Go: package main

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

/***************************************************************
stackによる深さ優先探索を実装する。
***************************************************************/

const (
	N     = 100
	WHITE = 0
	GRAY  = 1
	BLACK = 2
)

var (
	n            int
	Adj          [N][N]int
	statusColor  [N]int
	discoverTime [N]int
	finishTime   [N]int
	clock        int
	nt           [N]int
)

/***************************************************************
Stackの定義:
- field
	container: ノードの格納されたスライス
	sp: スタックポインタ
- method
	size(): スタックに積まれているノードの個数を返す
	top(): スタックの一番上に積まれているノードを返す
	isEmpty(): スタックが空かどうかを返す
	pop(): スタックの要素をポップし削除する
	push(): スタックに要素を積む
***************************************************************/

type Stack struct {
	container []int
	sp        int
}

func (s *Stack) size() int {
	return len(s.container)
}

func (s *Stack) top() int {
	return s.container[s.sp]
}

func (s *Stack) isEmpty() bool {
	return s.sp == 0
}

func (s *Stack) pop() int {
	_pop := func() {
		s.container = s.container[:len(s.container)-1]
	}
	defer _pop()
	if s.isEmpty() {
		panic("There is no elements in stack!")
	}
	s.sp--
	return s.container[s.sp]
}

func (s *Stack) push(n int) {
	s.sp++
	s.container[s.sp] = n
}

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

func _DFS(target int) {
	for i := 0; i < n; i++ {
		nt[i] = 0
	}
	stack := new(Stack)
	stack.container = make([]int, N+1)
	stack.push(target)
	statusColor[target] = GRAY
	clock++
	discoverTime[target] = clock
	for !stack.isEmpty() {
		u := stack.top()
		v := next(u)
		if v != -1 {
			if statusColor[v] == WHITE {
				statusColor[v] = GRAY
				clock++
				discoverTime[v] = clock
				stack.push(v)
			}
		} else {
			stack.pop()
			statusColor[u] = BLACK
			clock++
			finishTime[u] = clock
		}
	}
}

func DFS() {
	for i := 0; i < n; i++ {
		statusColor[i] = WHITE
		nt[i] = 0
	}
	clock = 0
	for i := 0; i < n; i++ {
		if statusColor[i] == WHITE {
			_DFS(i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, discoverTime[i], finishTime[i])
	}
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ = strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			Adj[i][j] = 0
		}
	}
	for i := 0; i < n; i++ {
		scanner.Scan()
		u, _ := strconv.Atoi(scanner.Text())
		scanner.Scan()
		k, _ := strconv.Atoi(scanner.Text())
		u--
		for j := 0; j < k; j++ {
			scanner.Scan()
			v, _ := strconv.Atoi(scanner.Text())
			v--
			Adj[u][v] = 1
		}
	}

	DFS()
}

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

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

int a[100][100];
int n,p,q,r;
int T[100],F[100];
int Time = 0;
void dfs(int cur) {
	T[cur] = Time;
	Time += 1;
	for (int dst=0; dst < n; ++dst) {
		if(a[cur][dst] == 1 && T[dst] == -1) {
			dfs(dst);
		}
	}
	F[cur] = Time;
	Time += 1;
}

int main() {
	cin >> n;
	for (int i=0; i<n; ++i) {
		cin >> p >> q;
		T[i] = -1;
		for (int j=0; j<q; ++j) {
			cin >> r;
			a[p-1][r-1] = 1;
		}
	}
	dfs(0);
	for (int i=0; i<n; ++i) {
		cout << i+1 << " " << T[i]+1 << " " << F[i]+1 << endl;
	}
}

C++: #include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<cmath>

#define FOR(i,a,b) for(int i=(a);i<(b);++(i))
#define REP(i,n) FOR(i,0,n)

#define dump(x) cerr << #x << " = " <<(x)<<endl;
#define debug(x) cerr << #x << " = " <<(x) << "(L" << __LINE__ << ")" << __FILE__ << endl;

using namespace std;
typedef vector<vector<int>> VVI;

VVI mat;
vector<int> d,f,color;
int tt,n;

void dfs_visit(int i){
  int v;
  color[i] = 1;
  d[i]=++tt;
  REP(v,n){
    if(mat[i][v]==0) continue;
    if(color[v]==0){
      dfs_visit(v);
    }
  }
  color[i] = 2;
  f[i] = ++tt;
}
void dfs(int n){
  tt=0;

  int i;
  REP(i,n){
    if(color[i]==0) dfs_visit(i);
  }

  REP(i,n) cout << i+1 << " " << d[i] << " " << f[i] << endl;
}

int main(void){
  int q,k,i,l;
  cin >> n;
  mat=VVI(n, vector<int>(n));
  color=d=f=vector<int>(n);
  REP(i,n){
    cin >> l; l--;
    cin >> q;
    REP(j,q){
      cin >> k; k--;
      mat[l][k]=1;
    }
  }
  dfs(n);

  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;

int n,t;
int d[100],f[100];
bool graph[100][100], visited[100];

void dfs(int v){
    visited[v]=true;
    t++;
    d[v]=t;

    for(int v2=0; v2<n; v2++){
        if(graph[v][v2] && visited[v2]==false) dfs(v2);
    }

    t++;
    f[v]=t;
}

int main(void){
    cin >> n;
    t=0;

    for(int i=0; i<n; i++){
        for(int j=0; j<n; j++){
            graph[i][j]=false;
        }
    }
    for(int i=0; i<n; i++){
        int v,k; cin >> v >> k;
        for(int j=0; j<k; j++){
            int w; cin >> w;
            graph[v-1][w-1]=true;
        }
    }

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


}

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 nKey)
{
  static int stnCnt = 0;

  if (rvoDFSrch[nKey].m_nBgn == 0)
    rvoDFSrch[nKey].m_nBgn = ++stnCnt;

  for (int j = 1; j < cnrvvnAdjcy.size(); ++j)
    if (cnrvvnAdjcy[nKey][j] == 1)
      fnDepthFirstSearch(cnrvvnAdjcy, rvoDFSrch, j);

  if (rvoDFSrch[nKey].m_nEnd == 0)
    rvoDFSrch[nKey].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);
  fnDepthFirstSearch(vvnAdjcy, voDFSrch, 1);
  fnResult(voDFSrch);

  return 0;
}