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<cstdio>
#include<iostream>
using namespace std;
int n, adj[101][101], d[101], f[101];
int visited[101]; int  tt=0;

void dfs_visit(int i)
{
  if(visited[i]) return ;
  visited[i] = 1;
  d[i] = ++tt;
  for(int v=1; v<=n; v++)
  {
    if(visited[v]==0 && adj[i][v]==1)
      dfs_visit(v);
  }
  f[i] = ++tt;
}
void dfs(int s)
{
  for(int i=1; i<=n; i++)
  {
    dfs_visit(i);
  }
}

int main()
{
  scanf("%d", &n);
  int u, k, v;
  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++)
  {
    scanf("%d%d", &u, &k);
    for(int j=0; j<k; j++)
    {
      scanf("%d", &v);
      adj[u][v] = 1;
    }
  }
  for(int i=0; i<=n; i++) visited[i] = 0;
  dfs(1);
  for(int i=1; i<=n; i++)
  {
    printf("%d %d %d\n", i, d[i], f[i]);
  }


  return 0;
}

C++: #include <cstdio>
#include <cstring>

const int MAX = 100;
static int time = 0;
int adj[MAX][MAX];
int discover[MAX];
int finish[MAX];

void visit(int node, int n)
{
  ++time;
  if (discover[node - 1] == 0)
    discover[node - 1] = time;

  for (int i = 0; i < n; ++i)
  {
    if (adj[node - 1][i] == 1 && finish[i] == 0)
      visit(i + 1, n);
  }

  ++time;
  finish[node - 1] = time;
}

int main()
{
  std::memset(adj, 0, sizeof(adj));
  std::memset(discover, 0, sizeof(discover));
  std::memset(finish, 0, sizeof(finish));

  int n;
  scanf("%d", &n);

  int u, k, v;
  for (int i = 0; i < n; ++i)
  {
    scanf("%d%d", &u, &k);
    for (int j = 0; j < k; ++j)
    {
      scanf("%d", &v);
      adj[u - 1][v - 1] = 1;
    }
  }

  visit(1, n);

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

  return 0;
}

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

typedef struct {
	bool endflag;
	int firsttime;
	int endtime;
}State;

const int Max = 100;
int map[Max + 1][Max + 1] = { 0 };
std::stack<int> st;
std::vector<State> state;


int main()
{
	int n, k, v, x;
	int cnt = 1;

	std::cin >> n;
	for (int i = 1; i <= n; i++) {
		std::cin >> x >> k;
		for (int j = 1; j <= k; j++) {
			std::cin >> v;
			map[x][v] = 1;
		}
	}

	State s = { false,0,0 };
	for (int i = 0; i <= n; i++) {
		state.push_back(s);
	}

	while (1) {
		if (st.empty() == true) {
			if (state[1].endflag == true) {
				break;
			}
			else {
				st.push(1);
				state[1].firsttime = cnt;
				cnt++;
				continue;
			}
		}

		bool flag = false;
		for (int i = 1; i <= n; i++) {
			if (map[st.top()][i] == 1) {
				if (state[i].endflag == false) {
					st.push(i);
					state[i].firsttime = cnt;
					cnt++;
					flag = true;
					break;
				}
			}
		}
		if (flag == true) {
			continue;
		}
		else {
			state[st.top()].endflag = true;
			state[st.top()].endtime = cnt;
			cnt++;
			st.pop();
		}
	}

	for (int i = 1; i <= n; i++) {
		std::cout << i << " " << state[i].firsttime << " " << state[i].endtime << std::endl;
	}

	return 0;
}

C++: #include <bits/stdc++.h>

#define M_PI       3.14159265358979323846   // pi

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<ll> VI;
typedef pair<ll, ll> P;
typedef tuple<ll, ll, ll> t3;
typedef tuple<ll, ll, ll, ll> t4;
typedef tuple<ll, ll, ll, ll, ll> t5;

#define rep(a,n) for(ll a = 0;a < n;a++)
#define repi(a,b,n) for(ll a = b;a < n;a++)

using namespace std;

static const ll INF = 1e15;

int main() {
	ll n;
	cin >> n;
	vector<vector<ll>> g(n);
	rep(i, n) {
		int a, k;
		cin >> a >> k;
		rep(j, k) {
			int t;
			cin >> t;
			t--;
			g[i].push_back(t);
		}
	}

	vector<bool> visit(n, false);

	vector<int> start(n);
	vector<int> finish(n);

	int t = 0;

	function<void(int)> dfs = [&](int current){
		if (visit[current]) return;
		visit[current] = true;
		t++;
		start[current] = t;
		for (auto p : g[current]) {
			dfs(p);
		}
		t++;
		finish[current] = t;
		return;
	};
	rep(i, n) {
		dfs(i);
	}
	rep(i, n) {
		cout << i + 1 << " " << start[i] << " " << finish[i] << endl;
	}
	return 0;
}

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

int n, M[N][N];
int color[N], s[N], f[N], ts; 

void dfs_visit(int u) {
    cout << u<< endl;
    int v;
    color[u] = GRAY;
    s[u] = ++ts;
    for (v=0; v<n; v++) {
        if(M[u][v]==0){
            continue;
        }
        if (color[v]==WHITE) {
            dfs_visit(v);
        }
    }
    color[u] = BLACK;
    f[u] = ++ts;
}

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

int main() {
    int u, k, tmp;
    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;
        for (int j=0; j<k; j++) {
            cin >> tmp;
            M[u-1][tmp-1] = 1;
        }
    }
    dfs();
    return 0;
}