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<stack>
using namespace std;

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];

// uに隣接するvを番号順に取得
int next(int u){
    for(int v=nt[u]; v<n; v++){ // 訪問した場所は探索しなくていいため、v+1にしている？
        nt[u] = v+1;
        if(M[u][v]) return v;
    }
    return -1;
}

// スタックを用いた深さ優先探索
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(){
    // 初期化
    for(int i=0; i<n; i++){
        color[i] =WHITE;
        nt[i] = 0;
    }
    tt = 0;

    // 未訪問のuを始点として深さ優先探索
    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 argc, char const *argv[])
{
    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--; // 0 origin
        for(int j=0; j<k; j++){
            cin >> v;
            v--;
            M[u][v] = 1;
        }
    }

    dfs();

    return 0;
}

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

using namespace std;

int t;
int N;
int d[110], f[110];
vector<vector<int> > adj(110);
void dfs(int cur){
    d[cur] = t;
    t += 1;
    //cerr << "visiting " << cur << " " << t << endl;
    for(int i = 0; i < adj[cur].size(); ++i){
        int dst = adj[cur][i];
        if(d[dst] == 0){
            dfs(dst);
        }
    }
    f[cur] = t;
    t++;
}

int main(){
    cin >> N;
    t = 1;
    int u, k;
    for(int i = 0; i < N; ++i){
        cin >> u >> k;
        for(int j = 0; j < k; j++){
            int v;
            cin >> v;
            adj[u].push_back(v);
        }
        sort(adj[u].begin(), adj[u].end());
    }
    dfs(1);
    for(int i = 1; i < N+1; ++i){
        cout << 1 << " " << d[i] << " " << f[i] << endl;
    }
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
//#define ll long long
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }
#define rep(i, n) REP(i, 0, n)
#define rep_rev(i, n) for (int (i) = (int)(n) - 1 ; (i) >= 0 ; --(i))
#define ALL(v) v.begin(), v.end()
#define MSG(a) cout << #a << " " << a << endl;
#define REP(i, x, n) for(int i = x; i < n; i++)
#define all(x) (x).begin(),(x).end()
ll tmp1,tmp2,tmp3;
const ll mod = 1000000007;
const int INF = 1e9;
const ll INFLONG = 1e18;
void swap(ll *x,ll *y){
  ll tmp;
  tmp = *x;
  *x = *y;
  *y = tmp;
}
vector<ll> visited(100,0);
vector<ll> vec[100];
vector<ll> cou_l(100,0);
vector<ll> cou_f(100,0);
ll sum = 0;
void dfs(ll k){
  //cout << k << endl;
  if(visited[k]){return;}
  visited[k] = 1;
  sum++;
  cou_f[k] = sum;
  for(auto itr : vec[k]){
    //cout << itr << endl;
    dfs(itr);
  }
  sum++;
  cou_l[k] = sum;
}
int main(){
  ll n;
  cin >> n;
  ll u,k,v;
  rep(i,n){
    cin >> u >> k;
    u--;
    rep(j,k){
      cin >> v;
      v--;
      vec[u].push_back(v);
    }
  }
  rep(i,n){
    if(visited[i] == 0){
      dfs(i);
    }
  }
  rep(i,n){
    cout << i+1 << " " << cou_f[i] << " " << cou_l[i] << endl;
  }
}

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