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
		}
	}

	timer := 1
	for {
		startNode := findStartNode(childrenMap, timeRecordMap)
		if startNode > 0 {
			visit(startNode, &timer, childrenMap, timeRecordMap)
		} else {
			break
		}
	}
	for k, v := range timeRecordMap {
		fmt.Printf("%d %d %d\n", k+1, v.discoverTime, v.finishTime)
	}
}

func findStartNode(childrenMap [][]int, timeRecordMap []TimeRecord) int {
	x := -1
	for node, timeRecord := range timeRecordMap {
		if timeRecord.discoverTime < 0 {
			x = node + 1
			break
		}
	}
	if x < 0 {
		return -1
	}

	found := false
	i := 0
	for i < len(childrenMap) {
		children := childrenMap[i]
		for j := 0; j < len(children); j++ {
			if children[j] == x {
				x = j + 1
				found = true
				break
			}
		}
		if found {
			i = 0
		} else {
			i++
		}
	}
	return x
}

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;

vector<bool> seen;
vector<int> fo;
vector<int> lo;
void dfs(vector<vector<int>> &g,int v,int& fp,int& lp){
    if(fo[v]==0)fo[v]=fp++;
    seen[v]=true;
    for(auto next:g[v]){
        if(seen[next])continue;
        dfs(g,next,fp,lp);
    }
    if(lo[v]==0)lo[v]=fp++;
}

int main(){
    int n;
    cin>>n;
    vector<vector<int>> g(n);
    int u,k,v;
    for(int i=0;i<n;i++){
        cin>>u>>k;
        if(k==0)continue;
        for(int j=0;j<k;j++){
            cin>>v;
            if(u==v)continue;
            g[u-1].push_back(v-1);
        }
    }

    seen.assign(n,false);
    fo.resize(n);
    lo.resize(n);
    int fp=1,lp=n+1;
    //dfs(g,0,fp,lp);
    for(int i=0;i<n;i++)dfs(g,i,fp,lp);

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

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

const long N = 100;
const long WHITE = 0;
const long GRAY = 1;
const long BLACK = 2;

long n, M[N + 1][N + 1];
long color[N + 1], d[N + 1], f[N + 1], tt;
long nt[N + 1];

long next(long u){
	for (long v = nt[u]; v < n; v++){
		nt[u] = v;
		if (M[u][v]) return v;
	}
	return -1;
}

void dfs_visit(long r){
	for (long i = 1; i <= n; i++) nt[i] = 0;

	stack<long> S;
	S.push(r);
	color[r] = GRAY;
	d[r] = ++tt;

	while (!S.empty()){
		long u = S.top();
		long 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 (long i = 1; i <= n; i++){
		color[i] = WHITE;
		nt[i] = 0;
	}
	tt = 0;

	for (long u = 1; u <= n; u++){
		if (color[u] == WHITE) dfs_visit(u);
	}
	for (long i = 1; i <= n; i++){
		cout << i << " " << d[i] << " " << f[i] << endl;
	}
}

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

	for (long i = 1; i <= n; i++){
		cin >> u >> k;
		for (long j = 1; j <= k; j++){
			cin >> v;
			M[u][v] = 1;
		}
	}

	dfs();

	return 0;
}

C++: #include <bits/stdc++.h>
#define MAX 100
using namespace std;

int n;
int t;
vector<int> G[MAX];
bool used[MAX];
int start[MAX];
int finish[MAX];

void DFS(int s) {
	if (used[s]) return;
	used[s] = true;
	start[s] = t++;
	for (int &v : G[s]) {
		DFS(v);
	}
	finish[s] = t++;
}

int main()
{
	cin >> n;
	for (int i = 0, u, k; i < n; i++) {
		cin >> u >> k;
		for (int j = 0, v; j < k; j++) {
			cin >> v;
			G[u - 1].push_back(v - 1);
		}
	}
	t = 1;
	DFS(0);
	for (int i = 0; i < n; i++) {
		cout << i + 1 << ' ' << start[i] << ' ' << finish[i] << endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>

#define FOR(i, a, b) for(long long int i=(a);i<=(b);i++)
#define RFOR(i, a, b) for(long long int i=(a);i>=(b);i--)
#define MOD 1000000007
#define INF 1000000000 //2000000000
#define LLINF 1000000000000000000 //9000000000000000000
#define PI 3.14159265358979

using namespace std;
typedef long long int ll;
typedef pair< long long int, long long  int> P;

int n;
int u, k, v;
int hour = 1;
int d[101] = {}, f[101] = {};
int gra[101][101] = {};
int color[101] = {};




void dfs(int u) {
	color[u] = 1;
	d[u] = hour;
	hour++;
	FOR(i, 1, n) {
		if (gra[u][i] == 1 && color[i] == 0) {
			dfs(i);
		}
	}
	color[u] = 2;
	f[u] = hour;
	hour++;
}

void dfs_call(void) {

	FOR(i, 1, n) {
		if (color[i] == 0) {
			dfs(i);
		}
	}
}


int main(void) {
	cin >> n;
	
	FOR(i, 1, n) {
		cin >> u >> k;
		FOR(t, 1, k) {
			cin >> v;
			gra[u][v] = 1;
		}
	}
	d[1] = hour;

	dfs_call();

	FOR(i, 1, n) {
		cout << i << " " << d[i] << " " << f[i] << endl;
	}

	return 0;
}

C++: #include <iostream>
using namespace std;
static const int N=100;
static const int WHITE=0;
static const int GRAY=1;
static const int BLACK=2;

int M[N][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(int i=0;i<n;i++){
		color[i]=WHITE;
	}
	tt=0;
	
	for(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 k,u,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;
}