Go: package main

import "fmt"

type node struct {
	id, d, v int
	adj      []node
}

var n int
var seen []bool
var graph []node

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func dfs(v, t int) int {
	// fmt.Printf("dfs(v %d, t %d) en:\n", v, t)
	seen[v] = true
	graph[v].v = t
	tt := t
	for _, vv := range graph[v].adj {
		if !seen[vv.id] {
			tt = max(tt, dfs(vv.id, tt+1))
		}
	}
	graph[v].d = tt + 1
	// fmt.Printf("dfs(v %d, t %d) ex: d %d\n", v, t, graph[v].d)
	return graph[v].d
}

func main() {
	fmt.Scan(&n)
	graph = make([]node, n+1)
	for i := 1; i <= n; i++ {
		var u, k, v int
		fmt.Scan(&u, &k)
		graph[u].id = u
		// 頂点uはk個の隣接頂点を持っている
		for j := 0; j < k; j++ {
			fmt.Scan(&v)
			var t node
			t.id = v
			graph[u].adj = append(graph[u].adj, t)
		}
	}
	// fmt.Println("n", n, "graph", graph)
	seen = make([]bool, n+1)
	// t := dfs(1, 1)
	v, t := 1, 1
	done := false
	for !done {
		tt := dfs(v, t)
		done = true
		for i := range seen {
			if !seen[i] {
				done = false
				v = graph[i].id
				t = tt
				break
			}
		}
	}
	for i := 1; i <= n; i++ {
		fmt.Printf("%d %d %d\n", i, graph[i].v, graph[i].d)
	}
}

C++: #include<iostream>
#include<vector>
#include<string>
#include<stack>
#include<cstdio>
#include<algorithm>
#define WHITE 0
#define GRAY 1
#define BLACK 2
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

int n, m[100][100] = { 0 }, d[100] = { 0 }, t = 0, nt[100] = { 0 }, f[100] = { 0 };
int color[100] = { WHITE };

int next(int u) {
	FOR(i, nt[u], n) {
		nt[u] = i + 1;
		if (m[u][i]==1){ return i; }
	}
	return -1;
}

int dfs(int r) {
	stack<int>S;
	S.push(r);
	color[r] = GRAY;
	d[r] = ++t;

	while (!S.empty()) {
		int u=S.top();
		int v = next(u); //cout << v << endl;
		if (v != -1) {
			if (color[v]==WHITE)
			{
				S.push(v);
				color[v] = GRAY;
				d[v] = ++t;
			}
		}
		else {
			S.pop();
			color[v] = BLACK;
			f[u] = ++t;
		//	cout << f[v]<<endl;
		}
	}
	return 0;
}
int main()
{
	 cin >> n;
	REP(i, n) {
		int u, k; cin >>u >> k; u--;//
		REP(j, k) {
			int muki; cin >> muki; muki--;//
			m[u][muki] = 1;
			//printf("%d aa%d\n", u, muki);
		}
	}
	REP(i, n) {
		if (color[i] == WHITE) {
			dfs(i);// cout << i << endl;
		}
	}
	REP(i, n) {
		cout << i + 1 << " " << d[i] << " " << f[i] << endl;
	}
	return 0;
}

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

using namespace std;

typedef vector<int> vec;
typedef vector<vec> Graph;

Graph G(110);
int T,In[110],Out[110];
bool used[110];

void dfs(int x)
{
	used[x]=true;
	In[x]=++T;
	for(int i=0;i<G[x].size();i++)
		if(!used[G[x][i]])
			dfs(G[x][i]);
	Out[x]=++T;
}

int main()
{
	int n;
	scanf("%d",&n);
	for(int i=0;i<n;i++)
	{
		int u,t;
		scanf("%d%d",&u,&t);
		for(int j=0;j<t;j++)
		{
			int v;
			scanf("%d",&v);
			G[u].push_back(v);
		}
	}
	memset(used,false,sizeof(used));
	T=0;
	for(int i=1;i<=n;i++)
		if(!used[i])
			dfs(i);
	for(int i=1;i<=n;i++)
		printf("%d %d %d\n",i,In[i],Out[i]);
	return 0;
}

