Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

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

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve

const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 最初にiを訪問した時刻。発見時刻
//f[i]: iの隣接リストを訪問し終えた時刻。完了時刻
var color, d, f [MAX]int

func dfs_visit(u int) {
	color[u] = GRAY
	time++
	d[u] = time
	//隣接を調べる
	for v := 0; v < n; v++ {
		if M[u][v] == 0 {
			continue
		}
		//隣接するvが、未訪問だった場合
		if color[v] == WHITE {
			dfs_visit(v)
		}
	}
	//訪問完了処理
	color[u] = BLACK
	time++
	f[u] = time
	//訪問完了
}

func dfs() {
	//初期化
	for u := 0; u < n; u++ {
		color[u] = WHITE
	}
	time = 0

	//未訪問のuを始点として、深さ優先探索
	for u := 0; u < n; u++ {

		if color[u] == WHITE {
			dfs_visit(u)
		}
	}

	for u := 0; u < n; u++ {
		fmt.Println(u+1, d[u], f[u])
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	dfs()

}

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

const int MAXINT = 10000000;

// typedef std::vector<std::vector<int> > mat_int;
// typedef std::vector<std::vector<bool> > mat_bool;

void dfs(std::vector<std::vector<int> >& adj_list, std::vector<int>& d, std::vector<int>& f, int& time, int root = 0 ){
  assert(d[root] > time);
  {
    // std::cout << root << ", " << time << std::endl;
    d[root] = time;
    for(int const& v: adj_list[root]){
      if(d[v] > time){
        time++;
        // std::cout << "call: " << root+1 << " " << v+1 << std::endl;
        dfs(adj_list, d, f, time, v);
      }
    }
    time++;
    // std::cout << "done: " << std::endl;
    f[root] = time;
  }

}


int main(int argc, char const *argv[]) {
  int n; // .. 100
  std::cin >> n;
  // mat_bool adj(n, std::vector<bool>(n));
  // mat_int d(n, std::vector<int>(n)), f(n, std::vector<int>(n));
  std::vector<std::vector<int> > adj_list(n);
  std::vector<int> d(n, MAXINT), f(n, MAXINT);

  for(int q=0; q<n; ++q){
    int i_plus_1, k;
    std::cin >> i_plus_1;
    std::cin >> k;
    for(int p=0; p<k; ++p){
      int j_plus_1;
      std::cin >> j_plus_1;
      // adj[i_plus_1-1][j_plus_1-1] = true;
      adj_list[i_plus_1 - 1].push_back(j_plus_1-1);
    }
  }

  int t = 0;
  // dfs(adj_list, d, f, t);
  for(int i=0; i<n; ++i){
    if(d[i] == MAXINT){
      ++t;
      dfs(adj_list, d, f, t, i);
    }
  }


  for(int i=0; i<n; ++i){

    // if(d[i] < MAXINT){
      std::cout << (i+1)
        << " " << d[i]
        << " " << f[i]
        << std::endl;
    // }
    // else{
    //   std::cout << (i+1)
    //     << " " << d[i]
    //     << " " << f[i]
    //     << std::endl;
    // }


  }


  // for(auto it = adj_list.begin(); it != adj_list.end(); ++it){
  //   std::cout << ": ";
  //   for(auto jt = (*it).begin(); jt != (*it).end(); ++jt){
  //     std::cout << (*jt) << ' ';
  //   }
  //   std::cout << std::endl;
  // }

  return 0;
}

C++: //
// Created by tattsun on 2017/02/13.
//

#include <iostream>
#include <vector>

using namespace std;

#define VERTEX_MAX_NUM 101
#define NIL -1

int now = 0;
int n;
int start[VERTEX_MAX_NUM];
int finish[VERTEX_MAX_NUM];
bool visited[VERTEX_MAX_NUM];
vector<int> vertexes[VERTEX_MAX_NUM];

void _dfs(int node) {
    cout << node << endl;
    start[node] = ++now;
    visited[node] = true;

    auto& v = vertexes[node];

    for(auto it = v.begin(); it != v.end(); it++) {
        if(visited[*it])
            continue;
        _dfs(*it);
    }

    finish[node] = ++now;
}

void dfs() {
    _dfs(1);
}

int main() {
    for(int i=0; i<VERTEX_MAX_NUM; i++) {
        start[i] = NIL;
        finish[i] = NIL;
        visited[i] = false;
    }

    cin >> n;

    int u, k, p;
    for(int i=1; i<=n; i++) {
        cin >> u >> k;
        for(int j=0; j<k; j++) {
            cin >> p;
            vertexes[i].push_back(p);
        }
    }

    dfs();

