Go: package main

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

const MAX = 101

var f [MAX]int
var d [MAX]int
var list [][]int
var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func dfs(u, cnt int) int {
	if d[u] != 0 {
		return cnt
	}

	cnt++
	d[u] = cnt
	for _, next := range list[u] {
		cnt = dfs(next, cnt)
	}
	cnt++
	f[u] = cnt
	return cnt
}

func main() {
	n := scanInt()
	list = make([][]int, n+1)
	for i := 1; i <= n; i++ {
		u := scanInt()
		k := scanInt()
		for j := 0; j < k; j++ {
			n := scanInt()
			list[u] = append(list[u], n)
		}
	}

	cnt := 0
	for i := 1; i <= n; i++ {
		cnt = dfs(i, cnt)
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 1; i <= n; i++ {
		fmt.Fprint(w, i)
		fmt.Fprint(w, " ")
		fmt.Fprint(w, d[i])
		fmt.Fprint(w, " ")
		fmt.Fprint(w, f[i])
		fmt.Fprintln(w)
	}
	w.Flush()
}

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

static const int MAX_NUM = 101;
static const int NO_VISIT  = 0;
static const int NOW_VISIT = 1;
static const int END_VISIT = 2;

void DSF(int* matrix, int num)
{
    int i, j;
    int ttime = 0;
    int stime[MAX_NUM+1] = {0};
    int etime[MAX_NUM+1] = {0};
    int state[MAX_NUM+1] = {0};
    stack<int> S;
    int target, next;
    int *tmp;

    for (j = 1; j <= num; j++) {
        if (state[j] != NO_VISIT) {
            continue;
        }
        S.push(j);
        ++ttime;
        stime[j] = ttime;
        state[j] = NOW_VISIT;

        while (S.empty() == false) {
            target = S.top();
            for (i = 1; i <= num; i++) {
                tmp = matrix + MAX_NUM * target + i;
                if ((*tmp == 1) && (state[i] == NO_VISIT)) {
                    *tmp = 2;
                    S.push(i);
                    ++ttime;
                    stime[i] = ttime;
                    state[i] = NOW_VISIT;
                    break;
                }
            }

            if (i == num + 1) {
                S.pop();
                ++ttime;
                etime[target] = ttime;
                state[target] = END_VISIT;
            }
        }
    }

    for (i = 1; i <= num; i++) {
        printf("%d %d %d\n", i, stime[i], etime[i]);
    }

    return;
}

int main(void)
{
    int i, j;
    int num;
    int elem;
    int nume;
    int tmp;
    int matrix[MAX_NUM][MAX_NUM] = {0};

    scanf("%d", &num);

    for (i = 0; i < num; i++) {
        scanf("%d %d", &elem, &nume);
        for (j = 0; j < nume; j++) {
            scanf("%d", &tmp);
            matrix[elem][tmp] = 1;
        }
    }

    DSF(&matrix[0][0], num);

    return 0;
}

C++: #include <iostream>
#include <utility>
#define N 	100

using namespace std;

int T[N+1][N+1];
pair<int , int> M[N+1];
int t = 0;

void init(){
	for (int i = 0; i < 100; ++i)
	{
		M[i].first = 0;
		M[i].second = 0;
		for (int j = 0; j < 100; ++j)
		{
			T[i][j] = 0;
		}
	}
}

void DispTable(int n){
	for (int i = 1; i <= n; ++i)
	{
		for (int j = 1; j <= n; ++j)
		{
			cout << T[i][j];
			if(j!=n) cout << " ";
		}
		cout << endl;
	}
}

void DispM(int n){
	for (int i = 1; i<=n; i++)
	{
		cout << i << " " << M[i].first << " " << M[i].second << endl;
	}
}

void dfs(int cur,int n){
	t++;
	M[cur].first = t;
	// cerr << "visiting " << cur << " " << t << endl;

	for (int i = 1; i <= n; ++i)
	{
		if(T[cur][i] == 1 && M[i].first == 0) dfs(i,n);
	}
	t++;
	M[cur].second = t;
}

int main(){
	int n;
	cin >> n;
	init();
	for (int i = 0; i < n; ++i)
	{
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; ++j)
		{
			int v;
			cin >> v;
			T[u][v] = 1;	
		}
	}
	// DispTable(n);
	dfs(1,n);
	DispM(n);
	return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <stack>
#include <queue>
#include <vector>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>

using namespace std;

struct Node {
	int k, d, f;
	vector<int> v;
};

