Go: package main

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

const MAX = 101

var f [MAX]int
var d [MAX]int
var list [][]int
var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func dfs(u, cnt int) int {
	if d[u] != 0 {
		return cnt
	}

	cnt++
	d[u] = cnt
	for _, next := range list[u] {
		cnt = dfs(next, cnt)
	}
	cnt++
	f[u] = cnt
	return cnt
}

func main() {
	n := scanInt()
	list = make([][]int, n+1)
	for i := 1; i <= n; i++ {
		u := scanInt()
		k := scanInt()
		for j := 0; j < k; j++ {
			n := scanInt()
			list[u] = append(list[u], n)
		}
	}

	cnt := 0
	for i := 1; i <= n; i++ {
		cnt = dfs(i, cnt)
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 1; i <= n; i++ {
		fmt.Fprint(w, i)
		fmt.Fprint(w, " ")
		fmt.Fprint(w, d[i])
		fmt.Fprint(w, " ")
		fmt.Fprint(w, f[i])
		fmt.Fprintln(w)
	}
	w.Flush()
}

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

using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)

typedef long long ll;
typedef pair<int, int> P;

#define MAX 100005
#define INF INT_MAX

int timeStamp = 0;
vector< vector<int> > adj;
vector<int> d, f;

void dfs(int v)
{
    d[v] = ++timeStamp;
    for (auto e : adj[v]) {
        if (d[e]) continue;
        dfs(e);
    }
    f[v] = ++timeStamp;
}

int main(int, char**)
{
    int n;
    cin >> n;

    adj.assign(n, vector<int>());
    d.assign(n,0);
    f.assign(n,0);
    int u, k, v;
    rep(i,n) {
        cin >> u >> k; u--;
        rep(j,k) {
            cin >> v; v--;
            adj[u].push_back(v);
        }
    }
    rep(i,n) {
        if (d[i]) continue;
        dfs(i);
    }
    rep(i,n) {
        cout << i+1 << " " << d[i] << " " << f[i] << endl;
    }
    return 0;
}

C++: #include <iostream>
#include<stdio.h>
#include<stack>

#define MAX 100
#define WHITE 1
#define GRAY 2
#define BLACK 3

using namespace std;

int color[MAX], d[MAX], f[MAX];
int n, A[MAX][MAX];
int tt;

void dfs_visit_1(int u) { //???????????°
    color[u] = GRAY;
    d[u] = ++tt;
    for(int v = 0; v < n; v++) {
        if(A[u][v] == 0) continue;
        if(color[v] == WHITE) dfs_visit_1(v);
    }
    color[u] = BLACK;
    f[u] = ++tt;
}

void dfs_1() { // ???????????°
    for(int i = 0; i < n; i++) {
        color[i] = WHITE;
    }
    tt = 0;
    for(int i = 0; i < n; i++) {
        if(color[i] == WHITE) dfs_visit_1(i);
    }

    for(int i = 0; i < n; i++) {
        printf("%d %d %d\n", i+1, d[i], f[i]);
    }

}

int next(int u) {
    for(int v = 0; v < n; v++) {
        if(A[u][v] == 1) {
            /*
            if(color[v] == WHITE) return v;
            else if(color[v] == BLACK) return -1;
            else if(color[v] == GRAY) continue;
            */
            return v;
        }
    }
    return -1;
}

void dfs_visit_2(int u) {
    color[u] = GRAY;
    d[u] = ++tt;
    stack<int> S;
    S.push(u);

    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;
        }
    }
}


int main()
{
    int u, k, v;
    scanf("%d",&n);

    for(int i = 0; i < n; i++) {
        scanf("%d%d", &u, &k);
        for(int j = 0; j < k; j++) {
            scanf("%d", &v);
            A[u-1][v-1] = 1;
        }
    }


    /*
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < n; j++) {
            printf("%d", A[i][j]);
            if(j != n-1) printf(" ");
        }
        printf("\n");
    }
    */

    dfs_1();

    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, 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;
}

//DFS with stack
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 { // v == -1
            S.pop();
            color[u] = BLACK;
            f[u] = ++tt;
        }
    }
}

void dfs(){
    //initialization
    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;
}

C++: #include <iostream>
using namespace std;
static const int MAX = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;
int M[MAX][MAX], n, tt = 0;
int d[MAX], f[MAX], color[MAX];

void dfs(int u)
{
    color[u] = GRAY;
    d[u] = ++tt;
    for (int i = 0; i != n; ++i)
    {
        if (M[u][i] && color[i] == WHITE)
        {
            dfs(i);
        }
    }
    color[u] = BLACK;
    f[u] = ++tt;
}

int main()
{
    int id, m, v;
    cin >> n;
    for (int i = 0; i != MAX; ++i)
    {
        d[i] = 0;
        f[i] = 0;
        color[i] = WHITE;
        for (int j = 0; j != MAX; ++j)
        {
            M[i][j] = 0;
        }
    }
    for (int i = 0; i != n; ++i)
    {
        cin >> id >> m;
        for (int j = 0; j != m; ++j)
        {
            cin >> v;
            M[id-1][v-1] = 1;
        }
    }
    for (int i = 0; i != n; ++i)
    {
        if (color[i] == WHITE) dfs(i);
    }

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

C++: #include <iostream>
using namespace std;
int G[101][101];
int d[101];
int f[101];
bool flag[101];
int n,v,k,p;
int t;

void check(int i){
	if(flag[i])return;
	flag[i]=true;
	t++;
	d[i]=t;
	for(int j=1;j<=n;j++){
		if(G[i][j]==1)check(j);
	}
	t++;
	f[i]=t;
	return;
}


int main(){
	cin >>n;
	for(int i=0;i<n;i++){
		cin >> v>>k;
		for(int j=0;j<k;j++){
			cin >> p;
			G[v][p]=1;
		}
	}
	t=0;
	for(int i=1;i<=n;i++)check(i);
	for(int i=1;i<=n;i++){
		cout << i<< " "<<d[i]<< " "<<f[i] <<endl;
	}
}

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

vector<int> G[102];
int d[102];
int f[102];
bool used[102];


int dfs(int i, int t){
    d[i] = t++;
    used[i] = true;
    for(vector<int>::iterator it = G[i].begin(); it != G[i].end(); ++it){
        if(!used[*it]){
            t = dfs(*it, t);
        }
    }
    
    f[i] = t++;
    return t;
}

int main()
{
    int n,u,k,v;
    cin >> n;
    for(int i = 0; i < n; ++i){
        cin >> u >> k;
        for(int j = 0; j < k; ++j){
            cin >> v;
            G[u].push_back(v);
        }
    }
    int t = 1;
    for(int i = 1; i <= n; ++i){
        if(!used[i]){
            t = dfs(i,t);
        }
    }
    
    for(int i = 1; i <= n; ++i){
        cout << i << ' ' << d[i] << ' ' << f[i] << endl;
    }
}