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 <iostream>
#include <vector>
using namespace std;

int n;
vector<vector<int> > A;
vector<vector<int> > T;
int t = 0;

void dfs(int cur){ // cur????¨????
    // cur ????¨??????????????¨????
    t += 1;
    T[cur][0] = t;
    // ???????¢??????¨??¨???
    // cerr << "visiting " << cur << " " << t << endl;

    for(int dst = 0; dst < n; ++dst){ // ??¨???????????? dst ????????????
        if(A[cur][dst] == 1 && T[dst][0] == -1){ // cur??????dst??????????????????,dst???????¨??????????
            dfs(dst);
        }
    }
    // cur ????¨????????????????????¨????
    t += 1;
    T[cur][1] = t;
    // ??¢??°?????????????????????????????? (?????¢??°)
    return; // ?????\???
}

int main(){
    cin >> n;
    A = vector<vector<int> >(n, vector<int>(n, 0));
    T = vector<vector<int> >(n, vector<int>(2, -1));
    for(int i=0; i<n; ++i){
        int k;
        cin >> k;
        // 1~n???index?????¨????????????????????????????????????1????????????0~n-1????????????
        k -= 1;
        int u;
        cin >> u;
        for(int j=0; j<u; ++j){
            int v;
            cin >> v;
            v -= 1;
            A[k][v] = 1;
        }
    }
    for(int i=0; i<n; ++i){
        if(T[i][0] == -1){
          dfs(i);
        }
    }
    for(int i=0; i<n; ++i){
        cout << i+1 << " " << T[i][0] << " " << T[i][1] << endl;
    }
}

C++: #include <cstdio>

typedef struct{
	bool isVisited;
	int degree;
	int start;
	int end;
	int *neighbors;
} node;

int count = 1;

void dfs(node* nodes, int id){
	nodes[id].isVisited = true;
	if (nodes[id].start == 0) nodes[id].start=count;
	for (int i=0; i<nodes[id].degree; i++){
		if (!nodes[nodes[id].neighbors[i]].isVisited){
			count ++;
			dfs(nodes, nodes[id].neighbors[i]);
		}
	}
	count++;
	nodes[id].end = count;
}

int main(){
	int n, d, r, id;
	node *nodes;

	scanf("%d", &n);
	nodes = new node[n];
	for (int i=0; i<n;i++){
		nodes[i].isVisited=false;
		scanf("%d %d", &r, &d);
		nodes[i].degree=d;
		nodes[i].neighbors = new int[d];
		nodes[i].start = 0;
		
		for (int j=0;j<d;j++){
			scanf("%d", &id);
			nodes[i].neighbors[j] = id-1;
		}
	}

	dfs(nodes, 0);
	for (int i=0; i<n;i++){
		printf("%d %d %d\n", i, nodes[i].start, nodes[i].end);
		delete []nodes[i].neighbors;
	}
	delete []nodes;
	return 0;
}

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

using namespace std;

/*****************************************/
/*         Function prototype            */
/*****************************************/

vector<vector<int> > list_to_mat(vector<vector<int> >& adj);
void dump_mat( vector<vector<int> >& mat);
void dfs(vector<vector<int> >& adj_list, int now, vector<int>& d, vector<int>& f, int *t);

/*****************************************/
/*            Main Function              */
/*****************************************/


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

  vector<vector<int> > list(n+1);
  for(int i=0; i<n; i++){
    int u,k; cin >> u >> k;
    vector<int> tmp(k);
    for(int j=0; j<k; j++) cin >> tmp[j];
    sort(tmp.begin(),tmp.end());
    list[u] = tmp;
  }
  int t=1;
  vector<int> d(n+1,-1);
  vector<int> f(n+1,-1);

  dfs(list,1,d,f,&t);

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



/*****************************************/
/*            Implimentation             */
/*****************************************/


void dfs(vector<vector<int> >& adj_list, int now, vector<int>& d, vector<int>& f, int* t){
  d[now] = *t;
  (*t)++;
  
  for(auto v : adj_list[now]){
    if(d[v] != -1) continue;
    dfs(adj_list, v, d, f, t);
  }
  f[now] = *t;
  (*t)++;
  return ;
}


vector<vector<int> > list_to_mat(vector<vector<int> >& adj){
  const int mat_size = (int)adj.size();
  vector<vector<int> > ans(mat_size,vector<int>(mat_size,0));
  for(int i=0; i<mat_size; i++){
    for(int j=0; j<adj[i].size(); j++){
      ans[i][adj[i][j]-1] = 1;
    }
  }
  return ans;
}


void dump_mat( vector<vector<int> >& mat){
  
  const int mat_size = (int)mat.size();
  for(int i=0; i<mat_size; i++){
    for(int j=0; j<mat[i].size(); j++){
      cout << mat[i][j];
      if(j!=mat[i].size()-1)
	cout << " ";
      else
	cout << "\n";
    }
  }
}

C++: #include <stdio.h>
#define N 100
#define WHITE 0
#define GRAY 1
#define 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++) printf("%d %d %d\n", u + 1, d[u], f[u]);
}

int main(){
	int u, v, k, i, j;
	scanf("%d", &n);
	for (i = 0; i<n; i++)
		for (j = 0; j<n; j++)
			M[i][j] = 0;
	for (i = 0; i<n; i++){
		scanf("%d %d", &u, &k);
		u--;
		for (j = 0; j<k; j++){
			scanf("%d", &v);
			v--;
			M[u][v] = 1;
		}
	}
	dfs();
	return 0;
}