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<string>
#include<cmath>
#include<algorithm>
#include<cctype>
#include<queue>
#include<stack>
#include<stdio.h>
#include<vector>
#include<set>
#include<map>
#include<array>
#include<iomanip>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
int ms[100][100],n,tt=0;
int color[101],nt[101];
int d[100],f[100];
int next(int v){
    for(int i=nt[v];i<n;i++){
        nt[v]=i+1;
        if(ms[v][i]==1)return i;
    }
    return -1;
}

void visit_dfs(int v){
    stack<int> s;
    s.push(v);
    d[v]=++tt;
    color[v]=1;
    while(!s.empty()){
        int u=s.top();
        int uu=next(u);
        if(uu!=-1){
            if(color[uu]==0){
            s.push(uu);
            d[uu]=++tt;
            color[uu]=1;
            }
        }else{
            s.pop();
            f[u]=++tt;
            color[u]=2;
        }
    }
    
    
}
void dfs(){
    for(int i=0;i<n;i++){
        color[i]=0;
        nt[i]=0;
    }
    for(int i=0;i<n;i++){
        if(color[i]==0){
            visit_dfs(i);
        }
    }
    for(int i=0;i<n;i++){
        cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
    }
}

int main(){
    
    cin>>n;
    rep(i,n){
        int a,b,c;
        cin>>a>>b;
        a--;
        rep(j,b){
            cin>>c;
            c--;
            ms[a][c]=1;
        }
    }
    
    dfs();
    return 0;

    
}

C++: #include <iostream>
#include <stack>
#define N 100
#define WHITE 0
#define GRAY  1
#define BLACK 2
#define NIL -1

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

// uの隣接点を番号順に取得する
// nt[N]には番号順での探索開始位置を保存する
// 隣接点がなければ-1を返す
int next(int u)
{
	for (int v = nt[u]; v < n; v++)
	{
		nt[u]++;
		if (M[u][v]) return v;
	}
	return NIL;
}

// rを開始地点として深さ優先探索を行う
void dfs_visit(int r)
{
	std::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 != NIL)
		{
			if (color[v] == WHITE)
			{
				S.push(v);
				color[v] = GRAY;
				d[v] = tt++;
			}
		}
		else
		{
			S.pop();
			color[u] = BLACK;
			f[u] = tt++;
		}
	}
}

//初期化処理、探索、結果出力を行う
void dfs()
{
	for (int i = 0; i < n; i++)
	{
		color[i] = WHITE;
		nt[i] = 0;
	}
	tt = 1;

	for (int i = 0; i < n; i++)
	{
		if (color[i] == WHITE) dfs_visit(i);
	}

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

int main()
{
	std::cin >> n;
	for (int i = 0; i < n; i++)
	{
		for (int j = 0; j < n; j++)
		{
			M[i][j] = 0;
		}
	}

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

	dfs();
}

C++: #include <iostream>
#include <stack>
using namespace std;
const int MAX_N = 100;

int A[MAX_N+1][MAX_N+1];
pair<int, int> TIMESTAMPS[MAX_N+1];
int N;

void solve() {
  int ts = 0;
  stack<int> S;

  for (int i = N; i > 0; i--) {
    if (TIMESTAMPS[i].first == 0) S.push(i);
  }

  while (!S.empty()) {
    int c = S.top();

    if (TIMESTAMPS[c].first == 0)
      TIMESTAMPS[c].first = ++ts;

    for (int i = N; i > 0; i--) {
      if (A[c][i] == 1 && TIMESTAMPS[i].second == 0)
        S.push(i);
    }

    if (S.top() == c) {
      if (TIMESTAMPS[c].second == 0)
        TIMESTAMPS[c].second = ++ts;
      S.pop();
    }
  }
}

int main() {
  cin >> N;

  for (int i = 1; i <= N; i++) {
    for (int j = 1; j <= N; j++) {
      A[i][j] = 0;

    }
    TIMESTAMPS[i] = make_pair(0, 0);
  }

  for (int i = 0; i < N; i++) {
    int u, k; cin >> u >> k;
    for (int j = 0; j < k; j++) {
      int t; cin >> t;
      A[u][t] = 1;
    }
  }

  solve();

  for (int i = 1; i <= N; i++) {
    cout << i << ' '
         << TIMESTAMPS[i].first << ' '
         << TIMESTAMPS[i].second << endl;
  }

  return 0;
}

C++: #include <iostream>
 
using namespace std;
 
    int TIME = 0;
    int d[101];
    int f[101];
    int num;
    int graph[101][101] = {0};
 
void dfs(int x){
    TIME++;
    d[x] = TIME;
 
    for(int i=1;i<=num;i++){
        if(graph[x][i] == 1 && d[i]==0){
            dfs(i);
        }
    }
    f[x] = ++TIME;
}
 
int main(){
    int hon;
    int eda;
    int ver;
 
    cin>>num;
    for(int i=0;i<num;i++){
        cin>>eda;
        cin>>hon;
        for(int j=0;j<hon;j++){
            cin>>ver;
            graph[eda][ver]++;
        }
    }
     
    for(int i=1;i<=num;i++){
        if(d[i]==0)
            dfs(i);
    }
 
    for(int i=1;i<=num;i++){
        cout<<i<<" "<<d[i]<<" "<<f[i]<<endl;
    }
 
    return 0;
}