Go: package main

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

var sc = bufio.NewScanner(os.Stdin)
var depth [101]int
var finish [101]int
var d [101]int
var n, time int

func nextInt() int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return i
}
func visit(graph [][]int, u int) {
	depth[u] = 1
	time++
	d[u] = time
	for i := 0; i < n; i++ {
		if graph[u][i] == 1 {
			if depth[i] == 0 {
				visit(graph, i)
			}
		}
	}
	depth[u] = 2
	time++
	finish[u] = time
}
func main() {
	sc.Split(bufio.ScanWords)

	n = nextInt()
	graph := make([][]int, n)
	for i := 0; i < n; i++ {
		graph[i] = make([]int, n)
	}
	for i := 0; i < n; i++ {
		s := nextInt()
		t := nextInt()
		if t == 0 {
			continue
		}
		for i := 0; i < t; i++ {
			u := nextInt()
			graph[s-1][u-1] = 1
		}
	}
	for i := 0; i < n; i++ {
		if depth[i] == 0 {
			visit(graph, i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, d[i], finish[i])
	}
}

C++: #include<stdio.h>
struct
{
    int Top=0;
    int s[20000];
    bool Empty()
    {
        return Top==0;
    }
    void push(int x)
    {
        s[++Top]=x;
    }
    void pop()
    {
        Top--;
    }
    int top()
    {
        return s[Top];
    }
}S;
const int N=100;
const int bai=0;
const int hui=1;
const int hei=2;
int n,tu[N][N];
int fx[N],js[N],sum,nt[N],jilu[N];
int next(int u)
{
    for (int v=nt[u];v<n;v++)
    {
        nt[u]=v+1;
        if(tu[u][v]) return v;
    }
    return -1;
}
void DFS_visit(int r)
{

    S.push(r);
    jilu[r]=hui;
    fx[r]=++sum;
    while(!S.Empty())
    {
        int u=S.top();
        int v=next(u);
        if(v!=-1)
        {
            if(jilu[v]==bai)
            {
                jilu[v]=hui;
                fx[v]=++sum;
                S.push(v);
            }
        }
        else
        {
            S.pop();
            jilu[u]=hei;
            js[u]=++sum;    
        }
    }
}
void DFS()
{
    sum=0;
    for (int u=0;u<n;u++)
    {
        if(jilu[u]==bai)
            DFS_visit(u);
    }
    for (int i=0;i<n;i++)
    {
        printf("%d %d %d\n",i+1,fx[i],js[i]);
    }
}
int main()
{
    int u,k,v;
    scanf("%d",&n);
    for (int i=0;i<n;i++)
    {
        scanf("%d%d",&u,&k);
        u--;
        for(int j=0;j<k;j++)
        {
            scanf("%d",&v);
            v--;
            tu[u][v]=1;
        }
    }
    DFS();
    return 0;
}

C++: #include "bits/stdc++.h"
#define rep(i,n) for(int i = 0; i < (n); ++i)
using namespace std;
/*
using ll = long long;
using P = pair<int, int>;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
*/

int table[101][101], time_table[101][2];
int common_time = 1, n;

void dfs(int node){
    if(time_table[node][0] == 0) time_table[node][0] = common_time++;
    else return;
    for(int i = 1; i <= n; i++){
        if(table[node][i] == 1) dfs(i);
    }
    time_table[node][1] = common_time++;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> n;
    int id, k, v;
    rep(i,n+1){
        rep(j,n+1) table[i][j] = 0;
        time_table[i][0] = 0;
        time_table[i][1] = 0;
    }
    rep(i,n){
        cin >> id >> k;
        rep(j,k){
            cin >> v;
            table[id][v] = 1;
        }
    }
    for(int i = 1; i <= n; i++){
        dfs(i);
    }
    for(int i = 1; i <= n; i++){
        cout << i << " " << time_table[i][0] << " " << time_table[i][1] << endl;
    }
    return 0;
}

