Go: package main

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

var sc = bufio.NewScanner(os.Stdin)
var depth [101]int
var finish [101]int
var d [101]int
var n, time int

func nextInt() int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return i
}
func visit(graph [][]int, u int) {
	depth[u] = 1
	time++
	d[u] = time
	for i := 0; i < n; i++ {
		if graph[u][i] == 1 {
			if depth[i] == 0 {
				visit(graph, i)
			}
		}
	}
	depth[u] = 2
	time++
	finish[u] = time
}
func main() {
	sc.Split(bufio.ScanWords)

	n = nextInt()
	graph := make([][]int, n)
	for i := 0; i < n; i++ {
		graph[i] = make([]int, n)
	}
	for i := 0; i < n; i++ {
		s := nextInt()
		t := nextInt()
		if t == 0 {
			continue
		}
		for i := 0; i < t; i++ {
			u := nextInt()
			graph[s-1][u-1] = 1
		}
	}
	for i := 0; i < n; i++ {
		if depth[i] == 0 {
			visit(graph, i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, d[i], finish[i])
	}
}

C++: #include <iostream>
#include <cstdio>
#include <cstring>
#include <sstream>
#include <algorithm>
#include <math.h>
#include <map>
#include <functional>
#include <iomanip>
#include <vector>
#include <queue>
#include <stack>
#include <set>
#include <typeinfo>
#define PI 3.14159265359
#define INF 99999999;
#define rep(i, n) for(int i=0; i<n; i++)
#define REP(n) rep(i, n)
#define EPS 1e-10
typedef long long ll;
using namespace std;
typedef pair<int, int> P;

double distanceAB(double xa, double ya, double xb, double yb);
//void trace(int A[], int N);

/*
class Target
{
public:
	vector <string> draw(int n)
	{

	}
};
*/


#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;
	rep(v, n)
	{
		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);
	rep(i, n) rep(j, n) M[i][j] = 0;
	
	rep(i, n)
	{
		scanf("%d %d", &u, &k);
		u--;
		rep(j, k)
		{
			scanf("%d", &v);
			v--;
			M[u][v] = 1;
		}
	}
	
	dfs();
	
	return 0;
}

/*
void trace(int A[], int N)
{
	REP(N)
	{
		if (i > 0) cout << " ";
		cout << A[i];
	}
	cout << endl;
}
*/


double distanceAB(double xa, double ya, double xb, double yb)
{
	return sqrt((xb-xa)*(xb-xa) + (yb-ya)*(yb-ya));
}

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

using namespace std;

static const int N = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int n, M[N][N];
int color[N], d[N], f[N], tt;
int nt[N];

int next(int u){
  for(int v = nt[u]; v < n; v++){
    nt[u] = v + 1;
    if(M[u][v]) return v;
  }
  return -1;
}

void dfs_visit(int r){
  for(int i = 0; i < n; i++) nt[i] = 0;

  stack<int> S;
  S.push(r);
  color[r] = GRAY;
  d[r] = ++tt;

  while(!S.empty()){
    int u = S.top();
    int v = next(u);

    if(v != -1){
      if(color[v] == WHITE){
	color[v] = GRAY;
	d[v] = ++tt;
	S.push(v);
      }
    }
    else {
      S.pop();
      color[u] = BLACK;
      f[u] = ++tt;
    }
  }
}

void dfs(){
  for(int i = 0; i < n; i++){
    color[i] = WHITE;
    nt[i] = 0;
  }
  tt = 0;

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

int main(){
  int u, k, v;

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

  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
void func(int p);
int n;
int box[101][101];
int d[101];
int f[101];
int flg[101];
int t;
int main(void){
	int u,k,v;
	int i,j;
	cin>>n;
	for(i=1;i<=n;i++){
		for(j=1;j<=n;j++){
			box[i][j]=0;
		}
	}
	for(i=0;i<n;i++){
		cin>>u>>k;
		for(j=0;j<k;j++){
			cin>>v;
			box[u][v]=1;
		}
	}
	t=0;
	for(i=1;i<=n;i++){
		if(!flg[i]){
			func(i);
		}
	}
	for(i=1;i<=n;i++)	cout<<i<<" "<<d[i]<<" "<<f[i]<<endl;
	return 0;
}
void func(int p){
	int i;
	t++;
	d[p]=t;
	flg[p]=true;
	for(i=1;i<=n;i++){
		if(box[p][i]==1){
			if(!flg[i]){
				func(i);
			}
		}
	}
	t++;
	f[p]=t;
}

