Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

type TimeRecord struct {
	discoverTime int
	finishTime   int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	timeRecordMap := make([]TimeRecord, n)
	childrenMap := make([][]int, n)
	for i := 1; i <= n; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		timeRecordMap[node-1] = TimeRecord{-1, -1}

		childNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		childrenMap[node-1] = make([]int, childNum)
		for j := 0; j < childNum; j++ {
			child, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			childrenMap[node-1][j] = child
		}
	}

	// TODO: always start with 1?
	timer := 1
	visit(1, &timer, childrenMap, timeRecordMap)
	for k, v := range timeRecordMap {
		fmt.Printf("%d %d %d\n", k+1, v.discoverTime, v.finishTime)
	}
}

func visit(currentNode int, timer *int, childrenMap [][]int, timeRecordMap []TimeRecord) {
	if timeRecordMap[currentNode-1].discoverTime > 0 {
		return
	}
	children := childrenMap[currentNode-1]
	timeRecordMap[currentNode-1] = TimeRecord{*timer, timeRecordMap[currentNode-1].finishTime}
	(*timer)++
	for i := 0; i < len(children); i++ {
		visit(children[i], timer, childrenMap, timeRecordMap)
	}
	timeRecordMap[currentNode-1] = TimeRecord{timeRecordMap[currentNode-1].discoverTime, *timer}
	(*timer)++
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

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

using namespace std; 

int Time;
vector< vector<int> > adj;
vector< pair<int,int> > res;

void dfs(int v) {
	res[v].first = Time;
	for (int i = 0; i < adj[v].size(); ++i) {
		if (res[adj[v][i]].first < 0) {
			++Time;
			dfs(adj[v][i]);
		}
	}
	++Time;
	res[v].second = Time;
	return;
}

int main(void) {
	int nov,noe,u,v;
	cin >> nov;
	adj = vector< vector<int> >(nov);
	for (int i = 0; i < nov; ++i) {
		cin >> u;
		cin >> noe;
		adj[u-1] = vector<int>(noe);
		for (int j = 0; j < noe; ++j) {
			cin >> adj[u-1][j];
			--adj[u-1][j];
		}
	}
	Time = 1;
	res = vector< pair<int,int> >(nov,{-1,-1});
	int start = 0;
	while (start >= 0) {
		dfs(start);
		start = -1;
		++Time;
		for (int i = 0; start < 0 && i < nov; ++i) {
			if (res[i].first < 0) {
				start = i;
			}
		}
	}
	for (int i = 0; i < nov; ++i) {
		cout << i+1 << " ";
		cout << res[i].first << " ";
		cout << res[i].second << endl;
	}
	return 0;
}

C++: #include <iostream>
using namespace std;
int v[101][101];
int node[101][2];
int t=1;
int n;
void dfs(int i){
   
    node[i][0]=t;
    t++;
    for(int i=1;i<=n;i++){
        v[i][1]=0;
    }
    for(int j=1;j<=n;j++){
        if(v[i][j]==1){
            for(int k=1;k<=n;k++){
                v[k][j]=0;
            }
            dfs(j);
        }
    }
    node[i][1]=t;
    t++;
}
int main(void){
    
    cin >> n;
    int x,y,z;
    for(int i=1;i<=n;i++){
        cin >> x>>y;
        for(int j=1;j<=y;j++){
            cin >> z;
            v[i][z]=1;
        }
    }
    dfs(1);
    
   for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            if(v[i][j]==1){
                dfs(i);
            }
        }
    }
    for(int i=1;i<=n;i++){
        cout <<i<< " " <<node[i][0]<<" " <<node[i][1]<<endl;
    }
   
    
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define repR(i, n) for(int i = (n) - 1; i > -1; i--)
#define rep1(i, n) for(int i = 1; i < (int)(n + 1); i++)
#define rep1R(i, n) for(int i = (n); i > 0; i--)
using namespace std;

const int WHITE = 0;
const int GRAY = 1;
const int BLACK = 2;

int n;
int M[110][110] = {};
int color[110];
int elapse = 0;
int d[110];
int f[110];

void dfs(int u) {
  color[u] = GRAY;
  d[u] = ++elapse;
  rep(v, n) {
    if (M[u][v] && color[v] == WHITE) dfs(v);
  }
  color[u] = BLACK;
  f[u] = ++elapse;
}

void dfs_init() {
  rep(i, n) color[i] = WHITE;
  dfs(0);
}

int main() {
  cin >> n;
  rep(i, n) {
    int id, deg;
    cin >> id >> deg;
    --id;    // 0-indexedに直す
    rep(j, deg) {
      int v;
      cin >> v;
      --v;    // 0-indexedに直す
      ++M[id][v];
    }
  }
  dfs_init();
  rep(i, n) {
    cout << i + 1 << " " << d[i] << " " << f[i] << endl;
  }
  return 0;
}

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

C++: #define _USE_MATH_DEFINES
#include <bits/stdc++.h>
#define int long long
#define rep(i,n) for(int i=0;i<n;i++)
#define Rep(i,a,b) for(int i=a;i<b;i++)
#define REP(i,a,b) for(int i=a;i<=b;i++)
#define rev(i,n) for(int i=n-1;i>=0;i--)
#define vi vector<int>
#define pb push_back
#define pi pair<int,int>
#define vp vector<pair<int,int>>
#define mp make_pair
#define all(v) (v).begin(),(v).end()
#define fi first
#define se second
#define MEMSET(a) memset(a,0,sizeof(a))
#define inf (1ll<<60)

using namespace std;

const int mod=1e9+7;

void run();

void init() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout<<fixed<<setprecision(12);
}

signed main(){
    init();
    run();
    return 0;
}

int d[101],f[101],t;

void dfs(vector<vi> a,int v){
    if(d[v])return;
    d[v]=++t;
    rep(i,a[v].size()){
        dfs(a,a[v][i]);
    }
    f[v]=++t;
}

void run(){
    int n;
    cin>>n;
    vector<vi> a(n+1);
    REP(i,1,n){
        int u,k;
        cin>>u>>k;
        rep(j,k){
            int v;
            cin>>v;
            a[u].pb(v);
        }
        sort(all(a[u]));
    }
    REP(i,1,n){
        dfs(a,i);
    }
    REP(i,1,n){
        cout<<i<<" "<<d[i]<<" "<<f[i]<<endl;
    }
}