Go: package main

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

func main() {
	scn := bufio.NewScanner(os.Stdin)
	scn.Split(bufio.ScanWords)
	nextInt := func() int { scn.Scan(); r, _ := strconv.Atoi(scn.Text()); return r }
	w := bufio.NewWriter(os.Stdout)

	n := nextInt()
	vecs := make([][]int, n)
	for i := 0; i < n; i++ {
		u := nextInt()
		k := nextInt()
		for j := 0; j < k; j++ {
			vecs[u-1] = append(vecs[u-1], nextInt()-1)
		}
	}

	ds := make([]int, n)
	fs := make([]int, n)
	founds := make([]bool, n)
	t := 0
	for i := range founds {
		if !founds[i] {
			t = dfs(vecs, ds, fs, founds, i, t)
		}
	}

	for i := 0; i < n; i++ {
		fmt.Fprintln(w, i+1, ds[i], fs[i])
	}

	w.Flush()
}

func dfs(vecs [][]int, ds, fs []int, founds []bool, i, t int) (time int) {
	t++
	ds[i] = t
	founds[i] = true
	for _, v := range vecs[i] {
		if !founds[v] {
			t = dfs(vecs, ds, fs, founds, v, t)
		}
	}
	t++
	fs[i] = t

	return t
}

C++: #include <iostream>
#include <cmath>
#include <set>
#include <string>
#include <algorithm>
#include <vector>
#include <bitset>
#include <iomanip>
#include <map>

using std::cin;
using std::cout;
using std::endl;
using std::string;
using std::vector;
using std::bitset;

#define rep(i,n)    for(int i=0; i<(int)n; i++)
typedef long double ld;
typedef long long ll;
typedef vector<int> vint;
typedef vector<ll> vll;
typedef std::pair<int, int> pii;
typedef std::pair<ll, ll> pll;

void printFixedDouble(double d, int fix) {
    cout << std::fixed;
    cout << std::setprecision(fix) << d << endl;
}

int timestamp = 1;

void search(int index, vector<vector<int> > &graph, vector<int> &dest, vector<int> &fin) {
    if (dest[index - 1] != -1) return;
    dest[index - 1] = timestamp;
    timestamp++;
    for (int& dsts: graph[index - 1]) {
        search(dsts, graph, dest, fin);
    }
    fin[index - 1] = timestamp;
    timestamp++;
}

int main() {
    int n;
    cin >> n;
    vector<vector<int> > graph(n, vector<int>());

    rep(i, n) {
        int index, k;
        cin >> index >> k;
        rep(j, k) {
            int dst;
            cin >> dst;
            graph[index - 1].push_back(dst);
        }
    }

    
    vector<int> dest(n, -1);
    vector<int> fin(n, -1);

    rep(i, n) {
        search(i + 1, graph, dest, fin);
    }

    rep(i, n) {
        cout << i+1 << " " << dest[i] << " " << fin[i] << endl;
    }
}

C++: #include <iostream>
#include "memory.h"
#include <stack>

using namespace std;

bool matrix[100][100];
int n;

int next(int k){
	for(int i = 0; i < n; i++){
		if(matrix[k][i] == true)
			return i + 1;
	}
	return false;
}

int main(){
	int index, temp, num, current, count = 1;
	int start_end[100][2];
	stack<int> back;

	memset(matrix, 0, sizeof(matrix));
	memset(start_end, 0, sizeof(start_end));

	cin >> n;

	for(int i = 0; i < n; i++){
		cin >> index >> num;
		while(num--){
			cin >> temp;
			matrix[index-1][temp-1] = true;
		}
	}
	back.push(0);
	current = 0;
	while(!back.empty()){
		int r;
		r = next(current);
		if(start_end[current][0] == 0){
			start_end[current][0] = count;
			count++;
		}
		if(r){
			matrix[current][r-1] = false;
			back.push(current);
			current = r - 1;
		}
		else{
			if(start_end[current][1] == 0){
				start_end[current][1] = count;
				count++;
			}
			current = back.top();
			back.pop();
		}
		
