Go: package main

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

var N int
var A [][]int
var t int
var color, d, f []int

const (
	WHITE = iota
	GRAY
	BLACK
)

func dfsVisit(u int) {
	color[u] = GRAY
	t ++
	d[u] = t
	for v:=0; v<N; v++ {
		if A[u][v] == 0 {
			continue
		}
		if color[v] == WHITE {
			dfsVisit(v)
		}
	}
	color[u] = BLACK
	t++
	f[u] = t
}

func dfs() {
	for u:=0; u<N; u++ {
		if color[u] == WHITE {
			dfsVisit(u)
		}
	}
	for u:=0; u<N; u++{
		fmt.Printf("%d %d %d\n", u+1, d[u], f[u])
	}
}


func nextInt(scanner *bufio.Scanner) int {
	scanner.Scan()
	num, _ := strconv.Atoi(scanner.Text())
	return num
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	N = nextInt(scanner)
	color = make([]int, N)
	d = make([]int, N)
	f = make([]int, N)
	A = make([][]int, N)
	for i:=0; i<N; i++{
		A[i] = make([]int, N)
	}
	for i:=0; i<N; i++{
		index := nextInt(scanner) - 1
		cnt := nextInt(scanner)
		for j:=0; j<cnt; j++ {
			v := nextInt(scanner) - 1
			A[index][v] = 1
		}
	}
	dfs()
}

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

using namespace std;

vector<vector<int>> adjacent;
vector<pair<int, int>> ans;
vector<bool>checked;

//?????????is????????????
int dfs(int now,int time) {
	ans[now].first = time;
	checked[now] = true;
	for (int i = 0; i < adjacent[now].size(); i++) 
		if (!checked[adjacent[now][i]]) time = dfs(adjacent[now][i], time + 1);
	ans[now].second = time+1;
	return time + 1;
}

int main() {
	int n,u,k,v;
	cin >> n;
	adjacent = vector<vector<int>>(n);
	checked = vector<bool>(n, false);
	ans.resize(n);

	for (int i = 0; i < n; i++) {
		cin >> u >> k;
		for (int j = 0; j < k; j++) cin >> v,adjacent[u - 1].push_back(v-1);
	}
	int time = 1;
	for (int i = 0; i < n; i++) if (!checked[i])time = dfs(i, time)+1;
	for (int i = 0; i < n; i++) 
		cout << i + 1 << " " << ans[i].first << " " << ans[i].second << endl;
}

C++: #include <iostream>
#include <stdio.h>
#include <cstring>
#include <math.h>
#include <algorithm>
#include <vector>
#include <string>
#include <stdlib.h>
#include <queue>
#include <stack>
#include <utility>
#define rep(i,n) for(int i=0;i<n;i++)
#define rrep(i,n) for(int i=n-1;i>=0;i--)
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define ll long long
#define INF 1000000001
#define mod 1000000007
using namespace std;
int dfs(int n,int x,vector<int> k,vector<vector<int>> v,vector<int> &a,vector<int> &b,int &count);


int main(){
	int n;
	cin>>n;
	vector<vector<int> > v(n);
	vector<int> k(n);
	int x;
	rep(i,n){
		cin>>x;
		cin>>k[i];
		v[i].resize(k[i]);
		rep(j,k[i]){
			cin>>v[i][j];
			v[i][j]--;
		}
	}
	vector<int> a(n),b(n);
	int count=1;
	a[0]=1;
	dfs(n,0,k,v,a,b,count);

	rep(i,n){
		if(a[i]==0){
			count++;
			a[i]=count;
			dfs(n,i,k,v,a,b,count);
		}
	}


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

	return 0;
}
int dfs(int n,int x,vector<int> k,vector<vector<int>> v,vector<int> &a,vector<int> &b,int &count){
	/*if(k[x]==0){
		count++;
		a[x]=count;
	}*/
	rep(i,k[x]){
		if(a[v[x][i]]==0){
			count++;
			a[v[x][i]]=count;
			dfs(n,v[x][i],k,v,a,b,count);
		}
		if(i==k[x]-1){
			k[x]=0;
		}
	}
	if(k[x]==0){
		count++;
		b[x]=count;
	}
	return 0;
}

