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 <string>
#include <sstream>
#include <vector>
#include <map>
#include <stack>
#include <queue>
#include <deque>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <climits>
#include <cstring>


using namespace std;

const int N_MAX = 1000000;
/*
bool update_num_to_visit(int st, int en, int* arr){
  if(st==-1) return false;
  arr[st]--;
  return arr[st]==0;
  }*/

int main(){
  int n;
  cin >> n;
  stack<pair<int, int> > edges;
  stack<pair<int, int> > paths;
  
  int** adjl = new int*[n];
  int* d = new int[n];
  int* f = new int[n];
  
  for(int i=0; i<n; i++){
    adjl[i] = new int[n];
    memset(adjl[i], -1, n * sizeof(adjl[i][0]));
  }
  
  memset(d, -1, n*sizeof(d[0]));
  memset(f, -1, n*sizeof(f[0]));

  for(int i=0; i<n; i++){
    int row_num, k;
    cin >> row_num >> k; row_num--;
    
    for(int j=0; j<k; j++){
      int node_num;
      cin >> node_num; node_num--;
      adjl[row_num][j] = node_num; // [[3, 5, -1 , ...], [1, 3, -1, ...], [1, 2], ...]
    }
  }

  for(int row_num=n-1; row_num>=0; row_num--){
      pair<int, int> p;
      p.first = -1; p.second = row_num; // visited from nowhere
      edges.push(p);
    }

  int time = 1;
  while(!edges.empty()){
    //    cout << "time: " << time << endl;
    
    pair<int, int> edge;
    edge = edges.top(); edges.pop();
    int st, en; st = edge.first; en = edge.second;
    //    cout << "visiting: " << en << " from: " << st << endl;
    
    pair<int, int> path; 
    // record path to go back
    if(st > -1){ // exclude (-1, node)
      path.first = en; path.second = st;
      // avoid inf loop: if the node is not finished, have to go back at some point
      if(f[path.second] == -1){
	paths.push(path);
	// cout << "<" << path.first << ", " << path.second << "> pushed as a path." << endl;
      }
    }    
    
    // if first time visit, mark as visited
    if(d[en] == -1) d[en] = time;
    
    // if not first time, check if it was finished.
    // if it was already finished, continue
    if(f[en] != -1){
      continue;
    }
    
    // counter for opened nodes
    int unvisited_node_num = 0;

    // open node (reverse order)
    for(int i=n-1; i>=0; i--){
      int next_node = adjl[en][i];
      // cout << "next_node: " << next_node << endl;
      // undefined dest or visited, continue
      if(next_node == -1) continue;
      if(d[next_node] != -1){
	// if num_to_visit[en] > 0;
	continue;
      }
      // if unvisited, push into stack
      unvisited_node_num++;
      pair<int, int> next_edge; next_edge.first = en; next_edge.second = next_node;
      edges.push(next_edge);
      // cout << "<" << next_edge.first << ", " << next_edge.second << "> pushed." << endl;
    }

    // if there are no unvisited linked nodes anymore, mark the node finished
    if(unvisited_node_num == 0){
      // cout << "going back..." << endl;
      f[en] = time + 1;
      // cout << "f[" << en << "]: " << f[en] << endl;
      
      // way to go back
      if(paths.empty()) break;
      path = paths.top(); paths.pop();
      edges.push(path);
      // cout << "path pushed." << endl;
    }
    time++;
  }

  // print 'i+1, d[i], f[i]'
  
  for(int i=0; i<n; i++){
    cout << i+1 << " " << d[i] << " " << f[i] << endl;
  }
  
  for(int i=0; i<n; i++){
    delete[] adjl[i];
  }
  delete[] adjl;
  delete[] d;
  delete[] f;
  
  return 0;
}

C++: #include<iostream>
using namespace std;
#define MAX 100

int mat[MAX][MAX] = {};
int n, time = 0, d[MAX] = {}, f[MAX] = {};
bool c[MAX];

void dfs_visit(int u){
    c[u] = true;
    d[u] = ++time;
    for(int i = 0; i < n; i++){
        if(mat[u][i] == 0)  continue;
        if(!c[i])   dfs_visit(i);
    }
    f[u] = ++time;
}

void dfs(){
    for(int i = 0; i < n; i++){
        if(!c[i])   dfs_visit(i);
    }

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

int main(){
    cin >> n;
    
    for(int i = 0; i < n; i++){
        int x, k, y;
        cin >> x >> k;
        while(k-- > 0){
            cin >> y;
            mat[x-1][y-1] = 1;
        }
    }

    dfs();
    return 0;
}

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

int n;
int a[100][100] = {0};
int k[100] = {0};
int t = 1;
int d[100] = {0};
int f[100] = {0};

int kansu( int i ){
	if ( d[i] != 0 ) return 0;
	d[i] = t;
	t++;
	for ( int j = 0; j < k[i]; j++ ) {
		if ( kansu( a[i][j] ) == 1 ) t++;
	}
	f[i] = t;
	return 1;
}

int main(){
	cin >> n;
	int s;
	for ( int i = 0; i < n; i++ ) {
		cin >> s;
		cin >> k[i];
		for ( int j = 0; j < k[i]; j++ ) {
			cin >> s;
			a[i][j] = s-1;
		}
	}
	kansu (0);
	for ( int i = 0; i < n; i++ ) {
		cout << i+1 << " " << d[i] << " " << f[i] << endl;
	}
	return 0;
}