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;

int n;
vector<vector<int> > A;
vector<vector<int> > T;
int t = 0;

void dfs(int cur){ // cur????¨????
    // cur ????¨??????????????¨????
    t += 1;
    T[cur][0] = t;
    // ???????¢??????¨??¨???
    // cerr << "visiting " << cur << " " << t << endl;

    for(int dst = 0; dst < n; ++dst){ // ??¨???????????? dst ????????????
        if(A[cur][dst] == 1 && T[dst][0] == -1){ // cur??????dst??????????????????,dst???????¨??????????
            dfs(dst);
        }
    }
    // cur ????¨????????????????????¨????
    t += 1;
    T[cur][1] = t;
    // ??¢??°?????????????????????????????? (?????¢??°)
    return; // ?????\???
}

int main(){
    cin >> n;
    A = vector<vector<int> >(n, vector<int>(n, 0));
    T = vector<vector<int> >(n, vector<int>(2, -1));
    for(int i=0; i<n; ++i){
        int k;
        cin >> k;
        // 1~n???index?????¨????????????????????????????????????1????????????0~n-1????????????
        k -= 1;
        int u;
        cin >> u;
        for(int j=0; j<u; ++j){
            int v;
            cin >> v;
            v -= 1;
            A[k][v] = 1;
        }
    }
    for(int i=0; i<n; ++i){
        if(T[i][0] == -1){
          dfs(i);
        }
    }
    for(int i=0; i<n; ++i){
        cout << i+1 << " " << T[i][0] << " " << T[i][1] << endl;
    }
}

C++: #include <cstdio>

typedef struct{
	bool isVisited;
	int degree;
	int start;
	int end;
	int *neighbors;
} node;

int count = 1;

void dfs(node* nodes, int id){
	nodes[id].isVisited = true;
	if (nodes[id].start == 0) nodes[id].start=count;
	for (int i=0; i<nodes[id].degree; i++){
		if (!nodes[nodes[id].neighbors[i]].isVisited){
			count ++;
			dfs(nodes, nodes[id].neighbors[i]);
		}
	}
	count++;
	nodes[id].end = count;
}

int main(){
	int n, d, r, id;
	node *nodes;

	scanf("%d", &n);
	nodes = new node[n];
	for (int i=0; i<n;i++){
		nodes[i].isVisited=false;
		scanf("%d %d", &r, &d);
		nodes[i].degree=d;
		nodes[i].neighbors = new int[d];
		nodes[i].start = 0;
		
		for (int j=0;j<d;j++){
			scanf("%d", &id);
			nodes[i].neighbors[j] = id-1;
		}
	}

	dfs(nodes, 0);
	for (int i=0; i<n;i++){
		printf("%d %d %d\n", i, nodes[i].start, nodes[i].end);
		delete []nodes[i].neighbors;
	}
	delete []nodes;
	return 0;
}

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

using namespace std;

/*****************************************/
/*         Function prototype            */
/*****************************************/

vector<vector<int> > list_to_mat(vector<vector<int> >& adj);
void dump_mat( vector<vector<int> >& mat);
void dfs(vector<vector<int> >& adj_list, int now, vector<int>& d, vector<int>& f, int *t);

/*****************************************/
/*            Main Function              */
/*****************************************/


int main(){
  int n; cin >> n;

  vector<vector<int> > list(n+1);
  for(int i=0; i<n; i++){
    int u,k; cin >> u >> k;
    vector<int> tmp(k);
    for(int j=0; j<k; j++) cin >> tmp[j];
    sort(tmp.begin(),tmp.end());
    list[u] = tmp;
  }
  int t=1;
  vector<int> d(n+1,-1);
  vector<int> f(n+1,-1);

  dfs(list,1,d,f,&t);

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



/*****************************************/
/*            Implimentation             */
/*****************************************/


void dfs(vector<vector<int> >& adj_list, int now, vector<int>& d, vector<int>& f, int* t){
  d[now] = *t;
  (*t)++;
  
  for(auto v : adj_list[now]){
    if(d[v] != -1) continue;
    dfs(adj_list, v, d, f, t);
  }
  f[now] = *t;
  (*t)++;
  return ;
}


vector<vector<int> > list_to_mat(vector<vector<int> >& adj){
  const int mat_size = (int)adj.size();
  vector<vector<int> > ans(mat_size,vector<int>(mat_size,0));
  for(int i=0; i<mat_size; i++){
    for(int j=0; j<adj[i].size(); j++){
      ans[i][adj[i][j]-1] = 1;
    }
  }
  return ans;
}


void dump_mat( vector<vector<int> >& mat){
  
  const int mat_size = (int)mat.size();
  for(int i=0; i<mat_size; i++){
    for(int j=0; j<mat[i].size(); j++){
      cout << mat[i][j];
      if(j!=mat[i].size()-1)
	cout << " ";
      else
	cout << "\n";
    }
  }
}

C++: #include <stdio.h>
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

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] == WHITE) dfs_visit(v);
	}
	color[u] = BLACK;
	f[u] = ++tt;
}

void dfs(){
	int u;
	for (u = 0; u<n; u++) color[u] = WHITE;
	tt = 0;
	for (u = 0; u<n; u++)
		if (color[u] == WHITE) 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", &u, &k);
		u--;
		for (j = 0; j<k; j++){
			scanf("%d", &v);
			v--;
			M[u][v] = 1;
		}
	}
	dfs();
	return 0;
}