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>
#define MAX 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
using namespace std;

int color[MAX];
bool M[MAX][MAX];
int n;
int tt;
int d[MAX];
int f[MAX];

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

void dfs_init() {
	for (int i = 0; i < n; i++) {
		color[i] = WHITE;
	}
	tt = 0;
	for (int u = 0; u < n; u++) {
		if (color[u] == WHITE) {
			dfs(u);
		}
	}
	for (int u = 0; u < n; u++) {
		cout << u + 1 << " ";
		cout << d[u] << " " << f[u] << endl;
	}
}

int main()
{
	cin >> n;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			M[i][j] = false;
		}
		d[i] = f[i] = 0;
	}
	for (int i = 0; i < n; i++) {
		int u, k, v;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			cin >> v;
			M[u - 1][v - 1] = true;
		}
	}
	
	dfs_init();

	return 0;
}

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

static const int N = 101;

using namespace std;

vector<vector<int> > V;
int d[N], f[N];
int step = 1;

void dfs (int v) {
  if (d[v])
    return;

  d[v] = step++;

  for (vector<int>::iterator it = V[v].begin(); it != V[v].end(); it++) {
    if (!d[*it]) {
      dfs(*it);
    }
  }

  f[v] = step++;
}

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

int main () {
  int n, v, v2, k;
  // stack<int> S;
  // vector<vector<int> > V;

  for (int i = 0; i <= N; i++) {
    vector<int> A;
    V.push_back(A);
  }
  for (int i = 0; i <= N; i++)
    d[i] = f[i] = 0;

  cin >> n;

  for (int i = 0; i < n; i++) {
    cin >> v >> k;

    for (int j = 0; j < k; j++) {
      cin >> v2;
      V[v].push_back(v2);
    }
  }

  // for (int i = 1; i <= n; i++) {
  //   for (int j = 1; j <= n; j++)
  //     cout << V[i][j] << (j == n ? "" : " ");
  //   cout << endl;
  // }

  // int step = 1;
  // bool breaked = false;

  // S.push(1);
  // d[S.top()] = step++;

  // while (S.size()) {
  //   // cout << "S.top = " << S.top() << endl;
  //   breaked = false;

  //   for (vector<int>::iterator it = V[S.top()].begin(); it != V[S.top()].end(); it++) {
  //     if (!d[*it]) {
  //       d[*it] = step++;
  //       S.push(*it);
  //       breaked = true;
  //       break;
  //     }
  //   }

  //   if (!breaked) {
  //     f[S.top()] = step++;
  //     S.pop();

  //     if (S.empty()) {
  //       for (int i = 1; i <= n; i++) {
  //         if (!d[i]) {
  //           S.push(i);
  //           d[i] = step++;
  //           break;
  //         }
  //       }
  //     }
  //   }
  // }

  dfs_init(n);

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

  return 0;
}

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

void dfs(vector<int> &discover, vector<int> &finished, vector<vector<bool>> &g, int n, vector<int> &color, int &time, int u){
    color[u]++;
    discover[u] = ++time;
    for (int i = 0; i < n; i++){
        if (g[u][i]){
            if (color[i] == 0){
                dfs(discover, finished, g, n, color, time, i);
            }
        }
    }
    color[u]++;
    finished[u] = ++time;
}

int main(){
    int n, u, k;
    int time = 0;
    cin >> n;
    vector<int> discover(n);
    vector<int> finished(n);
    vector<int> color(n, 0);
    vector<vector<bool>> g(n, vector<bool>(n, false));
    for (int i = 0; i < n; i++){
        cin >> u >> k;
        u--;
        int v;
        for (int j = 0; j < k; j++){
            cin >> v;
            v--;
            g[u][v] = true;
        }
    }

    for (int j = 0; j < n; j++){
        if (!color[j]){
            dfs(discover, finished, g, n, color, time, j);
        }
    }

    for (int i = 0; i < n; i++)
        cout << i + 1 << ' ' << discover[i] << ' ' << finished[i] << endl;
    return 0;
}

C++: #include <iostream>
#include <stack>
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];
int color[N], d[N], f[N], tt;
int nt[N];


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] = GREY;
	d[r] = ++tt;

	while (!S.empty()) {
		int u = S.top();
		int v = next(u);
		if (v != -1) {
			if (color[v] == WHITE) {
				color[v] = GREY;
				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 = 0; 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;
}