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

func dfs(currentId vertexId, timestamp int, vertices []vertex) int {
	currentVertex := &vertices[currentId-1]
	if currentVertex.isVisited() {
		return timestamp
	}
	timestamp = timestamp + 1
	currentVertex.firstVisitAt = timestamp
	for _, adjId := range currentVertex.adjs {
		timestamp = dfs(adjId, timestamp, vertices)
	}
	timestamp = timestamp + 1
	currentVertex.finishVisitAt = timestamp
	return timestamp
}

func solveDfs(vertices []vertex) {
	timestamp := 0
	for {
		vid := vertexId(-1)
		for i := 0; i < len(vertices); i++ {
			if !vertices[i].isVisited() {
				vid = vertexId(i+1)
				break
			}
		}
		if vid > 0 {
			timestamp = dfs(vid, timestamp, vertices)
		} else {
			break
		}
	}
}

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)
	}

	solveDfs(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>
using namespace std;
int g[101][102],ch[101][2]={0},kh;

int dfs(int k,int n){
  ch[n][0]=k;
  //cout<<k<<n<<"<--"<<endl;/////////
  for(int i=1;i<=g[n][0];i++){
    if(ch[g[n][i]][0]==0){
      k=dfs(k+1,g[n][i]);
    }
  }
  ch[n][1]=k+1;
  kh=k+1;
  return k+1;
}

int main(){
  int a,b,c,d;
  cin>>a;
  for(int i=0;i<a;i++){
    cin>>b>>c;
    g[b][0]=c;
    for(int j=1;j<=c;j++){
      cin>>d;
      g[b][j]=d;
    }
  }
  kh=0;
  for(int i=1;i<=a;i++){
    if(ch[i][0]==0){
      //cout<<i<<"<--"<<endl;////////
      dfs(kh+1,i);
    }
  }
  
  for(int i=1;i<=a;i++){
    cout<<i<<" "<<ch[i][0]<<" "<<ch[i][1]<<endl;
    
  }
  return 0;
}

C++: #include <iostream>
using namespace std;
struct Node{
  int u;
  int k;
  int v[99];

  int start;
  int finish;
};

int deep(Node nod[],int x,int count){
  if(nod[x].start)
    return count;

  nod[x].start=(++count);
  cout << nod[x].u << " " << count << endl;
  for(int i=0; i<nod[x].k; i++)
    count = deep(nod,nod[x].v[i]-1,count);

  nod[x].finish= (++count);
  return count;
}

int main(){
  int n,count=0;
  Node nod[100];

  cin >> n;
  for(int i=0; i<n; i++){
    cin >> nod[i].u >> nod[i].k;
    
    for(int j=0; j<nod[i].k; j++)
      cin >> nod[i].v[j];
    
    nod[i].start=0;
    nod[i].finish=0;
  }

  for(int i=0; i<n; i++)
    count = deep(nod,i,count);
  
  for(int i=0; i<n; i++){
    cout << nod[i].u << " " << nod[i].start << " " << nod[i].finish << endl;
  }
}

C++: #include <iostream>
#include <vector>
using namespace std;
typedef vector <int> vi;
typedef vector <vi> vvi;
int counter=0;

int addedge(vvi &graph, int y, int x, int val=1){
	graph[y][x] = val;
	return val;
}

int make_graph(vvi &graph, vvi &stamp){
	int n1=graph.size(), n2, row, col;

	for (int j=0; j<n1; j++){
		cin>>row;
		cin>>n2;
		for (int i=0; i<n2; i++){
			cin>>col;
			addedge(graph, row-1, col-1);
		}
		stamp[j][0] = -1;
	}
	return 0;
}

int Depth_First_Search(vvi &graph, vvi &stamp, int key=0){
	if (stamp[key][0] != -1) return 0;
	stamp[key][0] = ++counter;
	for (int i=0; i<int(graph[0].size()); i++){
		if (graph[key][i]==1 && stamp[i][0]==-1){
			Depth_First_Search(graph, stamp, i);
		}
	}
	stamp[key][1] = ++counter;
	return 0;
}

int resultout(vvi &stamp){
	for (int i=0; i<int(stamp.size()); i++){
		cout<<i+1<<" "<<stamp[i][0]<<" "<<stamp[i][1]<<endl;
	}
	return 0;
}

int main(void){

	int n, row;
	cin>>n;
	vvi G(n, vi(n)), stamp(n, vi(2));

	make_graph(G, stamp);

	Depth_First_Search(G, stamp);

	resultout(stamp);

	return 0;
}

C++: #include <iostream>

using namespace std;

const int N = 100;
int A[N][N] = {{0}};
int n;
int t = 0;
int d[N] = {0};
int f[N] = {0};

void dfs(int id) {
    if (d[id] != 0) {
        return;
    }
    ++t;
    d[id] = t;

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

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

int main() {
    cin >> n;
    for (int i = 0; i < n; ++i) {
        int u;
        cin >> u;

        int k;
        cin >> k;
        for (int j = 0; j < k; ++j) {
            int x;
            cin >> x;
            A[u-1][x-1] = 1;
        }
    }

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

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

    return 0;
}