C++: #include <iostream>
using namespace std;
int n,g[100][100],c[100],f[100],e[100],t=1;
void dfs(int now){
  c[now]=1;
  f[now]=t;
  t++;
  for(int i=0;i<n;i++) if(g[now][i]&&c[i]!=1){
      dfs(i);
      t++;
    }
  e[now]=t;
}
int main(){
 
  int a,b,tmp;
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>a>>b;
    for(int j=0;j<b;j++){
      cin>>tmp;
      g[a-1][tmp-1]=1;
    }
  }
  for(int i=0;i<n;i++) if(c[i]!=1){
      dfs(i);
      t++;
    }
 
  for(int i=0;i<n;i++) cout<<i+1<<" "<<f[i]<<" "<<e[i]<<endl;
 
  return 0;
 
}

C++: #include <bits/stdc++.h>
#define FOR(i,a,b) for(int i= (a); i<(b); i++)
#define REP(i,n) for(int i=0;i < (n);i++)
#define ALL(obj) (obj).begin(),(obj).end()
using namespace std;

const long long INF = 1LL << 60;
const int MOD = (int)1e9 + 7;
typedef long long ll;
//約数列挙
vector<long long> divisor(long long n) {
    vector<long long> ret;
    for (long long i = 1; i * i <= n; i++) {
        if (n % i == 0) {
            ret.push_back(i);
            if (i * i != n) ret.push_back(n / i);
        }
    }
    //sort(ret.begin(), ret.end()); // 昇順に並べる
    return ret;
}
vector<bool> seen;
vector<int> start_time;vector<int> finish_time;
vector<vector<int> > g;
void dfs(int ind,int& cnt){
    start_time[ind]=++cnt;
    seen[ind]=true;
    for(int nextind : g[ind]){
        if(seen[nextind])continue;
        dfs(nextind,cnt);
    }
    finish_time[ind]=++cnt;
}
signed main () {
    int n;scanf("%d",&n);
    g.resize(n);
    REP(i,n){
        int ind,tmp;scanf("%d %d",&ind,&tmp);
        REP(j,tmp){
            int a;scanf("%d",&a);
            g[i].push_back(a-1);
        }
    }
    seen.assign(n,false);start_time.resize(n);finish_time.resize(n);
    int cnt =0;
    REP(i,n){
        if(seen[i])continue;
        dfs(i,cnt);
    }
    REP(i,n){
        printf("%d %d %d\n",i+1,start_time[i],finish_time[i]);
    }
    return 0;
}

C++: #include <iostream>
#include <set>
#include <vector>
#include <queue>
#include <stack>
#include <utility>

using namespace std;

typedef long long signed int ll;

constexpr ll NIL = -20000000000;

int g[101][101],n,d[101],f[101];

int main() {
    cin >> n;
    for(int i = 0;i < n;i++) {
        int u,k,v;
        cin >> u >> k;
        for(int j = 0;j < k;j++) {
            cin >> v;
            g[u][v]++;
        }
    }
    stack<int> dfs;
    int time = 2;
    dfs.push(1);
    d[1] = 1;
    while(!dfs.empty()){
        int u = dfs.top();
        bool fl = false;
        for(int i = 1;i <= n;i++){
            if(g[u][i] && d[i] == 0 && u != i) {
                dfs.push(i);
                cout << "push" << i  << "u:" << u<< endl;
                d[i] = time++;
                fl = true;
                break;
            }
        }
        if(!fl) {
            dfs.pop();
            f[u] = time++;
        }
    }
    for(int i = 1;i <=n;i++) {
        cout << i << " " << d[i] << " " << f[i] <<endl;
    }
}

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

typedef long long ll;
#define inf 1e9+7

int f[200],d[200];
bool table[200][200];
int cou;

void init(){
    for(int i=0;i<200;i++){
        f[i]=d[i]=-1;
    }
}

void dfs(int n,int itr){
    cou++;
    if(d[itr]<0)d[itr]=cou;
    for(int i=0;i<n;i++){
        if(d[i]<0&&table[itr][i]) dfs(n,i);
    }
    cou++;
    f[itr] = cou;
}

void solve(int n){
    for(int i=0;i<n;i++){
        if(d[i]<0)dfs(n,i);
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);


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

    solve(n);

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

    return 0;
}