Go: #include <bits/stdc++.h>
using namespace std;
static const int WHITE = 0;
static const int GRAY  = 1;
static const int BLACK = 2;
static const int N     = 100;

int n, tt;
vector<vector<int>> M(N, vector<int>(N));
vector<int> color(N), d(N), f(N);

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

void dfs() {
  tt = 0;

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

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

C++: /* ALDS1_11_B: Depth First Search */

#include <iostream>
#include <cstdio>
#include <vector>
using std::vector;

vector<int> *graph;
int elapsed = 1;

// Search the graph recursively by depth-first search.
void traverse(int id, int found[], int finished[]) {
    if (0 < found[id]) {
        return;
    }

    found[id] = elapsed++;
    vector<int> degrees = graph[id];
    for (int i = 0; i < degrees.size(); i++) {
        traverse(degrees[i], found, finished);
    }
    finished[id] = elapsed++;
}

int main() {
    int n_v;
    scanf("%d", &n_v);

    int max_v = n_v + 1;
    graph = new vector<int>[max_v];

    for (int i = 0; i < max_v; i++) {
        int id, n_degrees;
        scanf("%d %d", &id, &n_degrees);

        for (int j = 0; j < n_degrees; j++) {
            int deg_id;
            scanf("%d", &deg_id);
            graph[id].push_back(deg_id);
        }
    }

    int found[max_v];
    int finished[max_v];
    std::fill_n(found, max_v, 0);
    std::fill_n(finished, max_v, 0);

    traverse(1, found, finished);

    for (int id = 1; id < max_v; id++) {
        printf("%d %d %d\n", id, found[id], finished[id]);
    }
    return 0;
}

C++: //#include <bits/stdc++.h>
#include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <cmath>
#include <algorithm>
#include <map>
#include <iomanip>
#include <stdlib.h>
#include <stdio.h>
#include <queue>
#include <deque>
#include <set>
#include <stack>
#include <time.h>
 
using namespace std;
 
typedef long long ll;
typedef long double ld;
typedef pair<int, int> Pii;
typedef pair<int, ll> Pil;
typedef pair<ll, ll> Pll;
typedef pair<ll, int> Pli;
 
const ll MOD = 1e9 + 7;
const ll MOD2 = 998244353;
const ll INF = 1ll << 60;
const double PI = 2 * asin(1);

int N, Start[105], Goal[105];
vector <int> Graph[105];

int Time = 0;
int DFS(int node){
  for (int i = 0; i < Graph[node].size(); i++){
    int next = Graph[node][i];
    if (Start[next] == 0){
      Time++;
      Start[next] = Time;
      DFS(next);
    }
  }
  Time++;
  Goal[node] = Time;
  return 0;
}

int main(){
  cin >> N;
  for (int i = 0; i < N; i++){
    int M, K; cin >> M >> K;
    for (int j = 0; j < K; j++){
      int Node; cin >> Node;
      Graph[M].push_back(Node);
    }
  }

  for (int i = 1; i <= N; i++){
    if (Graph[i].size() > 0) sort(Graph[i].begin(), Graph[i].end());
  }
  
  for (int i = 1; i <= N; i++){
    if (Start[i] == 0){
      Time++; Start[i] = Time; DFS(i);
    }
  }
  

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

C++: #include<iostream>
#include<climits>
#include<vector>
#include<list>
#include<functional>
#include<algorithm>
#include<string>
#include<cmath>
#include<complex>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<tuple>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) for(int i=0;i<(n);i++)
#define INF (int)1e9
#define INFL (ll)1e11
using namespace std;
typedef long long ll;
typedef pair<int, int> P;

void dfs(int i, vector<vector<int>> a, vector<int> &d, vector<int> &f) {
	int n = a.size();
	int next = -1;
	REP(j, n) {
		if (d[j] == 0 && a[i][j]) {
			if (next == -1) d[j] = d[i] + 1;
			else d[j] = f[next] + 1;
			next = j;
			dfs(j, a, d, f);
		}
	}
	if (next == -1) f[i] = d[i] + 1;
	else f[i] = f[next] + 1;
}

void dfs_all(vector<vector<int>> a, vector<int> &d, vector<int> &f) {
	int i = 0;
	int n = a.size();
	int end = -1;
	while (1) {
		if (end == -1) d[0] = 1;
		else {
			while (d[i] > 0) i++;
			if (i == n) return;
			d[i] = f[end] + 1;
		}
		end = i;
		dfs(i, a, d, f);
	}
}

