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>

using namespace std;

#define MAX 100

int n,Time;
int G[MAX][MAX],d[MAX],f[MAX];
bool used[MAX];

void dfs(int v){
  d[v] = Time++;
  used[v] = true;

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

  f[v] = Time++;
}

int main(){
  cin >> n;

  for(int i = 0 ; i < n ; i++){
    int u,k,v;
    cin >> u >> k;
    for(int j = 0 ; j < k ; j++){
      cin >> v;
      G[u-1][v-1] = v-1;
    }
  }

  Time = 1;
  for(int i = 0 ; i < n ; i++){
    if(!used[i]){
      dfs(i);
    }
  }

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

  return 0;
}

C++: #include<queue>
#include<stack>
#include<string>
#include<iostream>
#include<algorithm>
using namespace std;
 
int n, dd[100], f[100], tmap[100][100];
int color[100], t = 1;
stack<int> S;
 
int a(){
    int d = S.top();
    dd[d] = t;
    t++;
    color[d] = 1;

    for (int i = 1; i <= n; i++){
        if (color[i] == 0 && tmap[d][i] == 1){
            S.push(i);
            a();
        }
    }

    f[d] = t;
    t++;
    return 0;
}
 
 
int main(){
    cin >> n;
    for (int i = 0; i < 100; i++){
        dd[i] = f[i] = color[i] = 0;
        for (int j = 0; j < 100; j++){
            tmap[i][j] = 0;
        }
    }
 
    int u, k, v;
 
    for (int i = 0; i < n; i++){
        cin >> u >> k;
        for (int j = 0; j < k; j++){
            cin >> v;
            tmap[u][v] = 1;
        }
    }
    for(int i=1;i<=n;i++){
        if(color[i] == 0){
             S.push(i);
             a();
         }
    }
    for (int i = 1; i <= n; i++){
        cout << i << " " << dd[i] << " " << f[i] << endl;
    }
    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;
}

C++: #include<iostream>
#include<stack>
#include<queue>
using namespace std;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

struct Node{
	int color, d, f;
	queue<int> Q;
};

int main(){
	int n;
	cin >> n;
	Node node[n + 1];
	stack<int> move;
	for(int i = 1; i <= n; i++){
		int u, k, v;
		cin >> u >> k;
		node[u].color = WHITE;
		while(k--){
			cin >> v;
			node[u].Q.push(v);
		}
	}

	move.push(1);
	int tt = 1, p, next;
	node[1].color = GRAY;
	node[1].d = tt;
	tt++;

	while(!move.empty()){
		p = move.top();
		if(node[p].Q.empty()){
			node[p].color = BLACK;
			node[p].f = tt;
			move.pop();
			tt++;
		} else {
			next = node[p].Q.front();
			if(node[next].color == WHITE){
				move.push(next);
				node[next].color == GRAY;
				node[next].d = tt;
				tt++;
			} else {
				node[p].Q.pop();
			}
		}
	}

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

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<vector>
#include<queue>
using namespace std;
 
int find_t[101],end_t[101];
vector<queue<int> > vec(101);
int flag[101];
int t=1;
 
void DFS(int);
void Print();
 
int main(int argc,char* argv[]){
  int n,id,cnt,x;
   
  memset(find_t,255,sizeof(find_t));
  memset(end_t,0,sizeof(end_t));
  memset(flag,0,sizeof(flag));
 
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>id>>cnt;
    flag[id]=0;
    queue<int> tmp;
    for(int l=0;l<cnt;l++){
      cin>>x;
      tmp.push(x);
    }
    vec[id]=tmp;
  }
   
  for(int i=1;i<=n;i++){
    if(flag[i]==0)
      DFS(i);
  }
  Print();
   
  return 0;
}
 
void DFS(int p){
  if(flag[p]==0){
    find_t[p]=t++;
    flag[p]=1;
  }
  else
    return;
     
  queue<int> tmp=vec[p];
  while(!tmp.empty()){
    DFS(tmp.front());
    tmp.pop();
  }
 
  end_t[p]=t++;
}
 
void Print(){
  for(int i=1;i<=100;i++){
    if(find_t[i]!=-1)
      printf("%d %d %d\n",i,find_t[i],end_t[i]);
  }
}