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)
	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 <bits/stdc++.h>

using namespace std;

const int N = 105;

int n, k, u, v, clok;
int d[N], f[N], mark[N];
vector<int> a[N];

void DFS(int p)
{
  mark[p] = 1;
  d[p] = clok;
  clok++;
  for(int i = 0; i < a[p].size(); i++)
    if(!mark[a[p][i]]){
      DFS(a[p][i]);
    }
  f[p] = clok;
  clok++;
}

int main()
{
  cin >> n;
  for(int i = 1; i <= n; i++){
    cin >> u >> k;
    for(int j = 1; j <= k; j++) {
      cin >> v;
      a[u].push_back(v);
    }
    sort(a[u].begin(), a[u].end());
  }
  clok = 1;
  for(int i = 1; i <= n; i++)
    if(!mark[i]) DFS(i);
  for(int i = 1; i <= n; i++){
    cout << i << " " << d[i] << " " << f[i] << endl;
  }
  return 0;
}

C++: #include <bits/stdc++.h>
#define int long long
#define rng(i, l, r) for (size_t i = (l); i < (r); ++i)
#define rep(i, n) rng(i, 0, n)
#define gnr(i, l, r) for (size_t i = (r)-1; i >= (l); i--)
#define per(i, b) gnr(i, 0, b)
#define ALL(obj) (obj).begin(), (obj).end()    //1,2,3,...
#define rALL(obj) (obj).rbegin(), (obj).rend() //...,3,2,1

using namespace std;
const int INF = 1e18;

struct edge
{
    int to;
    int cost;
};
using Graph = vector<vector<edge>>;

#define WHITE 0
#define GRAY 1
#define BLACK 2

int n;
Graph G;

int seen[110];
int discover[110];
int finish[110];
int stamp = 0;

void dfs(int cur)
{
    discover[cur] = stamp++;

    seen[cur] = BLACK;
    for (auto ne : G[cur])
    {
        int v = ne.to;
        int vc = ne.cost;
        if (seen[v] == BLACK)
            continue;
        dfs(v);
    }

    finish[cur] = stamp++;
}

void solve()
{

    // remove the bottom 3 lines when you submit this code.
    std::ifstream in("sample.txt");
    std::cin.rdbuf(in.rdbuf());

    cin.tie(0);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;
    G.resize(n + 1);

    for (int i = 0; i <= n; i++)
    {
        if (i == 0)
        {
            for (int j = 1; j <= n; j++)
            {
                G[0].push_back((edge){j, 1});
            }
        }
        else
        {
            int u, k;
            cin >> u >> k;
            for (int j = 0; j < k; j++)
            {
                int v;
                cin >> v;
                G[u].push_back((edge){v, 1});
            }
        }
    }

    for (int i = 0; i < 110; i++)
    {
        seen[i] = WHITE;
        discover[i] = INF;
        finish[i] = INF;
    }

    dfs(0);

    for (int i = 1; i <= n; i++)
    {
        cout << i << " " << discover[i] << " " << finish[i] << endl;
    }
}

signed main()
{
    solve();
    return 0;
}

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

int n, t;
int v[100][100];
int d[100], f[100];

void stamp(int id) {
//	if (t > 2 * n)
//		return;
	
	if (d[id - 1] == 0) {
		d[id - 1] = t;
		t++;
		int i = 0;
		while (v[id - 1][i] == 0)
			i++;
		if (i < n && d[i] == 0)
			stamp(i + 1);
		else
			stamp(id);
	}
	else if (f[id - 1] == 0) {
		int i;
		for(i = n - 1; i > -1; i--)
			if (v[id - 1][i] == 1 && d[i] == 0)
				stamp(i + 1);
		if (i < 0 && f[id - 1] == 0) {
			f[id - 1] = t;
			t++;
			for (i = n - 1; i > -1; i--)
				if (v[i][id - 1] == 1 && f[i] == 0)
					stamp(i + 1);
		}
	}
	else
		return;
}

int main()
{
	cin >> n;

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

	for (int i = 0; i < n; i++)
		for (int j = 0; j < n; j++)
			v[i][j] = 0;

	for (int i = 0; i < n; i++) {
		int u, k, s;

		cin >> u >> k;

		for (int j = 0; j < k; j++) {
			cin >> s;
			v[u - 1][s - 1] = 1;
		}
	}

	t = 1;
	stamp(1);

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

	return 0;
}

C++: #include <stdio.h>
#include <iostream>
#include <algorithm>
#include <math.h>
#include <stack>

using namespace std;

int common_time=1,n;

int table[101][101],time_table[101][2];

void func(int node){
	if(time_table[node][0] == 0){
		time_table[node][0] = common_time++;
	}else{
		return;
	}
	for(int i=1;i<=n;i++){
		if(table[node][i] == 1){
			func(i);
		}
	}
	time_table[node][1] = common_time++;
}

int main(){
	int row,num,col;
	scanf("%d",&n);

	for(int i=1;i<=n;i++){
		for(int k=1;k<=n;k++){
			table[i][k]=0;
		}
		time_table[i][0]=0;
		time_table[i][1]=0;
	}

	for(int i=1;i<=n;i++){
		scanf("%d %d",&row,&num);
		for(int k=1;k<=num;k++){
			scanf("%d",&col);
			table[row][col]=1;
		}
	}

	for(int i=1;i<=n;i++){
		func(i);
	}

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

    return 0;
}

C++: #include <iostream>
#define MAX 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

using namespace std;

int n, t = 0;
int color[MAX+1];
int m[MAX+1][MAX+1];
int d[MAX+1], f[MAX+1];

void visit(int u){
    int v;
    color[u] = GRAY;
    d[u] = ++t;
    for(v = 1; v <= n; v++){
        if(m[u][v] == 0) continue;
        if(color[v] == WHITE) visit(v);
    }
    color[u] = BLACK;
    f[u] = ++t;
}

void dfs(){
    int u, i;
    for(u = 1; u <= n; u++) color[u] = WHITE;
    for(u = 1; u <= n; u++){
        if(color[u] == WHITE) visit(u);
    }
}

int main(){
    int k, u, v, i, j;
    
    cin >> n;

    for(i = 1; i <= n; i++){
        for(j = 1; j <= n; j++) m[i][j] = 0;
    }

    for(i = 1; i <= n; i++){
        cin >> u >> k;
        for(j = 1; j <= k; j++){
            cin >> v;
            m[u][v] = 1;
        }
    }

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