX];

// 入力
void input() { cin >> n; }

// 深さ優先探索
void dfs(ll u) {
  d[u] = ++t;
  state[u] = 1; // 発見
  rep(i, n) {
    ll v = i + 1;
    if (A[u][v] == 1 && state[v] == 0) { // 辺が存在かつ未発見なら
      dfs(v);
    }
  }
  f[u] = ++t;
  state[u] = 2; // 完了
}

void solve() {
  // 隣接リストを隣接行列に変換して二次元配列Aに格納
  rep(i, n) {
    ll v, k;
    cin >> v >> k;
    rep(j, k) {
      ll v2;
      cin >> v2;
      A[v][v2] = 1;
    }
  }

  t = 0;
  rep(i,n){
    if (state[i+1]==0){
      dfs(i+1);
    }
  }

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

int main() {
  input();
  solve();
  return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <math.h>
#include <complex>
#include <queue>
#include <deque>
#include <stack>
#include <map>
#include <unordered_map>
#include <set>
#include <bitset>
#include <functional>
#include <assert.h>
using ll=long long;
#define int ll
#define rng(i,a,b) for(int i=int(a);i<int(b);i++)
#define rep(i,b) rng(i,0,b)
#define gnr(i,a,b) for(int i=int(b)-1;i>=int(a);i--)
#define per(i,b) gnr(i,0,b)
#define eb emplace_back
#define all(x) x.begin(),x.end()
#define SZ(x) ((int)x.size())
#define fi first
#define se second
const int INF = 1e15;
using namespace std;

template<class T> using vc=vector<T>;
template<class T> using vvc=vc<vc<T>>;

using pi=pair<int,int>;
using vi=vc<int>;

template<class T>
inline bool chmax(T &a,T b){if(a<b){a=b;return true;}return false;}
template<class T>
inline bool chmin(T &a,T b){if(a>b){a=b;return true;}return false;}

vi G[200];
int cnt=1;
int s[200],f[200];
void dfs(int v){
    s[v]=cnt++;
    rep(k,SZ(G[v])){
        if(s[G[v][k]]) continue;
        dfs(G[v][k]);
    }
    f[v]=cnt++;
}
signed main() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout<<fixed<<setprecision(20);

    int N; cin >> N;
    rep(i,N){
        int a,n; cin >> a >> n;
        a--;
        rep(j,n){
            int b; cin >> b;
            b--;
            G[a].eb(b);
        }
    }
    rep(i,N){
        if(!s[i]) dfs(i);
    }
    rep(i,N){
        cout << i+1 << " " << s[i] << " " << f[i] << "\n";
    }
}