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

int g[101][101], d[101], f[101];

int dfs(int id, int t)
{
    if(d[id]) return t;
    d[id]=++t;
    int n=g[id][0];
    for(int i=1; i<=n; i++) {
        t=dfs(g[id][i], t);
    }
    f[id]=++t;
    return t;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin>>n;
    for(int i=0; i<n; i++) {
        int id, k;
        cin>>id>>k;
        g[id][0]=k;
        for(int j=1; j<=k; j++) {
            cin>>g[id][j];
        }
    }
    dfs(1, 0);
    for(int i=1; i<=n; i++) {
        cout<<i<<' '<<d[i]<<' '<<f[i]<<'\n';
    }
    return 0;
}

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

using namespace std;

int d[10010]={0};//最初に訪問した時刻を入れるタイムスタンプ
int f[10010]={0};//vの隣接リストを調べ終えた時刻のタイムスタンプ

int back[10010]={0};//番号nのもときた街番号をいれる

int g[1001][1001]={{0}};//要素を0で初期化
int timestamp = 1;
int number;
int dfs(int cur){
  timestamp += 1;
  for(int dst = 0; dst < number; dst++){
    if(g[cur][dst]==1 && d[dst]==0){
      d[dst]=timestamp;
      back[dst]=cur;
      dfs(dst);
    }
  }
  // timestamp += 1;
  // cout << "f[cur]" <<f[cur]<<"timestamp"<<timestamp<<"cur"<<cur<<endl;
  // abort();
  if(timestamp > number*2){
    return 0;
  }
  // cout << "f[cur]" <<f[cur]<<"timestamp"<<timestamp<<"cur"<<cur<<endl;
  // abort();
  f[cur]=timestamp;
  dfs(back[cur]);
}
void ans(int n){
  for (int i = 0; i < n; ++i)
  {
    cout << i+1 << " " << d[i] <<" "<< f[i] <<endl;
  }
}

int main(){
  // int g[1001][1001]={{0}};//要素を0で初期化
  int n,a,b,c;
  cin >> n;
  number = n;
  for (int i = 0; i < n; ++i)
  {
    cin >> a >> b ;
    for (int i = 0; i < b; ++i)
    {
      cin >> c;
      g[a-1][c-1]=1;/* code */
    }
  }
  d[0]=1;
  dfs(0);
  for (int i = 0; i < number; ++i)
  {
    if(d[i]==0){
      dfs(i);
    }
  }
  // for (int i = 0; i < number; ++i)
  // {
  //   cout << back[i]<<" ";
  // }

  ans(n);
}

C++: /*
    Problem 24
    https://onlinejudge.u-aizu.ac.jp/problems/ALDS1_11_B
*/
#include <bits/stdc++.h>
using namespace std;
/* typedef */
typedef long long ll;
typedef pair<int, int> pii;
/* constant */
const int INF = 1 << 30;
const ll LINF = 1LL << 50;
const int NIL = -1;
const int MAX = 102;
const int mod = 1000000007;
const double pi = 3.141592653589;
/* global variables */
vector<vector<int>> G(MAX, vector<int>());
vector<int> d(MAX), f(MAX), deg(MAX), cur(MAX);
int t = 1;
/* function */
void dfs(int st) {
    stack<int> S;
    S.push(st);
    d[st] = t++;
    while (!S.empty()) {
        int from = S.top();
        if (cur[from] >= deg[from]) {
            f[from] = t++;
            S.pop();
            continue;
        }
        int to = G[from][cur[from]++];
        if (d[to] != 0) continue;
        d[to] = t++;
        S.push(to);
    }
}
/* main */
int main(){
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
        int u, k, v;
        cin >> u >> k;
        u--;
        deg[u] = k;
        for (int j = 0; j < k; j++) {
            cin >> v;
            v--;
            G[u].push_back(v);
        }
    }

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

    for (int i = 0; i < n; i++)
        cout << i + 1 << ' ' << d[i] << ' ' << f[i] << '\n';
}