Go: package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
)

const N = 100

const (
	WHITE = iota
	GRAY
	BLACK
)

type Graph struct {
	M               [N][N]int
	color, d, f, nt [N]int
	tt              int
}

func (g *Graph) next(u, n int) int {
	for v := g.nt[u]; v < n; v++ {
		g.nt[u] = v + 1
		if g.M[u][v] != 0 {
			return v
		}
	}
	return -1
}

func (g *Graph) dfsVisit(r, n int) {
	var S []int
	S = append([]int{r}, S...)
	g.color[r] = GRAY
	g.tt++
	g.d[r] = g.tt

	for len(S) != 0 {
		u := S[0]
		v := g.next(u, n)
		if v == -1 {
			S = S[1:]
			g.color[u] = BLACK
			g.tt++
			g.f[u] = g.tt
			continue
		}

		if g.color[v] != WHITE {
			continue
		}

		g.color[v] = GRAY
		g.tt++
		g.d[v] = g.tt
		S = append([]int{v}, S...)
	}
}

func (g *Graph) dfs(n int) string {
	for i := 0; i < n; i++ {
		g.color[i] = WHITE
	}
	g.tt = 0

	for u := 0; u < n; u++ {
		if g.color[u] == WHITE {
			g.dfsVisit(u, n)
		}
	}

	var out bytes.Buffer
	for i := 0; i < n; i++ {
		out.WriteString(fmt.Sprintf("%d %d %d\n", i+1, g.d[i], g.f[i]))
	}

	return strings.TrimRight(out.String(), "\n")
}

func answer(reader io.Reader) string {
	sc := bufio.NewScanner(reader)
	sc.Split(bufio.ScanWords)

	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())

	var g Graph
	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())
		u--
		for j := 0; j < k; j++ {
			sc.Scan()
			v, _ := strconv.Atoi(sc.Text())
			v--
			g.M[u][v] = 1
		}
	}

	return g.dfs(n)
}

func main() {
	fmt.Println(answer(os.Stdin))
}

C++: #include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cassert>
#include <string>
#include <cstring>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>

using namespace std;

// ---------------------
// repetition
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)

// debug
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

// ---------------------
#define INF 922337203685477580
typedef long long ll;

int matrix[110][110];
int d[110];
int f[110];
int n;
int elapsed = 1;

void visit(int v) {
  d[v] = elapsed++;

  FOR(i, 1, n + 1) {
    if (matrix[v][i] && d[i] < 0 ) {
      visit(i);
    }
  }
  f[v] = elapsed++;
}

int main() {
  REP(x, 110) {
    REP(y, 110) {
      matrix[x][y] = 0;
    }
    d[x] = -1;
    f[x] = -1;
  }

  // int n;
  cin >> n;

  REP(_, n) {
    int v, num;
    cin >> v >> num;

    REP(i, num) {
      int cv;
      cin >> cv;
      matrix[v][cv] = 1;
      // matrix[cv][v] = 1;
    }
  }


  FOR(v, 1, n + 1) {
    if (d[v] < 0) {
      visit(v);
    }
  }

  FOR(v, 1, n + 1) {
    cout << v << " " << d[v] << " " << f[v] << endl;
  }


  return 0;
}

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

int n;
int M[100][100];
int color[100], d[100], f[100];
int time;

void Dfs(int u) {
  color[u] = 1;
  d[u] = ++time;
  for (int v = 0; v < n; v++) if (M[u][v] && color[v] == 0) Dfs(v);
  color[u] = 2;
  f[u] = ++time;
}

int main() {
  cin >> n;

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

  Dfs(0);

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

  return 0;
}

C++: #include <iostream>
#include <stdio.h>
#define MAX 101
#define WHITE 0
#define GRAY 1
#define BLACK 2

int n, M[MAX][MAX];
int color[MAX];
int s_timer[MAX], b_timer[MAX], pass;

void dfs_search(int u) {
    int v;
    color[u] = GRAY;
    s_timer[u] = ++pass;
    for (v = 0; v < n; v++) {
        if (M[u][v] == 0) continue;
        if (color[v] == WHITE) {
            dfs_search(v);
        }
    }
    color[u] = BLACK;
    b_timer[u] = ++pass;
}

