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 <vector>
#include <stack>
#include <queue>

using namespace std;

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

int n, m[N][N], color[N], nxtNei[N];
int t, t1[N], t2[N];

int nxt(int u){
	for (int v = nxtNei[u]; v < n; ++v) {
		nxtNei[u] = v + 1;
		if (color[v] == WHITE && m[u][v] == 1) {
			return v;
		}
	}
	return -1;
}

void dfs(int r){
	for (int i = 0; i < n; ++i) nxtNei[i] = 0;
	stack<int> s;
	color[r] = GREY;
	s.push(r);
	t1[r] = t++;
	while (!s.empty()) {
		int u = s.top();
		int v = nxt(u);
		if (-1 == v){
			color[u] = BLACK;
			s.pop();
			t2[u] = t++;
			continue;
		}

		color[v] = GREY;
		s.push(v);
		t1[v] = t++;
	}
}

void search(){
	t = 1;
	for (int i = 0; i < n; ++i){
		color[i] = WHITE;
		nxtNei[i] = 0;
	}
	for (int i = 0; i < n; ++i) {
		if (color[i] == WHITE) dfs(i);
	}
	for (int i = 0; i < n; ++i){
		cout << i + 1 << " " << t1[i] << " " << t2[i] << endl;
	}
}


int main()
{
	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) {
		int u, d; cin >> u >> d;
		for (int j = 0; j < d; ++j) {
			int v; cin >> v;
			m[u - 1][v - 1] = 1;
		}
	}

	search();

	return 0;
}

C++: #include <utility>
#include <math.h>
#include <vector>
#include <algorithm>
#include <string>
#include <iostream>

using namespace std;

int c;
int a[100][100];
int times = 0;
vector<pair<int,int> > v;

vector<int> search(int node)
{
    vector<int> r;
    for(int i = 0;i<c;i++)
    {
        if(a[node][i] == 1)
            r.push_back(i);
    }
    return r;
}

int deep(int node)
{
    if(v[node].first == 0)
    {
        v[node].first = ++times;
        vector<int> r = search(node);
        for(int i = 0;i<r.size();i++)
        {
            deep(r[i]);
            
        }
        v[node].second = ++times;
    }
    else
        return -1;

    return 1;
}

int main() {

    cin >> c;
    for(int i= 0;i<c;i++)
        for(int j = 0;j<c;j++)
            a[i][j] = 0;
    v = vector<pair<int,int> >(c,{0,0});
    for(int i = 0; i<c;i++)
    {
        int rem[2];
        cin >> rem[0] >> rem[1];
        for(int j = 0;j<rem[1];j++)
        {
            int rem11;
            cin >> rem11;
            a[i][rem11-1] = 1;
        }
    }//cin fin
    for(int i = 0;i<c;i++)
    {
        if(v[i].first == 0)
            deep(i);
    }
    
    for(int i = 0; i<c;i++)
    {
        cout << i+1 << " " << v[i].first << " " << v[i].second << endl;
    }
    
    return 0;
}

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

#define MAX 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
#define NIL -1

using namespace std;

int adj[MAX+1][MAX+1];
int color[MAX+1],d[MAX+1],f[MAX+1];
stack<int> S;
int n;
int t=0;

int next(int u){
  for(int i=1;i<=n;i++){
    if(adj[u][i]==1&&color[i]==WHITE) return i;
  }
  return NIL;
}

void dfs(int u){
  S.push(u);
  color[u]=GRAY;
  d[u]=++t;
  while(S.empty()==false){
    u=S.top();
    int v=next(u);
    if(v!=NIL){
      color[v]=GRAY;
      d[v]=++t;
      S.push(v);
    }else{
      S.pop();
      color[u]=BLACK;
      f[u]=++t;
    }
  }
}

void dfs_init(){
  for(int i=1;i<=n;i++) color[i]=WHITE;
  dfs(1);
}

int main(){
  cin >> n;
  for(int i=1;i<=n;i++){
    int u,k; cin >> u >> k;
    for(int i=1;i<=n;i++) adj[u][i]=0;
    for(int i=0;i<k;i++){
      int v; cin >> v;
      adj[u][v]=1;
    }
  }
  dfs_init();
  for(int id=1;id<=n;id++){
    printf("%d %d %d\n",id,d[id],f[id]);
  }
}

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

const int Max = 100;
const int white = 0;
const int gray = 1;
const int black = 2;

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

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=00; 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;

}