Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

type vertexId int

type vertex struct {
	id vertexId
	firstVisitAt int
	finishVisitAt int
	adjs []vertexId
}

func createVertex(id int, adjsInt []int) vertex {
	adjs := make([]vertexId, len(adjsInt))
	for i := 0; i < len(adjs); i++ {
		adjs[i] = vertexId(adjsInt[i])
	}
	return vertex{
		id: vertexId(id),
		firstVisitAt: 0,
		finishVisitAt: 0,
		adjs: adjs,
	}
}

func (v *vertex) doesAllAdjsVisited(vertices []vertex) bool {
	for _, vId := range v.adjs {
		adj := vertices[vId-1]
		if !adj.isVisited() {
			return false
		}
	}
	return true
}

func (v *vertex) isFirstVisit() bool {
	return v.firstVisitAt == 0
}

func (v *vertex) isVisited() bool {
	return v.firstVisitAt > 0
}

func (v *vertex) nextVertex(vertices []vertex) (vertexId, error) {
	for _, vId := range v.adjs {
		adj := vertices[vId-1]
		if !adj.isVisited() {
			return vId, nil
		}
	}
	return vertexId(-1), fmt.Errorf("illegal")
}

func dfs(currentId vertexId, timestamp int, vertices []vertex) int {
	timestamp = timestamp + 1
	currentVertex := &vertices[currentId-1]
	if currentVertex.isFirstVisit() {
		currentVertex.firstVisitAt = timestamp
	}
	for !currentVertex.doesAllAdjsVisited(vertices) {
		nextVertexId, _ := currentVertex.nextVertex(vertices)
		timestamp = dfs(nextVertexId, timestamp, vertices)
	}
	timestamp = timestamp + 1
	currentVertex.finishVisitAt = timestamp
	return timestamp
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	vertices := make([]vertex, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjN, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjs := make([]int, adjN)
		for j := 0; j < adjN; j++ {
			adjId, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			adjs[j] = adjId
		}
		vertices[i] = createVertex(id, adjs)
	}

	dfs(vertexId(1), 0, vertices)

	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", vertices[i].id, vertices[i].firstVisitAt, vertices[i].finishVisitAt)
	}
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func nextInt(sc *bufio.Scanner) (int, error) {
	return strconv.Atoi(nextText(sc))
}

C++: #include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

int	dfs(const Graph &graph,
		vector<int> &d_vec, vector<int> &f_vec, int u, int cur_time)
{
	d_vec.at(u) = ++cur_time;
	for (int v : graph.at(u)) {
		if (d_vec.at(v) != -1)
			continue;
		cur_time = dfs(graph, d_vec, f_vec, v, cur_time);
	}
	f_vec.at(u) = ++cur_time;
	return cur_time;
}	
		
int	main()
{
	int	n;
	cin >> n;
	Graph graph(n);
	vector<int>	d_vec(n, -1);
	vector<int>	f_vec(n, -1);
	int	k;
	int	u, v;
	for (int i = 0; i < n; ++i) {
		cin >> u >> k;
		--u;
		for (int j = 0; j < k; ++j) {
			cin >> v;
			--v;
			graph.at(u).push_back(v);
		}
	}
	int cur_time = 0;
	for (int i = 0; i < n; ++i) {
		if (d_vec.at(i) != -1)
			continue;
		cur_time = dfs(graph, d_vec, f_vec, i, cur_time);
	}
	for (int i = 0; i < n; ++i) {
		cout << i + 1 << " " << d_vec.at(i) << " " << f_vec.at(i) << endl;
	}
}

C++: #include<iostream>
#include<cstdio>
const int MAX=100;
const int WHITE=0;
const int GRAY=1;
const int BLACK=2;
using namespace std;
int M[MAX][MAX],d[MAX],f[MAX],tt,n,color[MAX];