void dfs() {
    for (int i = 0; i < n; i++) {
        color[i] = WHITE;
    }
    pass = 0;
    
    for (int j = 0; j < n; j++) {
        if (color[j] == WHITE) dfs_search(j);
    }
    
    for (int t = 0; t < n; t++) {
        printf("%d %d %d\n", t+1, s_timer[t], b_timer[t]);
    }
}

int main() {
    int u, k, v;
    scanf("%d", &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++) {
        scanf("%d %d", &u, &k);
        u--;
        if (k == 0) continue;
        for (int j = 0; j < k; j++) {
            scanf("%d", &v);
            v--;
            M[u][v] = 1;
        }
    }
    
    dfs();
    
    return 0;
}

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

int visit[100],end[100],a[100][100];
int t,N,u,k,col;

void rist_to_mat(int N) {
	for(int l=0; l<N; ++l) {
		cin >> u >> k;
		for (int i=0; i<k; ++i) {
			cin >> col;
			a[u-1][col-1] = 1;
		}
	}
}

void dfs(int cur,int N) {
	t += 1;
	visit[cur] = t;
	for(int dst=0; dst<N; ++dst) {
		if(a[cur][dst] == 1 && visit[dst] == 0) {
			dfs(dst,N);
		}
	}
	t += 1;
	end[cur] = t;
}

int main() {
	cin >> N;
	rist_to_mat(N);
	dfs(0,N);
	for(int i=0; i<N; ++i) {
		cout << i+1 << ' ' << visit[i] << ' ' << end[i] << endl;
	}
}

C++: #include <iostream>
#include <iomanip>
#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <functional>
#include <sstream>
#include <string>
#include <utility>
#include <map>
#include <memory>
#include <set>
#include <vector>
#include <deque>
#include <list>
#include <stack>
#include <queue>

using namespace std;

class DFS
{
public:
  int n;
  int solve();
  int dfs( int v, int t, vector<vector<int>>& adj, vector<int>& d, vector<int>& f );
};

int DFS::dfs( int v, int t, vector<vector<int>>& adj, vector<int>& d, vector<int>& f )
{
  if ( d[v] )
    return t;
  else
    d[v] = t++;

  for ( auto i = 1; i <= n; ++i )
    if ( adj[v][i] )
      t = dfs( i, t, adj, d, f );

  f[v] = t;

  return ++t;
}

int DFS::solve()
{
  cin >> n;

  vector<vector<int>> adj(n+1, vector<int>(n+1, 0));
  vector<int> d(n+1,0);
  vector<int> f(n+1,0);

  for ( auto i = 0; i < n; ++i )
    {
      int x, k;
      cin >> x;
      cin >> k;
      for ( auto j = 0; j < k; ++j )
        {
          int y;
          cin >> y;
          adj[x][y] = 1;
        }
    }

  dfs( 1, 1, adj, d, f );

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

int main()
{
  DFS d;

  d.solve();

  return 0;
}

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

using namespace std;

#define Vi vector<int>
#define FOR(i,s,e) for (int i=s; i<e; i++)
#define ITER(v) v.begin(), v.end()

constexpr int N_MAX = 100;

int adj_matrix[N_MAX+1][N_MAX+1];

int d[N_MAX+1];
int f[N_MAX+1];

stack<int> route;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;

    int id, k, v;
    FOR(i,0,n) {
        cin >> id;
        cin >> k;
        FOR(j,0,k) {
            cin >> v;
            adj_matrix[id][v] = 1;
        }
    }

    const int TIMELIMIT = 2 * n;

    int cur = 1;
    route.push(0);
    route.push(0);

    FOR(t,1,TIMELIMIT) {
        if (!d[cur]) {
            d[cur] = t;
            //cout << t << " " << cur << " start" << endl;
        }
        int next = 0;
        FOR(i,1,n+1) {
            if (adj_matrix[cur][i] && !d[i]) {
                next = i;
                break;
            }
        }
        if (next == 0) {
            f[cur] = t + 1;
            cur = route.top();
            route.pop();
            //cout << t << " " << cur << " back" << endl;
        } else {
            route.push(cur);
            cur = next;
            //cout << t << " " << cur << " next" << endl;
        }
    }

    FOR(i,1,n+1) {
        cout << i << " " << d[i] << " " << f[i] << endl;
    }

    return 0;
}