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

	int n;
	cin >> n;
	vector<vector<int>> a(n, vector<int>(n, 0));
	REP(i, n) {
		int u, k;
		cin >> u >> k;
		u--;
		REP(j, k) {
			int v;
			cin >> v;
			a[u][--v] = 1;
		}
	}
	vector<int> d(n + 1, 0);
	d[0] = 1;
	vector<int> f(n);
	dfs_all(a, d, f);
	
	REP(i, n) {
		cout << i + 1 << " " << d[i] << " " << f[i] << "\n";
	}

	return 0;
}

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

using namespace std;
#define MAX 105
vector<int> V[MAX];

int d[MAX], f[MAX];

int t;

void search(int v) {
	if (d[v] != 0)return;
	d[v] = t++;

	for (int i = 0; i < V[v].size(); i++) {
		search(V[v][i]);
	}
	f[v] = t++;
}

int main() {
	t = 1;
	int n;
	cin >> n;
	for (int i = 1; i < n + 1; i++) {
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			int s;
			cin >> s;
			V[u].push_back(s);
		}
	}
	for (int i = 1; i < n + 1; i++) {
		if (d[i] == 0)search(i);
	}
	for (int i = 1; i < n + 1; i++) {
		cout << i << ' ' << d[i] << ' ' << f[i] << endl;
	}

	return 0;
}

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

int m[101][101];
int visit[101];
int d[101];
int f[101];
int n, t;

void dfs(int u){
  visit[u] = 1;
  d[u] = t;
  t++;
  
  for(int i = 0; i < n; ++i){
    if(m[u][i] == 1 && visit[i] == 0){
      dfs(i);
    }
  }

  f[u] = t;
  t++;
}

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

  for(int i = 0; i < n; ++i){
    if(visit[i]==0){
      t=1;
      dfs(i);
    }
  }

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

  return (0);
}

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

typedef vector<vector<int>> Graph;

int N;
Graph G;
vector<int> td, tf;
int timestamp;

void dfs(int v){
	td[v] = timestamp++;

	for(int i=0; i<G[v].size(); i++){
		int u = G[v][i];
		if(td[u] == -1){
			dfs(u);
		}
	}

	tf[v] = timestamp++;
}

int main(){
	cin >> N;
	G.resize(N);
	td.resize(N, -1);
	tf.resize(N, -1);

	for(int i=0; i<N; i++){
		int x; cin >> x; x--;
		int k; cin >> k;
		for(int i=0; i<k; i++){
			int y; cin >> y; y--;
			G[x].push_back(y);
		}
	}

	timestamp = 1;
	dfs(0);

	for(int i=0; i<N; i++){
		cout << i+1 << " " << td[i] << " " << tf[i] << endl;
	}

	return 0;
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<stdio.h>
#include<cstring>
#include<math.h>
#include<map>
#include<bitset>
#include<iomanip>
using namespace std;

#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
int n;
int d[100] = {0};
int f[100] = {0};
bool m[100][100];
int t = 1;

void dfs(int x) {
  for(int i = 0; i < n; i++) {
    if(d[i] == 0) {
      if(m[x][i] == true) {
        d[i] = t;
        t++;
        dfs(i);
        f[i] = t;
        t++;
      } else if(x == i) {
        d[i] = t;
        t++;
        dfs(i);
        f[i] = t;
        t++;
      }
    }
  }
}

int main() {

  rep(i, n) {
    rep(j, n) {
      m[i][j] = false;
    } 
  }
  m[0][0] = true;
  // m[2][2] = true;

  cin >> n;
  for(int i = 0; i < n; i++) {
    int x, temp;
    cin >> x >> temp;
    for(int j = 0; j < temp; j++) {
      int y;
      cin >> y;
      m[x - 1][y - 1] = true;
    }
  }

  t = 1;
  rep(i, n) {
    // dfs(0);
    dfs(i);
    // if(d[i] == 0) dfs(i);
  }

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

  return 0;
}