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++: #if 0
以前の反省を踏まえて、idの扱いを早いうちに決めてよかった
#endif

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

int curtime = 0, INF = 10000 * 100000 + 100;
struct result
{
    int reach_time;
    int back_time;
};
result res[110];
struct nodeData
{
    int id;
    vector<int> nodes;
};
vector<nodeData> dataSet;

// idはは1から
// for文は1から回す
vector<int> getNodes(int id)
{
    return dataSet[id - 1].nodes;
}

void dfs(int cur)
{
    // curの訪問時刻を記録
    curtime += 1;
    res[cur].reach_time = curtime;
    vector<int> nodes = getNodes(cur);
    for (int i = 0; i < nodes.size(); i++)
    {
        int node = nodes[i];
        if (res[node].reach_time == INF)
        {
            // 未訪問の場合
            dfs(node);
        }
    }
    curtime += 1;
    res[cur].back_time = curtime;
}

int main()
{
    // 初期化
    int /* 頂点数 */ n;
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        nodeData temp;
        temp.id = i;
        int id, /* 出次数 */ appear;
        cin >> id >> appear;
        for (int j = 1; j <= appear; j++)
        {
            int node;
            cin >> node;
            temp.nodes.push_back(node);
        }
        dataSet.push_back(temp);
        res[i].reach_time = INF;
    }

    // 処理
    for (int i = 1; i <= n; i++)
    {
        if (res[i].reach_time == INF)
        {
            dfs(i);
        }
    }
    for (int i = 1; i <= n; i++)
    {
        cout << i << " " << res[i].reach_time << " " << res[i].back_time << endl;
    }
}

C++: #include<iostream>
#include<cstdio>
#define MAX_N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
using namespace std;

int n, u, k, v;
int Adj[MAX_N][MAX_N];
int d[MAX_N], f[MAX_N], color[MAX_N];
int tt;

void initialize(){
	for(int i = 0; i < n; i++){
		for(int j = 0; j < n; j++){
			Adj[i][j] = 0;
		}
	}
}

void check_adj(){
	Adj[u][v] = 1;
}

void dfs_visit(int u){
	color[u] = GRAY;
	d[u] = ++tt;
	for(int v = 0; v < n; v++){
		if(Adj[u][v] == 0) continue;
		if(color[v] == WHITE){
			dfs_visit(v);
		}
	}
	color[u] = BLACK;
	f[u] = ++tt;
}

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

/* void print_adj(){
	for(int i = 0; i < n; i++){
		for(int j = 0; j < n; j++){
			cout << Adj[i][j];
			if(j == n - 1) cout << endl;
			else cout << " ";
		}
	}
} */

int main(void){
	cin >> n;
	initialize();
	for(int i = 0; i < n; i++){
		cin >> u;
		u--;
		cin >> k;
		for(int j = 0; j < k; j++){
			cin >> v;
			v--;
			check_adj();
		}
	}
	dfs();
	//print_adj();

	return 0;
}

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

#define INPUT_FROM_FILE (0) 
#if INPUT_FROM_FILE
#include <fstream>
#endif

int time_stamp = 0;
std::vector<int> d;
std::vector<int> f;

void dfs(std::vector<std::vector<int> > &G, std::vector<bool> &is_searched, int i){
	if(is_searched[i]){
		//time++;
		return;
	}
	is_searched[i] = true;
	time_stamp++;
	d[i] = time_stamp;

	for(int j = 0; j < G[i].size(); j++){
		dfs(G, is_searched, G[i][j]);
	}
	time_stamp++;
	f[i] = time_stamp;
	return;
}

int main(int argc, char **argv){
	int n, u, k, v;
	std::vector<std::vector<int> > G;
	std::vector<bool> is_searched;

#if INPUT_FROM_FILE
	std::ifstream ifs("test.txt");
	//FILE *fp = fopen("test.txt", "r");
#endif

#if INPUT_FROM_FILE
	ifs >> n;
#else
	std::cin >> n;
#endif

	G.resize(n);
	is_searched.resize(n, false);
	d.resize(n, 0);
	f.resize(n, 0);
	for(int i = 0; i < n; i++){
#if INPUT_FROM_FILE
		ifs >> u >> k;
#else
		std::cin >> u >> k;
#endif
		G[u - 1].resize(k);
		for(int j = 0; j < k; j++){
#if INPUT_FROM_FILE
			ifs >> v;
#else
			std::cin >> v;
#endif
			G[u - 1][j] = v - 1;
		}
	}

	for(int i = 0; i < n; i++){
		dfs(G, is_searched, i);
	}

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

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

//次の点へ移動とかする関数
int next_point(int point, int (&a)[100][100], int (&num)[100], int (&back)[100], int time[100][2]){
	int next = a[point][num[point]]-1;
	
	//行先が探索終了しているしている場合、pointを返す
	if(a[next][1] == 0 && time[next][1] != 0){
		a[point][1] -= 1;
		return point;
	}
	
	back[next] = point;
	a[point][1] -= 1;
	return next;
}

int main(void){
	int a[100][100];
	int back[100];				//back[]:現在いる点の始点
	int time[100][2];	//time[i][0]:発見時刻,time[i][1]:探索終了時間
	int m, time_now=1, point=0;	//point:現在探索している点
	int num[100];
	
	cin >> m;
	
	for(int i=0; i<m;i++){
		cin >> a[i][0];
		cin >> a[i][1];
		
		for(int j=2; j<a[i][1]+2; j++){
			cin >> a[i][j];
		}
	}

	//ここまで入力
	//ここから↓
	
	//numを2に初期化
	for(int i=0; i<100; i++){
		num[i] = 2;
		time[i][0] = INT_MAX;
	}
	
	time[0][1] = -1;
	
	time[point][0] = time_now++;
	while(time[0][1] == -1){
		
		//矢印が出ていない場合
		if(a[point][1] == 0){
			time[point][1] = time_now++;	//探索終了時刻を決定
			point = back[point];	//始点へ移動
		}
		
		//矢印が出ている場合
		if(a[point][1] != 0){
			point = next_point(point, a, num, back, time);
			num[back[point]] += 1;
			if(time[point][0] > time_now) time[point][0] = time_now++;	//探索開始時刻を決定
		}
	}
	
	//出力
	for(int i=0; i<m; i++){
		cout << i+1 << " " << time[i][0] << " " << time[i][1] << "\n";
	}
	
	return 0;
}