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<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;
}

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

enum Status {WHITE, GRAY, BLACK};

stack<int> stc;
Status *status;
int *discovered, *finished;
bool *visited;
vector<vector<int> > a;
int n, timer;

void dfs(int i){
        if(status[i]==BLACK) return;
        if(status[i]==WHITE){
                discovered[i] = ++timer;
                status[i] = GRAY;
        }

        if(visited[i]) return;
        visited[i] = true;
        stc.push(i);

        for(int j=0;j<a[i].size();j++) dfs(a[i][j]);

        if(status[i]==GRAY){
                finished[i] = ++timer;
                status[i] = BLACK;
        }
        stc.pop();
}

int main(){

        cin>>n;
        a = vector<vector<int> >(n, vector<int>());
        status = new Status[n];
        discovered = new int[n];
        finished = new int[n];
        visited = new bool[n];

        int m, k, r;
        for(int i=0;i<n;i++){
                cin>>r;
                cin>>m;
                for(int j=0;j<m;j++){
                        cin>>k;
                        a[r-1].emplace_back(k-1);
                }
        }
        for(int i=0;i<n;i++) status[i] = WHITE;
        for(int i=0;i<n;i++) visited[i] = false;

        timer = 0;
        for(int i=0;i<n;i++)
                dfs(i);

        for(int i=0;i<n;i++){
                cout<<i+1<<" "<<discovered[i]<<" "<<finished[i]<<endl;
        }
        return 0;
}

C++: #include "bits/stdc++.h"
using namespace std;
int main()
{
    int n, ti = 0;
    scanf("%d", &n);
    vector<vector<int>> a(n);
    vector<int> vis(n, 0), lea(n, 0), sea(n, 0);
    for (int i = 0, u, k; i < n; i++)
    {
        scanf("%d %d", &u, &k);
        u--;
        for (int j = 0, v; j < k; j++)
        {
            scanf("%d", &v);
            v--;
            a[u].push_back(v);
        }
    }
    for (int i = 0; i < n; i++)
    {
        if (!vis[i])
        {
            stack<int> b;
            b.push(i);
            for (int t; !b.empty(); )
            {
                t = b.top();
                if (!vis[t])
                {
                    vis[t] = ++ti;
                }
                for (; sea[t] < a[t].size(); sea[t]++)
                {
                    if (!vis[a[t][sea[t]]])
                    {
                        b.push(a[t][sea[t]]);
                        break;
                    }
                }
                if (sea[t] >= a[t].size())
                {
                    b.pop();
                    lea[t] = ++ti;
                }
            }
        }
    }
    for (int i = 0; i < n; i++)
    {
        printf("%d %d %d\n", i + 1, vis[i], lea[i]);
    }
}