#define MAX_N 100

Node node[MAX_N + 1];
int stamp = 1;

void dfs(int u) {
	if (node[u].d == 0) {
		node[u].d = stamp++;
		for (int i = 0; i < node[u].k; ++i)
			if (node[u].v[i] != u)
				dfs(node[u].v[i]);
		if (node[u].f == 0) node[u].f = stamp++;
	}
}

int main() {
	int n;
	cin >> n;
	for (int i = 0; i < n; ++i) {
		int u;
		cin >> u;
		cin >> node[u].k;
		for (int j = 0; j < node[u].k; ++j) {
			int v;
			cin >> v;
			node[u].v.push_back(v);
		}
		node[u].d = node[u].f = 0;
	}
	for (int i = 1; i <= n; ++i)
		dfs(i);
	for (int i = 1; i <= n; ++i)
		cout << i << " " << node[i].d << " " << node[i].f << endl;
	return 0;
}

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


int d[200] = {}, f[200] = {};

vector<int> G[200];

int func(int pos, int time){
  if(d[pos] > 0){
    return time;
  }
  d[pos] = time;
  time += 1;
  for(int to : G[pos]){
    time = func(to, time);
  }
  f[pos] = time;
  time += 1;
  return time;
}


int main(){
	// input

	int n;
	cin >> n;

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

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

	}
	return 0;
}

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

struct StSeq
{
  int m_nBgn;
  int m_nEnd;

  StSeq() : m_nBgn(0), m_nEnd(0)
  { }
};

void fnInput(vector<vector<int>>& rvvnAdjcy, vector<StSeq>& rvoDFSrch)
{
  int nMaxSiz;
  cin >> nMaxSiz;

  rvvnAdjcy.resize(nMaxSiz + 1, vector<int>(nMaxSiz + 1, 0));
  for (int i = 0; i < nMaxSiz; ++i)
  {
    int nx, nSecSiz;
    cin >> nx >> nSecSiz;
    for (int j = 0; j < nSecSiz; ++j)
    {
      int ny;
      cin >> ny;
      rvvnAdjcy[nx][ny] = 1;
    }
  }
  StSeq oSeq;
  rvoDFSrch.resize(nMaxSiz + 1, oSeq);
}

void fnDepthFirstSearch(const vector<vector<int>>& cnrvvnAdjcy, vector<StSeq>& rvoDFSrch, int nx)
{
  static int stnCnt = 0;

  if (rvoDFSrch[nx].m_nEnd)  return;
  rvoDFSrch[nx].m_nBgn = ++stnCnt;

  for (int ny = 1; ny < cnrvvnAdjcy.size(); ++ny)
    if (cnrvvnAdjcy[nx][ny] == 1  &&
        nx != ny               )
      fnDepthFirstSearch(cnrvvnAdjcy, rvoDFSrch, ny);

  rvoDFSrch[nx].m_nEnd = ++stnCnt;
}

void fnResult(const vector<StSeq>& cnrvoDFSrch)
{
  for (int i = 1; i < cnrvoDFSrch.size(); ++i)
    cout << i <<  " " << cnrvoDFSrch[i].m_nBgn << " " << cnrvoDFSrch[i].m_nEnd << endl;
}

int main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);
  vector<vector<int>> vvnAdjcy;
  vector<StSeq> voDFSrch;

  fnInput(vvnAdjcy, voDFSrch);
  for (int nx = 1; nx < voDFSrch.size(); ++nx)
    fnDepthFirstSearch(vvnAdjcy, voDFSrch, nx);
  fnResult(voDFSrch);

  return 0;
}

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, tt;
int M[N][N], color[N], d[N], f[N], 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 {
		   color[u] = BLACK;
		   S.pop();
		   f[u] = ++tt;
		}
	} 
}


void dfs() {
	for(int i = 0; i < n; i++) {
	     color[i] = WHITE;
	}
	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 n, k , u, v;
	cin >> n;
	for(int i = 0; i < n; i++) {
		for(int j = 0; j < n; j++) {
			M[i][j] = 0;
		}
	}
	cin >> u >> k;
	u--;
	for(int i = 0; i < k; i++) {
	    cin >> v;
	    v--;
		M[u][v] = 1; 
	}
	dfs();
	return 0;
}