	}
	for(int i = 0; i < n; i++){
		cout << i + 1 << " " << start_end[i][0] << " " << start_end[i][1] << endl;
	}


}

C++: #include<iostream>
#include<stack>
using namespace std;
#define White 0
#define Black 1
#define Red 2
#define MAX 100
struct Queue {
	int color, d, f, relate[MAX], roots, id;
};
Queue Q[MAX];
stack<int> q;
stack<int> dmax;
int search(int deep) {
	while (!q.empty()) {
		int s = q.top();
		int whitecount = 0;
		for (int i = 0; i < Q[s - 1].roots; i++) {
			int nakami = Q[s - 1].relate[i];
			if (Q[nakami - 1].color == White) {
				whitecount += 1;
				deep += 1;
				Q[nakami - 1].color = Black;
				q.push(Q[nakami - 1].id);
				Q[nakami - 1].d = deep;
				search(deep);
			}
		}
		if (whitecount == 0) {
			deep += 1;
			Q[s - 1].f = deep;
			dmax.push(deep);
			Q[s - 1].color = Red;
			q.pop();
			search(deep);
		}
	}
	return dmax.top();
}
int main() {
	int n, u, k, v;
	cin >> n;
	for (int i = 0; i < n; i++) {
		Q[i].color = White;
	}
	for (int i = 0; i < n; i++) {
		cin >> u >> k;
		Q[u - 1].id = u;
		Q[u - 1].roots = k;
		if (i == 0) {
			Q[u - 1].d = 1;
			Q[u - 1].color = Black;
			q.push(u);
		}
		if (k != 0) {
			for (int i = 0; i < k; i++) {
				cin >> v;
				Q[u - 1].relate[i] = v;
			}
		}
	}
	int max = search(1);
	for (int i = 0; i < n; i++) {
		if (Q[i].color == White) {
			Q[i].d = max + 1;
			q.push(Q[i].id);
			search(max+1);
			max = search(max);
		}
	}
	for (int i = 0; i < n; i++) {
		cout << Q[i].id << " " << Q[i].d << " " << Q[i].f << endl;
	}

}

C++: #include<stdio.h>
#define N 100
#define WHITE 0 // ????¨??????????????????????????????°
#define GRAY 1 // ??¢?´¢?????????????????????????????°
#define BLACK 2 // ??¢?´¢????????????????????????????????°

int n,/* ????????° */ M[N][N]; /* ??£??\?????? */
int color[N],/* ??????i????¨??????¶??? */ d[N],/* ??????i?????????????¨?????????????????????? */ f[N],/* ??????i?????£??\??????????????????????????????????????? */ 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; // ??????u????????????v????????????????????¨?????????
		if(color[v] == WHITE){
			dfs_visit(v); // ??????v????¨???????????????¨??????????????°???v??????????????¢?´¢???????§???????
		}
	}
	color[u] = BLACK; // ??¢?´¢??????????????????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++){
		// ????¨???????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; // u:??????????????? k:u???????¬???° v:??£??\?????????????????????

	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;
}

C++: #include <iostream>

using namespace std;

typedef pair<int, int> p;

int n,u,k,t;
int** v;
p* T;

void bfs(int pos) {
  // if visited
  if (T[pos].first) {
    return;
  }
  // check visit
  T[pos].first = ++t;

  int leng = v[pos][0];
  for (int i = 1; i <= leng; i++) {
    bfs(v[pos][i]);
  }
  T[pos].second = ++t;
}

int main() {
  cin >> n;

  v = new int*[n+1];
  for (int i = 0; i < n; i++) {
    cin >> u >> k;
    v[u] = new int[k+1];
    v[u][0] = k;
    for (int j = 1; j <= k; j++) {
       cin >> v[u][j];
    }
  }

  T = new p[n+1];
  for (int i = 1; i <= n; i++) {
    T[i] = p(0, 0);
  }

  t = 0;
  for (int i = 1; i <= n; i++) {
    bfs(i);
  }

  for (int i = 1; i <= n; i++) {
    cout << i << " " << T[i].first << " " << T[i].second << endl;
  }
  
  return 0;
}