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





void dfs(){
    int i;
    for(i=0;i<n;i++){
        color[i]=0;
    }
    tt=0;
    for(i=0;i<n;i++){
        if( color[i]==WHITE)dfs_visit(i);
    }
    for(i=0;i<n;i++){
        cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
    }
}
int main(){
  //  cout<<"A"<<endl;
    cin>>n;
    int u,v,k;
    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;
}

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

using namespace std;

const int MAX = 101;

vector<int> G[MAX];
int d[MAX], f[MAX];
int *T;

void dfs(int u) {

    if (!d[u]) d[u] = ++(*T);

    for (int v : G[u]) {
        if (!d[v]) d[v] = ++(*T);
        dfs(v);
    }

    if (!f[u]) f[u] = ++(*T);
}

int main() {

    int n;
    cin >> n;

    int t = 0;
    T = &t;
    fill(d, d + MAX, 0);
    fill(f, f + MAX, 0);

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

    for (int i = 1; i <= n; i++) {
        if (!d[i]) dfs(i);
    }


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

C++: #include <iostream>
#include <map>
#include <vector>

using namespace std;
struct node {
    node() {};
    node(int i, int n, int* xs) : id {i}, ns {vector<int>(xs, xs+n)} {
        delete xs;
    };
    int id;
    vector<int> ns;
    int in_time;
    int out_time;
};

int dfs(map<int, node*> graph, int time, int id){
    node* n = graph[id];
    if(n->in_time > 0){
        return time;
    }
    n->in_time = ++time;
    vector<int> ns = n->ns;
    for(auto it = ns.begin(); it != ns.end(); ++it){
        time = dfs(graph, time, *it);
    }
    n->out_time = ++time;
    return time;
}

int main(){
    int n;
    cin >> n;
    map<int, node*> graph {};
    int st = 1000000000;
    for(int i = 0; i < n; ++i){
        int id;
        cin >> id;
        st = min(st, id);
        int k;
        cin >> k;
        int* ns = new int[k];
        for(int j = 0; j < k; ++j){
            cin >> ns[j];
        }
        graph[id] = new node(id, k, ns);
    }
    int time = 0;
    for(auto it = graph.begin(); it != graph.end(); ++it){
        pair<int, node*> p = *it;
        if(p.second->in_time){
            continue;
        }
        time = dfs(graph, time, p.first);
    }
    for(auto it = graph.begin(); it != graph.end(); ++it){
        pair<int, node*> p = *it;
        cout << p.first << ' ' << p.second->in_time << ' ' << p.second->out_time << endl;
    }
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
#define WHITE 0
#define GRAY 1
#define BLACK 2
vector<vector<int>> M(100, vector<int>(100));
vector<int> C(100);
int n, tt;
vector<int> ST(100), PT(100);

int next(int u) {
  rep(i, n) {
    if (M.at(u).at(i) == 1 && C.at(i) == WHITE) {
      return i;
    }
  }
  return -1;
}

void dfs_visit(int u) {
  stack<int> S;
  S.push(u);
  ST.at(u) = ++tt;
  C.at(u) = GRAY;
  while (S.size() > 0) {
    int t = S.top();
    int v = next(t);
    if (v!=-1) {
      if (C.at(v) == WHITE) {
        S.push(v);
        ST.at(v) = ++tt;
        C.at(v) = GRAY;
      }
    } else {
      S.pop();
      PT.at(t) = ++tt;
      C.at(t) = BLACK;
    }
  }
}

void dfs() {
  tt = 0;
  rep(u, n) if (C.at(u) == WHITE) dfs_visit(u);
}

int main() {
  cin >> n;
  rep(i, n) {
    int id, k; cin >> id >> k;
    rep(j, k) {
      int num; cin >> num;
      M.at(id-1).at(num-1) = 1;
    }
  }
  dfs();

  rep(i,n) cout << i+1 << " " << ST.at(i) << " " << PT.at(i) << endl;
  return 0;
}