Go: package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
)

const N = 100

const (
	WHITE = iota
	GRAY
	BLACK
)

type Graph struct {
	M               [N][N]int
	color, d, f, nt [N]int
	tt              int
}

func (g *Graph) next(u, n int) int {
	for v := g.nt[u]; v < n; v++ {
		g.nt[u] = v + 1
		if g.M[u][v] != 0 {
			return v
		}
	}
	return -1
}

func (g *Graph) dfsVisit(r, n int) {
	var S []int
	S = append([]int{r}, S...)
	g.color[r] = GRAY
	g.tt++
	g.d[r] = g.tt

	for len(S) != 0 {
		u := S[0]
		v := g.next(u, n)
		if v == -1 {
			S = S[1:]
			g.color[u] = BLACK
			g.tt++
			g.f[u] = g.tt
			continue
		}

		if g.color[v] != WHITE {
			continue
		}

		g.color[v] = GRAY
		g.tt++
		g.d[v] = g.tt
		S = append([]int{v}, S...)
	}
}

func (g *Graph) dfs(n int) string {
	for i := 0; i < n; i++ {
		g.color[i] = WHITE
	}
	g.tt = 0

	for u := 0; u < n; u++ {
		if g.color[u] == WHITE {
			g.dfsVisit(u, n)
		}
	}

	var out bytes.Buffer
	for i := 0; i < n; i++ {
		out.WriteString(fmt.Sprintf("%d %d %d\n", i+1, g.d[i], g.f[i]))
	}

	return strings.TrimRight(out.String(), "\n")
}

func answer(reader io.Reader) string {
	sc := bufio.NewScanner(reader)
	sc.Split(bufio.ScanWords)

	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())

	var g Graph
	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())
		u--
		for j := 0; j < k; j++ {
			sc.Scan()
			v, _ := strconv.Atoi(sc.Text())
			v--
			g.M[u][v] = 1
		}
	}

	return g.dfs(n)
}

func main() {
	fmt.Println(answer(os.Stdin))
}

C++: #include <iostream>
#include <vector>
#include <vector>
#include <algorithm>
#include <stack>

using namespace std;

static const int N = 100;
int n, m[N][N];
int time, begT[N], endT[N];
bool visited[N];

int nxt(int u)
{
	for (int v = 0; v < n; ++v)
	{
		if (m[u][v] > 0 && !visited[v]) return v;
	}
	return -1;
}

void dfs_helper(int idx)
{
	stack<int> s;
	s.push(idx);
	begT[idx] = time++;
	visited[idx] = true;

	while (!s.empty())
	{
		int u = s.top();
		int v = nxt(u);
		if (-1 == v)
		{
			s.pop();
			endT[u] = time++;
			continue;
		}
		s.push(v);
		begT[v] = time++;
		visited[v] = true;
	}
}

void dfs()
{
	time = 1;

	for (int i = 0; i < n; ++i)
	{
		if (!visited[i]) dfs_helper(i);
	}

	for (int i = 0; i < n; ++i)
	{
		cout << i + 1 << " " << begT[i] << " " << endT[i] << endl;
	}
}

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

	for (int i = 0; i < n; ++i)
		visited[i] = false;

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

	dfs();

	return 0;
}

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

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

int G[101][101];
int color[101];
int n;
int d[101], f[101], t;

void search_loop(int i)
{
	int next;
	d[i] = ++t;
	color[i] = GRAY;

	for(next = 1; next <= n; next++){
		if(i == next && G[i][i] > 0) break;
		if(G[i][next] > 0 && color[next] != BLACK){
			search_loop(next);
		}
	}
	f[i] = ++t;
	color[i] = BLACK;

	return;
}

void dfs()
{
	int i;
	for(i = 1; i <= n; i++) color[i] = WHITE;  // initialize.

	t = 0;
	for(i = 1; i <= n; i++){
		if(color[i] == WHITE) search_loop(i);
	}
	for(i = 1; i <= n; i++){
		cout << i << " " << d[i] << " " << f[i] << endl;
	}
	return ;
}

int main()
{
	int i, j, k, e;
	cin >> n;
	for(i = 1; i <= n; i++){
		for(j = 1; j <= n; j++){
			G[i][j] = 0;
		}
	}
	do{
		cin >> i >> e;
		for(j = 1; j <= e; j++){
			cin >> k;
			G[i][k] = 1;
		}
	}while(i < n);

	dfs();

	return 0;
}

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

using namespace std;

int main() {
  int n;
  cin >> n;