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

using namespace std;

const int N = 105;

int n, k, u, v, clok;
int d[N], f[N], mark[N];
vector<int> a[N];

void DFS(int p)
{
  mark[p] = 1;
  d[p] = clok;
  clok++;
  for(int i = 0; i < a[p].size(); i++)
    if(!mark[a[p][i]]){
      DFS(a[p][i]);
    }
  f[p] = clok;
  clok++;
}

int main()
{
  cin >> n;
  for(int i = 1; i <= n; i++){
    cin >> u >> k;
    for(int j = 1; j <= k; j++) {
      cin >> v;
      a[u].push_back(v);
    }
    sort(a[u].begin(), a[u].end());
  }
  clok = 1;
  for(int i = 1; i <= n; i++)
    if(!mark[i]) DFS(i);
  for(int i = 1; i <= n; i++){
    cout << i << " " << d[i] << " " << f[i] << endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
#define int long long
#define rng(i, l, r) for (size_t i = (l); i < (r); ++i)
#define rep(i, n) rng(i, 0, n)
#define gnr(i, l, r) for (size_t i = (r)-1; i >= (l); i--)
#define per(i, b) gnr(i, 0, b)
#define ALL(obj) (obj).begin(), (obj).end()    //1,2,3,...
#define rALL(obj) (obj).rbegin(), (obj).rend() //...,3,2,1

using namespace std;
const int INF = 1e18;

struct edge
{
    int to;
    int cost;
};
using Graph = vector<vector<edge>>;

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

int n;
Graph G;

int seen[110];
int discover[110];
int finish[110];
int stamp = 0;

void dfs(int cur)
{
    discover[cur] = stamp++;

    seen[cur] = BLACK;
    for (auto ne : G[cur])
    {
        int v = ne.to;
        int vc = ne.cost;
        if (seen[v] == BLACK)
            continue;
        dfs(v);
    }

    finish[cur] = stamp++;
}

void solve()
{

    // remove the bottom 3 lines when you submit this code.
    std::ifstream in("sample.txt");
    std::cin.rdbuf(in.rdbuf());

    cin.tie(0);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;
    G.resize(n + 1);

    for (int i = 0; i <= n; i++)
    {
        if (i == 0)
        {
            for (int j = 1; j <= n; j++)
            {
                G[0].push_back((edge){j, 1});
            }
        }
        else
        {
            int u, k;
            cin >> u >> k;
            for (int j = 0; j < k; j++)
            {
                int v;
                cin >> v;
                G[u].push_back((edge){v, 1});
            }
        }
    }

    for (int i = 0; i < 110; i++)
    {
        seen[i] = WHITE;
        discover[i] = INF;
        finish[i] = INF;
    }

    dfs(0);

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

signed main()
{
    solve();
    return 0;
}

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

int n, t;
int v[100][100];
int d[100], f[100];

void stamp(int id) {
//	if (t > 2 * n)
//		return;
	
	if (d[id - 1] == 0) {
		d[id - 1] = t;
		t++;
		int i = 0;
		while (v[id - 1][i] == 0)
			i++;
		if (i < n && d[i] == 0)
			stamp(i + 1);
		else
			stamp(id);
	}
	else if (f[id - 1] == 0) {
		int i;
		for(i = n - 1; i > -1; i--)
			if (v[id - 1][i] == 1 && d[i] == 0)
				stamp(i + 1);
		if (i < 0 && f[id - 1] == 0) {
			f[id - 1] = t;
			t++;
			for (i = n - 1; i > -1; i--)
				if (v[i][id - 1] == 1 && f[i] == 0)
					stamp(i + 1);
		}
	}
	else
		return;
}

int main()
{
	cin >> n;

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

	for (int i = 0; i < n; i++)
		for (int j = 0; j < n; j++)
			v[i][j] = 0;

	for (int i = 0; i < n; i++) {
		int u, k, s;

		cin >> u >> k;

		for (int j = 0; j < k; j++) {
			cin >> s;
			v[u - 1][s - 1] = 1;
		}
	}

	t = 1;
	stamp(1);

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

	return 0;
}

C++: #include <stdio.h>
#include <iostream>
#include <algorithm>
#include <math.h>
#include <stack>

using namespace std;

int common_time=1,n;

int table[101][101],time_table[101][2];

void func(int node){
	if(time_table[node][0] == 0){
		time_table[node][0] = common_time++;
	}else{
		return;
	}
	for(int i=1;i<=n;i++){
		if(table[node][i] == 1){
			func(i);
		}
	}
	time_table[node][1] = common_time++;
}

int main(){
	int row,num,col;
	scanf("%d",&n);

	for(int i=1;i<=n;i++){
		for(int k=1;k<=n;k++){
			table[i][k]=0;
		}
		time_table[i][0]=0;
		time_table[i][1]=0;
	}

	for(int i=1;i<=n;i++){
		scanf("%d %d",&row,&num);
		for(int k=1;k<=num;k++){
			scanf("%d",&col);
			table[row][col]=1;
		}
	}

	for(int i=1;i<=n;i++){
		func(i);
	}

	for(int i=1;i<=n;i++){
		printf("%d %d %d\n",i,time_table[i][0],time_table[i][1]);
	}

    return 0;
}