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 <iostream>
#include <vector>

using namespace std;
static const int MAX=101;
bool Visited[MAX]; //??\?????????????¢??????????
vector<int> Adjacency[MAX];
int dTime[MAX]; int fTime[MAX]; //?¢??????°??¶??´????¢?????????¶??´
void dfs(int i,int& clock) //??¶????????°?????\???????????¨
{
    clock++;
    Visited[i]=true;
    dTime[i]=clock; //???????????°??¶??´
    for(int j=0;j<Adjacency[i].size();j++)
    {
        if(Visited[Adjacency[i][j]]==true) continue;
        dfs(Adjacency[i][j],clock);
    }
    clock++; //???????????????????¢????
    fTime[i]=clock;
}

int main()
{
    int n;
    cin>>n;
    for(int i=1;i<=n;i++) Visited[i]=false;

    for(int i=1;i<=n;i++)
    {
        int p;cin>>p;
        int num;
        cin>>num;

        for(int j=0;j<num;j++)
        {
            int t;
            cin>>t;
            Adjacency[p].push_back(t);
        }
    }
    int clock=0;
    dfs(1,clock);
    for(int i=1;i<=n;i++)
        cout<<i<<' '<<dTime[i]<<' '<<fTime[i]<<endl;
}

C++: #include<iostream>

int d[101]={0};
int f[101]={0};
int us[101]={0};
int V[101][101]={0};
int t=1;
int n;

void tansaku(int x)
{
  d[x]=t++;
  us[x]++;
  for(int i=0;i<n;i++){
    if(V[x][i]==1 and us[i]==0){
      tansaku(i);
    }
  }
  f[x]=t++;
}


int main()
{
  int n;
  int u,k,v;
  std::cin>>n;
  for(int i=0;i<n;i++){
    std::cin>>u>>k;
    for(int j=0;j<k;j++){
      std::cin>>v;
      V[u-1][v-1]=1;
    }
  }
  for(int i=0;i<n;i++){
    if(us[i]==0){
      tansaku(i);
    }
  }
  for(int i=0;i<n;i++){
    std::cout<<i+1<<" "<<d[i]<<" "<<f[i]<<"\n";
  }
  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define REP(i,n) for(int i=0; i<(n); i++)
#define REP2(i,x,n) for(int i=x; i<(n); i++)
#define PRINT(x) cout<<(x)<<endl
#define INF 1000000000000 // 10^12
#define MOD 1000000007 // 10^9+7
#define PB push_back
#define MP make_pair

const int MAX_N = 100, MAX_K = 100;

int n, u, k, v[MAX_K];

vector<int> G[MAX_N];
int d[MAX_N], f[MAX_N];
int t = 0;

void dfs(int);

int main() {
    // input
    cin >> n;
    REP(i, n) {
        cin >> u >> k;
        u--;
        REP(j, k) {
            cin >> v[j];
            v[j]--;
            G[u].PB(v[j]);
        }
    }

    // init d
    REP(i, n) d[i] = -1;

    // dfs
    REP(i, n) {
        if (d[i] == -1) dfs(i);
    }

    // output
    REP(i, n) {
        int id = i + 1;
        printf("%d %d %d\n", id, d[i], f[i]);
    }

    return 0;
}

void dfs(int pos) {
    d[pos] = ++t;
    REP(i, G[pos].size()) {
        int to = G[pos][i];
        if (d[to] != -1) continue;
        dfs(to);
    }
    f[pos] = ++t;
    return;
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define loop(i,a,b) for(i=a;i<b;i++)
#define rloop(i,a,b) for(i=a;i>=b;i--)
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
const int inf=1000000001;
const ll INF=1e16;
#define MOD 1000000007
#define mod 1000000009
#define pi 3.14159265358979323846
static const int WHITE=0;
static const int GRAY=1;
static const int BLACK=2;
static const int N=101;

int n,tt=0;
vii M(N,vi(N,0));
vi color(N,WHITE),d(N),f(N),nt(N,0);

void dfs();
void dfs_visit(int);
int next(int);

int main(){
	int i,j,u,k,v;
	cin>>n;
	loop(i,0,n){
		cin>>u>>k;
		loop(j,0,k){
			cin>>v;
			M[u][v]=1;
		}
	}
	dfs();
}

void dfs(){
	int i;
	loop(i,1,n+1){
		if(color[i]==WHITE){
			dfs_visit(i);
		}
	}
	loop(i,1,n+1){
		cout<<i<<" "<<d[i]<<" "<<f[i]<<endl;
	}
}

void dfs_visit(int r){
	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;
		}
	}
}

int next(int u){
	int v;
	loop(v,nt[u]+1,n+1){
		nt[u]=v;
		if(M[u][v]){
			return v;
		}
	}
	return -1;
}

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

using namespace std;
int timetime = 0;

void dfs(int cur, vector<vector <int> > &list, vector<int> &d, vector<int> &f) {
		d[cur] =timetime;
		timetime +=1;
    for(int i = 0; i < list.size();i++){
      vector<int>::iterator it = list[cur].end();
	  vector<int>::iterator hoge = find(list[cur].begin(),list[cur].end(),i);
      if(d[i] == 0 && (hoge != it ) ){
        dfs(i,list,d,f);
      }
    }
    f[cur] = timetime;
    timetime +=1;
}

int main() {
  int np;
  int k,t,x;
  cin >> np ;
 
  vector <vector <int> > list(np);
  for(int i = 0;i<np;i++) {
    cin >> k;
    cin >> t;
    for(int j = 0; j < t ;j++) {
      cin >>x;
      list[k-1].push_back(x-1);
    }
  }
  vector <int> d(np,0);
  vector <int> f(np,0);
  dfs(0,list,d,f);
  for(int i = 0;i < np; i++){
    cout << i+1 <<" "<<d[i]+1 <<" "<<f[i]+1<<endl;
  }


  return 0;
}