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 101
#define NIL -1
#define WHITE 0
#define GRAY 1
#define BLACK 2

int n, t, top, u[MAX], color[MAX], M[MAX][MAX], S[MAX], d[MAX], f[MAX];

int next(int u){
  for(int i=1; i<=n; i++){
    if(M[u][i] == 1 && color[i] == WHITE){
      return i;
    }
  }
  return NIL;
}

void dfs(int u){
  int v;
  S[++top] = u;
  color[u] = GRAY;
  d[u] = ++t;

  while(top > 0){
    u = S[top];
    v = next(u);
    if(v != NIL){
      color[v] = GRAY;
      d[v] = ++t;
      S[++top] = v;
    }else{
      top--;
      color[u] = BLACK;
      f[u] = ++t;
    }
  }
}

void dfs_init(){
  for(int i=0; i<MAX; i++){
    color[u[i]] = WHITE;
  }

  t = 0;
  top = 0;
}

int main(void){
  int k, m;
  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[i] >> k;
    for(int j=0; j<k; j++){
      cin >> m;
      M[u[i]][m] = 1;
    }
  }

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

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

C++: #include<bits/stdc++.h>
using namespace std;
int n,step=0,fdepth[105],sdepth[105];
bool visit[105],c[105][105];
void dfs(int node){
    step++;
    fdepth[node]=step;
    for(int i=1;i<=n;i++)
        if(!visit[i]&&c[node][i]){
            visit[i]=1;
            dfs(i);
        }
    step++;
    sdepth[node]=step;
}
int main(){
    ios_base::sync_with_stdio(0);
    //cin.tie(0);
    while(cin>>n){
        memset(fdepth,0,sizeof(fdepth));
        memset(sdepth,0,sizeof(sdepth));
        memset(c,0,sizeof(c));
        memset(visit,0,sizeof(visit));
        int parent,num,son;
        step=0;
        for(int i=0;i<n;i++){
            cin>>parent>>num;
            while(num--){
                cin>>son;
                c[parent][son]=1;
            }
        }
        visit[1]=1;
        dfs(1);
        for(int i=1;i<=n;i++)
            cout<<i<<' '<<fdepth[i]<<' '<<sdepth[i]<<'\n';
    }
    return 0;
}

C++: #include<bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int) (n); i++)
using namespace std;

#define MAX 100

int d[MAX], f[MAX], t = 0, M[MAX][MAX] = {}, n;

void dfs(){
    int seen[MAX] = {};
    rep(i, n){
        if(seen[i]) continue;
        stack<int> todo;
        seen[i] = 1;
        todo.push(i);
        t++;
        d[i] = t;
        while(!todo.empty()){
            int m = todo.top();
            rep(j, n + 1){
                if(j == n){
                    todo.pop();
                    t++;
                    f[m] = t;
                    break;
                }
                if(M[m][j] && !seen[j]){
                    todo.push(j);
                    t++;
                    d[j] = t;
                    seen[j] = 1;
                    break;
                }
            }
        }
    }
}

int main(){
    cin >> n;
    rep(i, n){
        int l, p;
        cin >> l >> p;
        rep(j, p){
            int q;
            cin >> q;
            M[l - 1][q - 1] = 1;
        }
    }
    dfs();
    
    rep(i, n){
        cout << i + 1 << " " << d[i] << " " << f[i] << endl;
    }
    
    return 0;
}