Go: package main

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

type TimeRecord struct {
	discoverTime int
	finishTime   int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	timeRecordMap := make([]TimeRecord, n)
	childrenMap := make([][]int, n)
	for i := 1; i <= n; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		timeRecordMap[node-1] = TimeRecord{-1, -1}

		childNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		childrenMap[node-1] = make([]int, childNum)
		for j := 0; j < childNum; j++ {
			child, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			childrenMap[node-1][j] = child
		}
	}

	timer := 1
	for {
		startNode := findStartNode(childrenMap, timeRecordMap)
		if startNode > 0 {
			visit(startNode, &timer, childrenMap, timeRecordMap)
		} else {
			break
		}
	}
	for k, v := range timeRecordMap {
		fmt.Printf("%d %d %d\n", k+1, v.discoverTime, v.finishTime)
	}
}

func findStartNode(childrenMap [][]int, timeRecordMap []TimeRecord) int {
	x := -1
	for node, timeRecord := range timeRecordMap {
		if timeRecord.discoverTime < 0 {
			x = node + 1
			break
		}
	}
	if x < 0 {
		return -1
	}

	found := false
	i := 0
	for i < len(childrenMap) {
		children := childrenMap[i]
		for j := 0; j < len(children); j++ {
			if children[j] == x {
				x = j + 1
				found = true
				break
			}
		}
		if found {
			i = 0
		} else {
			i++
		}
	}
	return x
}

func visit(currentNode int, timer *int, childrenMap [][]int, timeRecordMap []TimeRecord) {
	if timeRecordMap[currentNode-1].discoverTime > 0 {
		return
	}
	children := childrenMap[currentNode-1]
	timeRecordMap[currentNode-1] = TimeRecord{*timer, timeRecordMap[currentNode-1].finishTime}
	(*timer)++
	for i := 0; i < len(children); i++ {
		visit(children[i], timer, childrenMap, timeRecordMap)
	}
	timeRecordMap[currentNode-1] = TimeRecord{timeRecordMap[currentNode-1].discoverTime, *timer}
	(*timer)++
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: #include <iostream>
#include <stack>
#define N 100
#define WHITE 0
#define GRAY  1
#define BLACK 2
#define NIL -1

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

// uの隣接点を番号順に取得する
// nt[N]には番号順での探索開始位置を保存する
// 隣接点がなければ-1を返す
int next(int u)
{
	for (int v = nt[u]; v < n; v++)
	{
		nt[u]++;
		if (M[u][v]) return v;
	}
	return NIL;
}

// rを開始地点として深さ優先探索を行う
void dfs_visit(int r)
{
	std::stack<int> S;
	S.push(r);
	color[r] = GRAY;
	d[r] = tt++;

	while (!S.empty())
	{
		int u = S.top();
		int v = next(u);
		if (v != NIL)
		{
			if (color[v] == WHITE)
			{
				S.push(v);
				color[v] = GRAY;
				d[v] = tt++;
			}
		}
		else
		{
			S.pop();
			color[u] = BLACK;
			f[u] = tt++;
		}
	}
}

//初期化処理、探索、結果出力を行う
void dfs()
{
	for (int i = 0; i < n; i++)
	{
		color[i] = WHITE;
		nt[i] = 0;
	}
	tt = 1;

	for (int i = 0; i < n; i++)
	{
		if (color[i] == WHITE) dfs_visit(i);
	}

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

int main()
{
	std::cin >> n;
	for (int i = 0; i < n; i++)
	{
		for (int j = 0; j < n; j++)
		{
			M[i][j] = 0;
		}
	}

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

	dfs();
}

C++: #include <iostream>
#include <stack>
using namespace std;
const int MAX_N = 100;

int A[MAX_N+1][MAX_N+1];
pair<int, int> TIMESTAMPS[MAX_N+1];
int N;

void solve() {
  int ts = 0;
  stack<int> S;

  for (int i = N; i > 0; i--) {
    if (TIMESTAMPS[i].first == 0) S.push(i);
  }

  while (!S.empty()) {
    int c = S.top();

    if (TIMESTAMPS[c].first == 0)
      TIMESTAMPS[c].first = ++ts;

    for (int i = N; i > 0; i--) {
      if (A[c][i] == 1 && TIMESTAMPS[i].second == 0)
        S.push(i);
    }

    if (S.top() == c) {
      if (TIMESTAMPS[c].second == 0)
        TIMESTAMPS[c].second = ++ts;
      S.pop();
    }
  }
}

int main() {
  cin >> N;

  for (int i = 1; i <= N; i++) {
    for (int j = 1; j <= N; j++) {
      A[i][j] = 0;