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

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

stack<int> S;
int n, x[10000][10000], a, b, c, d, time=2;
int y[10000][3];

int main() {
	cin >> n;
	for (int i = 1; i <= n; i++) {
		cin >> b >> c;
		for (int j = 1; j <= c; j++) {
			cin >> d;
			x[i][d] = 1;
		}
	}
	S.push(1);
	y[1][1] = 1;
	while (!S.empty()) {
		a = S.top();
		for (int i = 1; i <= n; i++) {
			if (x[a][i] == 1 && y[i][0] == 0) {
				y[i][0] = 1;
				y[i][1] = time;
				S.push(i);
				goto Exit;
			}
		}
		S.pop();
		y[a][2] = time;
	Exit:;
		time++;
	}
	for (int i = 1; i <= n; i++) {
		cout << i << ' ' << y[i][1] << ' ' << y[i][2] << endl;
	}
	return 0;
}

C++: #include<cstdio>
#include<iostream>
#include<cstring>
#define white 0
#define gray 1
#define black 2
using namespace std;
const int MAXN = 100+10 ;

int a[MAXN][MAXN],flag[MAXN],d[MAXN],f[MAXN],cnt;
int n,u,v,t;

void fun(int x)
{
    flag[x] = gray;
    d[x] = ++cnt;
    for(int i = 1; i <= n; ++i)
    {
        if(a[x][i] && flag[i]==white)
            fun(i);
    }
    flag[x] = black;
    f[x] = ++cnt;
    return;
}

void dfs()
{
    memset(flag,0,sizeof flag);
    for(int i = 1; i <= n; ++i)
    {
        if(flag[i] == white)
            fun(i);
    }
    for(int i = 1; i <= n; ++i)
        cout<<i<<' '<<d[i]<<' '<<f[i]<<'\n';
}
int main(void)
{

    cin>>n;
    for(int i = 1; i <= n; ++i)
    {
        cin>>u>>t;
        for(int j = 1; j <= t; ++j)
        {
            cin>>v;
            a[u][v] = 1;
        }
    }
    dfs();
}

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


using namespace std;

int timecount = 0;

void dfs(int cur, int u, bool* visited, int* timearray, int* timearray_end, unordered_map<int, vector<int> > mymap);

int main(){
  int u, i, id, k, j;
  cin >> u;
  unordered_map<int, vector<int> > mymap;

  for (i = 0; i < u; ++i){
    cin >> id >> k;
    vector<int> points;
    for (j = 0; j < k; ++j){
      int a;
      cin >> a;
      points.push_back(a);
    }
    mymap[id] = points;
  }
  
  bool visited[u+1];
  for (j = 1; j <= u; ++j){
    visited[j] = false;
  }
  visited[1] = true;

  int timearray[u+1];
  for (j = 1; j <= u; ++j){
    timearray[j] = 0;
  }
  int timearray_end[u+1];
  for (j = 1; j <= u; ++j){
    timearray_end[j] = 0;
  }

  dfs(1, u, visited, timearray, timearray_end, mymap);

  for (j = 1; j <= u; ++j){
    cout << j << " " << timearray[j] << " " << timearray_end[j]<< endl;
  }

}

void dfs(int cur, int u, bool* visited, int* timearray, int* timearray_end, unordered_map<int, vector<int> > mymap){
  timecount++;
  timearray[cur] = timecount;

  for(int i = 1; i <= u; ++i){
    
    if((i!=cur)&&(find(mymap[cur].begin(), mymap[cur].end(), i) != mymap[cur].end())&&(!visited[i])){
      visited[i] = true;
      dfs(i, u, visited, timearray, timearray_end, mymap);
    }
  }
  timecount++;

  timearray_end[cur] = timecount;
}