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

    for (int i = 0; i < k; i++) {
      int v;
      cin >> v;
      --v;

      adjacent[u].push_back(v);
    }
  }

  vector<int> d(n, 0), f(n, 0);
  vector<bool> visited(n, false);
  stack<int> S;

  S.push(0);

  int t = 1;

  d[0] = t;

  while (!S.empty()) {
    ++t;

    int u = S.top();

    if (!visited[u]) {
      visited[u] = true;
    }

    bool done = true;
    for (int i = 0; i < adjacent[u].size(); i++) {
      int v = adjacent[u][i];

      if (!visited[v]) {
        done = false;
        d[v] = t;
        S.push(v);
        break;
      }
    }

    if (done) {
      f[u] = t;
      S.pop();
    }

    // スタックが空になった後、未訪問なノードがあればそれを始点として再度DFSする
    if (S.empty()) {
      for (int i = 0; i < n; i++) {
        if (!visited[i]) {
          ++t;
          S.push(i);
          d[i] = t;
          break;
        }
      }
    }
  }

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

  return 0;
}

/*
6
1 2 2 3
2 2 3 4
3 1 5
4 1 6
5 1 6
6 0
*/

C++: #include <cstdint>
#include <vector>

using namespace std;

#define GRAPH_SIZE 101
#define START_INDEX 1

enum color_t {
  WHITE,
  GRAY,
  BLACK,
};

static uint32_t t = 0;
static color_t state[GRAPH_SIZE];
static vector<uint32_t> graph[GRAPH_SIZE];

void depth_first_search(void (*visited)(uint32_t), void (*invested)(uint32_t))
{
  for (uint32_t i = START_INDEX; i < GRAPH_SIZE; i++) {
    state[i] = WHITE;
  }

  static vector<pair<uint32_t, vector<uint32_t>>> stack;

  stack.push_back(make_pair(START_INDEX, graph[START_INDEX]));
  state[START_INDEX] = GRAY;
  t++;
  visited(START_INDEX);

  while (!stack.empty()) {
    pair<uint32_t, vector<uint32_t>> top = stack.back();
    bool found = false;
    for (uint32_t i = 0; i < top.second.size(); i++) {
      uint32_t next = top.second[i];
      if (state[next] == WHITE) {
        found = true;
        state[next] = GRAY;
        t++;
        visited(next);
        stack.push_back(make_pair(next, graph[next]));
        break;
      }
    }

    if (!found) {
      stack.pop_back();
      t++;
      state[top.first] = BLACK;
      invested(top.first);
    }
  }
}

#include <iostream>

static uint32_t visited_time[GRAPH_SIZE];
static uint32_t invested_time[GRAPH_SIZE];

static void visited(uint32_t i)
{
  visited_time[i] = t;
}

static void invested(uint32_t i)
{
  invested_time[i] = t;
}

int32_t main(void)
{
  uint32_t num;
  cin >> num;

  for (uint32_t i = 0; i < num; i++) {
    uint32_t index, len;
    cin >> index >> len;
    for (uint32_t j = 0; j < len; j++) {
      uint32_t val;
      cin >> val;
      graph[index].push_back(val);
    }
  }

  depth_first_search(visited, invested);

  for (uint32_t i = START_INDEX; i < (START_INDEX + num); i++) {
    cout << i << " " << visited_time[i] << " " << invested_time[i] << endl;
  }

  return 0;
}

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

using namespace std;

#define MAX 110
int num;
int matrix[MAX][MAX];
int dst[MAX];

void input(){
    cin >> num;
    for(int i=0;i<MAX;i++){
        dst[i] = -1;
        for(int j=0;j<MAX;j++){
            matrix[i][j] = 0;
        }
    }
    for(int i=1;i<=num;i++){
        int v; cin >> v;
        int tmp; cin >>tmp;
        for(int j=0;j<tmp;j++){
            int vi; cin >> vi;
            matrix[v-1][vi-1] = 1;
        }
    }
}

void dfs(){
    stack<int> S;
    S.push(0);
    dst[0] = 0;
    while(!S.empty()){
        int cur = S.top();
        S.pop();
        if(dst[cur]==-1 || dst[cur]== 0){
            for(int i=0;i<num;i++){
                if(matrix[cur][i]==1){
                    S.push(i);
                    dst[i] = dst[cur] + 1;
                }
            }
        }
        else if(dst[S.top()]+1 < dst[cur]){
            for(int i=0;i<num;i++){
                if(matrix[cur][i]==1){
                    S.push(i);
                    dst[i] = dst[cur] + 1;
                }
            }
        }
    }
    for(int i=0;i<num;i++){
        cout << i+1 << " " <<  dst[i] << endl;
    }
}

int main(){
    input();
    dfs();
}