    }
    TIMESTAMPS[i] = make_pair(0, 0);
  }

  for (int i = 0; i < N; i++) {
    int u, k; cin >> u >> k;
    for (int j = 0; j < k; j++) {
      int t; cin >> t;
      A[u][t] = 1;
    }
  }

  solve();

  for (int i = 1; i <= N; i++) {
    cout << i << ' '
         << TIMESTAMPS[i].first << ' '
         << TIMESTAMPS[i].second << endl;
  }

  return 0;
}

C++: #include <iostream>
 
using namespace std;
 
    int TIME = 0;
    int d[101];
    int f[101];
    int num;
    int graph[101][101] = {0};
 
void dfs(int x){
    TIME++;
    d[x] = TIME;
 
    for(int i=1;i<=num;i++){
        if(graph[x][i] == 1 && d[i]==0){
            dfs(i);
        }
    }
    f[x] = ++TIME;
}
 
int main(){
    int hon;
    int eda;
    int ver;
 
    cin>>num;
    for(int i=0;i<num;i++){
        cin>>eda;
        cin>>hon;
        for(int j=0;j<hon;j++){
            cin>>ver;
            graph[eda][ver]++;
        }
    }
     
    for(int i=1;i<=num;i++){
        if(d[i]==0)
            dfs(i);
    }
 
    for(int i=1;i<=num;i++){
        cout<<i<<" "<<d[i]<<" "<<f[i]<<endl;
    }
 
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
struct cww{cww(){ios::sync_with_stdio(false);cin.tie(0);}}star;
#define P(x) cout << (x) << endl
#define p(x) cout << (x)
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define vv(type, c, m, n, i) vector<vector<type>> c(m, vector<type>(n, i));
#define rep(i,a,n) for(int i=(a), i##_len=(n); i<i##_len; ++i)
#define rrep(i,a,n) for(int i=(a), i##_len=(n); i>i##_len; --i)
#define len(x) ((int)(x).size())
#define mp make_pair
#define eb emplace_back
typedef long long ll;
typedef vector<int> vi;
typedef vector<double> vd;
typedef vector<long long> vll;
typedef vector<string> vs;
typedef vector<bool> vb;
constexpr int MAX = 101;
enum Color { WHITE = 0, GRAY, BLACK};
int n, tt{0};
vv(int, M, MAX, MAX, 0);
vi color(MAX, 0), d(MAX, 0), f(MAX, 0);
inline void dfs_visit(int u) {
	color[u] = GRAY;
	d[u] = ++tt;
	rep(v, 0, n) {
		if(M[u][v] == 0) continue;
		if(color[v] == WHITE) {
			dfs_visit(v);
		}
	}
	color[u] = BLACK;
	f[u] = ++tt;
}
inline void dfs() {
	rep(u, 0, n) {
		if(color[u] == WHITE) dfs_visit(u);
	}
	rep(u, 0, n) {
		cout << u + 1 << " " << d[u] << " " << f[u] << endl;
	}
}
int main() {
	cin >> n;
	int u, k, v;
	rep(i, 0, n) {
		cin >> u >> k;
		--u;
		rep(j, 0, k) {
			cin >> v;
			M[u][--v] = 1;
		}
	}
	dfs();
	return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <utility>
#include <queue>
#include <stack>
#include <string>
#include <climits>
using namespace std;

#define MAX_N 101

int n, t;
vector<vector<int> > A(MAX_N, vector<int>(MAX_N, 0));
stack<int> S;
int d[MAX_N] = {};
int f[MAX_N] = {};

void df(int e)
{
    d[e] = t++;
    for (int i = 1; i <= n; i++) {
        if (A[e][i] && !d[i]) df(i);
    }
    f[e] = t++;
}

int main()
{
    int i, u, k, v;
    cin >> n;
    for (i = 0; i <= n; i++) A[0][i]++;
    for (i = 1; i <= n; i++) {
        cin >> u >> k;
        while (k--) {
            cin >> v;
            A[u][v]++;
        }
    }
    t = 0;
    df(0);
    for (i = 1; i <= n; i++)
        cout << i << " " << d[i] << " " << f[i] << endl;
    return 0;
}