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 <stdio.h>
#include <stdint.h>
#include <iostream>
#include <fstream>
#include <cassert>
#include <climits>

#include <vector>
#include <memory>
using namespace std;

#define DEBUG (0)
#define USE_UNIQUE_PTR (0)

#if DEBUG
#define DPRINTF(...) do { \
    printf("D(L%d) %s: ", __LINE__, __func__); \
    printf(__VA_ARGS__); \
  } while (false)
#else
#define DPRINTF(...)
#endif // DEBUG

int g_num = -1;
int g_time = 1;

class Vertex {
public:
  Vertex() :
    id_(-1),
    discover_time_(-1),
    finish_time_(-1),
    adjacentNum_(0),
#if USE_UNIQUE_PTR
    adjacentIds_(nullptr),
#endif
    isVisited_(false) { }

  ~Vertex() {
  }

  void setAdjacency(const vector<int> &adjacentIds);

  inline void setId(int id) { id_ = id; }
  inline void setDiscoverTime(int time) { discover_time_ = time; }
  inline void setFinishTime(int time) { finish_time_ = time; }
  inline void setVisited(bool visited) { isVisited_ = visited; }

  inline int getId() { return id_; }
  inline int getDiscoverTime() { return discover_time_; }
  inline int getFinishTime() { return finish_time_; }
  inline bool getVisited() { return isVisited_; }
  inline int getAdjacentNum() { return adjacentNum_; }
  inline int getAdjacentId(int idx) {
    if (adjacentIds_ == nullptr || idx > adjacentNum_)
      return -1;
    return adjacentIds_[idx];
  }

  void printTime();
  void printAdj();

private:
  int id_;
  int discover_time_;
  int finish_time_;

  int adjacentNum_;
#if USE_UNIQUE_PTR
  unique_ptr<int[]> adjacentIds_;
#else
  static const int kMaxId = 100;
  int adjacentIds_[kMaxId];
#endif // USE_UNIQUE_PTR

  bool isVisited_;
};


void Vertex::setAdjacency(const vector<int> &adjacentIds)
{
#if USE_UNIQUE_PTR
  if (adjacentIds_) assert(1);
#endif // USE_UNIQUE_PTR

  adjacentNum_ = adjacentIds.size();
#if USE_UNIQUE_PTR
  adjacentIds_ = unique_ptr<int[]>(new int[adjacentNum_]);
#endif // USE_UNIQUE_PTR

  for (int i = 0; i < adjacentNum_; i++)
  {
    adjacentIds_[i] = adjacentIds[i];
  }

}

void Vertex::printTime()
{
  printf("%d %d %d\n", id_, discover_time_, finish_time_);
}

void Vertex::printAdj()
{
  DPRINTF("%d %d", id_, adjacentNum_);
  for (int i = 0; i < adjacentNum_; i++) {
    printf(" %d", adjacentIds_[i]);
  }
  cout << endl;
}


void dfs(Vertex vertices[], int idx)
{

  DPRINTF("time %d  idx %d\n", g_time, idx);

  assert(idx <= g_num);

  Vertex &vtx = vertices[idx];

  if (!vtx.getVisited())
  {
    vtx.setDiscoverTime(g_time);
    g_time++;
  }

  for (int i = 0; i < vtx.getAdjacentNum(); i++)
  {
    int id = vtx.getAdjacentId(i);
    dfs(vertices, id);
  }

  if (!vtx.getVisited())
  {
    vtx.setFinishTime(g_time);
    vtx.setVisited(true);
    g_time++;
  }

}


int main()
{
  //int n;

  //cin >> n; cin.ignore();
  cin >> g_num; cin.ignore();
  DPRINTF("Node num %d\n", g_num);

  Vertex vertices[g_num+1];

  for (int i = 1; i <= g_num; i++)
  {
    int id;
    int num;

    cin >> id >> num;
    vertices[i].setId(id);
    DPRINTF("node %d (num %d)\n", id, num);

    vector<int> adjs;

    for (int j = 0; j < num; j++)
    {
      int adj;
      cin >> adj;

      adjs.push_back(adj);
    }

    if (adjs.size())
      vertices[i].setAdjacency(adjs);

    cin.ignore();
  }

#if DEBUG
  for (int i = 1; i <= g_num; i++) vertices[i].printAdj();
#endif

  for (int i = 1; i <= g_num; i++)
    if (!vertices[i].getVisited())
      dfs(vertices, i);

  for (int i = 1; i <= g_num; i++) vertices[i].printTime();

  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]) dfs_visit(u);
	}

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

int main() {
	int k , u, 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 i = 0; i < k; i++) {
	        cin >> v;
	        v--;
		   M[u][v] = 1; 
     	}
	} 
	
	dfs();
	
	return 0;
}

C++: #include <bits/stdc++.h>
#define r(i,a,n) for(int i=a;i<n;i++)
using namespace std;
int a[101][101],start[101],end[101],n,p=0,v[101];
void dfs(int u){
	if(!v[u]){v[u]++;
	start[u]=++p;
	r(i,1,n+1)if(a[u][i])dfs(i);
	end[u]=++p;}
}
int main(){
	int q,qq,qqq;
	cin>>n;
	r(i,0,n){cin>>q>>qq;
		r(i,0,qq){cin>>qqq;
			a[q][qqq]++;
		}
	}
	r(i,1,n+1)if(!v[i])dfs(i);
	r(i,1,n+1)cout<<i<<' '<<start[i]<<' '<<end[i]<<endl;
}

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

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

int N;
int G[MAX_N][MAX_N];
int color[MAX_N], d[MAX_N], f[MAX_N];
int t;

void bfs_visit(int u) {
    color[u] = GRAY;
    d[u] = ++t;
    for (int i = 0; i < N; i++) {
        if (G[u][i] && color[i] == WHITE) {
            bfs_visit(i);
        }
    }
    color[u] = BLACK;
    f[u] = ++t;
}

void dfs() {
    for (int i = 0; i < N; i++) {
        color[i] = WHITE;
    }
    t = 0;
    for (int i = 0; i < N; i++) {
        if (color[i] == WHITE) {
            bfs_visit(i);
        }
    }
    for (int i = 0; i < N; i++) {
        cout << i + 1 << " " << d[i] << " " << f[i] << endl;
    }
}

int main() {
    cin >> N;
    for (int i = 0; i < N; i++) {
        int u, k;
        cin >> u >> k;
        u--;
        for (int j = 0; j < k; j++) {
            int v;
            cin >> v;
            v--;
            G[u][v] = 1;
        }
    }

    dfs();
    return 0;
}