C++: #include <iostream>
#include <cmath>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
#include <algorithm>

typedef long long ll;

using namespace std;

int t = 0;
vector<vector<int> > a;
vector<int> d, f;
vector<bool> v;

void dfs(int i) {
  v[i] = true;
  d[i] = ++t;
  for (int j : a[i]) {
    if (!v[j]) {
      dfs(j);
    }
  }
  f[i] = ++t;
}

int main() {
    int n; cin >> n;
    a.resize(n);
    for (int i = 0; i < n; i++) {
        int u; cin >> u; u--;
        int k; cin >> k;
        for (int j = 0; j < k; j++) {
            int v; cin >> v; v--;
            a[i].push_back(v);
        }

    }
    v.resize(n, false);
    d.resize(n);
    f.resize(n);

    for (int i = 0; i < n; i++) {
        if (!v[i]) {
            dfs(i);
        }
    }

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

C++: #define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <stdio.h>
#include <list>
#define black 0
#define red 1
#define white -1
#define maxn 110
using namespace std;

int tot = 0;
int book[maxn] = {}, t[maxn][2] = {};
list<int> map[maxn];

void dfs(int u)
{
	book[u] = red;
			t[u][0] = ++tot;
			for (list<int>::iterator it = map[u].begin(); it != map[u].end(); it++)
			{
				if (book[*it - 1] == black)
				{
					dfs(*it - 1);
				}
			}
			book[u] = white;
			t[u][1] = ++tot;
	return;
}
int main()
{
	int n;
	scanf("%d", &n);
	for (int i = 0; i < n; i++)
	{
		int u, k, v;
		scanf("%d%d", &u, &k);
		u--;
		for (int i = 0; i < k; i++)
		{
			scanf("%d", &v);
			map[u].push_back(v);
		}
	}
	for (int i = 0; i < n; i++)
		if (book[i] == black)
			dfs(i);
	for (int i = 0; i < n; i++)
	{
		printf("%d %d %d\n", i + 1, t[i][0], t[i][1]);;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define REP(i, n) for(int i = 0; i < n; i++)
#define REPR(i, n) for(int i = n - 1; i >= 0; i--)
#define FOR(i, m, n) for(int i = m; i < n; i++)
#define FORR(i,m,n) for(int i = m - 1; i >= n; i--)
#define ALL(v) v.begin(), v.end()
#define CMAX(m, x)  m = max(m,x)
#define CMIN(m, x)  m = min(m,x)
#define itn int
#define Yes() cout << "Yes" << endl
#define No() cout << "No" << endl
#define YES() cout << "YES" << endl
#define NO() cout << "NO" << endl
typedef long long lint;
typedef long double ldouble;
const int INF = 1e9;
const lint LINF = 1e18;

int cnt = 0;
void dfs(int i,vector<vector<int>> &g, vector<vector<int>> &ans){
    if(ans[i][0] == 0){
        cnt++; 
        ans[i][0] = cnt;
        REP(j,g[i].size()){
            dfs(g[i][j] - 1,g,ans);  
        }
        cnt++;

        ans[i][1] = cnt;
    }
}
int main(){
    int n;
    cin >> n;
    int u,k;
    vector<vector<int>> g(n);
    vector<vector<int>> ans(n,vector<int>(2,0));
    REP(i,n){
        cin >> u >> k;
        g[u - 1] = vector<int>(k);
        REP(j,k)
            cin >> g[u - 1][j];
    }
    REP(i,n)
        dfs(i,g,ans);
    REP(i,n){
        printf("%d %d %d\n",i + 1, ans[i][0],ans[i][1]);
    }

    return 0;
}

C++: #include <iostream>
#include <string>
#include <map>
#include <stack>
#include <algorithm>
using namespace std;
#define MAX 100000

static const int N=100;
static const int WHITE=0;
static const int GRAY=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]=GRAY;
  d[r]=++tt;
  while( !S.empty() ){
    int u=S.top();
    int v=next(u);
    if(v!=-1){
      if(color[v]==WHITE){
        color[v]=GRAY;
        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;
}