Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	f         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []*DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]*DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes] = &DirectedGraphNode{}
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].f = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

var time = 0

func fillDistancesByDepthFirstSearch(g *DirectedGraph) {
	for _, u := range g.nodes[1:] {
		if !u.visited {
			dfsVisit(g, u)
		}
	}
}

func dfsVisit(g *DirectedGraph, u *DirectedGraphNode) {
	time++
	u.d = time

	u.visited = true
	for _, v := range u.adjacents {
		if !v.visited {
			v.parent = u
			dfsVisit(g, v)
		}
	}
	time++
	u.f = time
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	fillDistancesByDepthFirstSearch(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		fmt.Println(node.key, node.d, node.f)
	}
}

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

vector<int> G[102];
int d[102];
int f[102];
bool used[102];


int dfs(int i, int t){
    d[i] = t++;
    used[i] = true;
    for(vector<int>::iterator it = G[i].begin(); it != G[i].end(); ++it){
        if(!used[*it]){
            t = dfs(*it, t);
        }
    }
    
    f[i] = t++;
    return t;
}

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

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

vector<vector<int> > list(100);
vector<vector<int> > timed(100);
int times;
void dfs(int now){
	if(!timed[now].empty())	return;
	timed[now].push_back(times++);
	for(int i=0;i<(int)list[now].size();i++){
		dfs(list[now][i]);
	}
	timed[now].push_back(times++);
}

int main(){
	int n;	cin>>n;
	int id,num,ne;
	for(int i=0;i<n;i++){
		cin>>id>>num;
		id--;
		for(int j=0;j<num;j++){
			cin>>ne;
			list[id].push_back(ne-1);
		}
	}
	times=1;
	for(int i=0;i<n;i++){
		if(timed[i].empty())	dfs(0);
	}
	for(int i=0;i<n;i++){
		cout<<i+1;
		for(int j=0;j<(int)timed[i].size();j++){
			cout<<" "<<timed[i][j];
		}
		cout<<endl;
	}
	return 0;
}

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

int n, u, k, v;
int d[101], f[101];
pair<int, vector<int> > G[101];

int ti = 1;

void dfs(int id) {
	if (d[id]) return ;
	d[id] = ti ++;

	vector<int>& adj = G[id].second;
	for (int i=0; i<(int)adj.size(); ++i) {
		dfs(adj[i]);
	}
	f[id] = ti ++;
}

int main() {
	cin >> n;
	for (int i=0; i<n; ++i) {
		cin >> u >> k;
		G[u].first = u;
		while (k --) {
			cin >> v;
			G[u].second.push_back(v);
		}
	}
	for (int i=1; i<=n; ++i) {
		dfs(i);
		cout << i << " " << d[i] << " " << f[i] << endl;
	}
	return 0;
}

C++: #include <stdio.h>
#include <stdlib.h>

int stack[100], sp;
int start[100], end[100];
int ti;

void dfs(int , int **);
void visit(int , int **, int *);
int pop();
void push(int);

int main(){

  int i, j;
  int n, u , k;
  int **a;

  scanf("%d", &n);

  a = (int **)malloc(sizeof(int *) * n);

  for(i = 0; i < n; i++){
    scanf("%d%d", &u, &k);

    a[i] = (int *)malloc(sizeof(int) * k + 1);
    a[i][k] = -1;

    for(j = 0; j < k; j++){
      scanf("%d", &a[i][j]);
    }

  }

  dfs(n, a);

  for(i = 0; i < n; i++){
    printf("%d %d ", i + 1, start[i]);
    printf("%d\n", end[i]);
  }


  return 0;
}

void dfs(int n, int **a){

  int i;
  int color[100];

  for(i = 0; i < n; i++){
    color[i] = 0;
  }

  for(i = 0; i < n; i++){
    if(color[i] == 0) visit(i, a, color);
  }

}

void visit(int u, int **a, int *c){

  int i;
  int v;

  printf("%d\n", u);

  c[u] = 1;
  start[u] = ++ti;

  for(i = 0; a[u][i] != -1; i++){
    v = a[u][i] - 1;
    if(c[v] == 0) visit(v, a, c); 

  }  

  c[u] = 2;
  end[u] = ++ti;

}

int pop(){

  sp--;

  return stack[sp];
}


void push(int d){

  stack[sp] = d;

  sp++;

}

C++: #include<iostream>
#include<cstdio>
#define N 100
#define  GRAY 1
#define BLACK 2
using namespace std;
int n,M[N][N];
int color[N],d[N],f[N],tt;
void dfs_visit(int u)
{
  int v;
  color[u] = GRAY;
  d[u] = ++tt;
  for(v = 0;v<n;v++)
  {  
    if(M[u][v] == 0)
     continue;
  if(color[v] == 0)
    {
      dfs_visit(v);
    }
}
  color[u] = BLACK;
  f[u] == ++tt;
}
void dfs()
{
  int u;
  for(u = 0;u<n;u++)
     color[u] = 0;
  tt = 0;
  for(u = 0;u<n;u++)
  {
    if(color[u] == 0) dfs_visit(u);
  }
  for(u = 0;u<n;u++)
  {
    printf("%d %d %d\n",u+1,d[u],f[u]);
  }
}
int main ()
{
  int u,v,k,i,j;
  scanf("%d",&n);
  for( i = 0;i<n;i++)
  {  for( j = 0;j<n;j++)
        M[i][j] = 0; }
  for( i =0;i<n;i++)
   {
     scanf("%d %d",&n,&k);
     u--;
     for( j = 0;j<k;j++)
       {
         scanf("%d",&v);
         v--;
         M[u][v] = 1;
       }
   }
   dfs();
  return  0 ;
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;

int n,t;
int d[100],f[100];
bool graph[100][100], visited[100];

void dfs(int v){
    visited[v]=true;
    t++;
    d[v]=t;

    for(int v2=0; v2<n; v2++){
        if(graph[v][v2] && visited[v2]==false) dfs(v2);
    }

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

int main(void){
    cin >> n;
    t=0;

    for(int i=0; i<n; i++){
        for(int j=0; j<n; j++){
            graph[i][j]=false;
        }
    }
    for(int i=0; i<n; i++){
        int v,k; cin >> v >> k;
        for(int j=0; j<k; j++){
            int w; cin >> w;
            graph[v-1][w-1]=true;
        }
    }

    for(int i=0; i<n; i++) visited[i]=false;
    for(int i=0; i<n; i++){
        if(visited[i]==false) dfs(i);
    }
    for(int i=0; i<n; i++){
        printf("%d %d %d\n", i+1, d[i], f[i]);
    }
}