Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

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

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve

const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 最初にiを訪問した時刻。発見時刻
//f[i]: iの隣接リストを訪問し終えた時刻。完了時刻
var color, d, f [MAX]int

func dfs_visit(u int) {
	color[u] = GRAY
	time++
	d[u] = time
	//隣接を調べる
	for v := 0; v < n; v++ {
		if M[u][v] == 0 {
			continue
		}
		//隣接するvが、未訪問だった場合
		if color[v] == WHITE {
			dfs_visit(v)
		}
	}
	//訪問完了処理
	color[u] = BLACK
	time++
	f[u] = time
	//訪問完了
}

func dfs() {
	//初期化
	for u := 0; u < n; u++ {
		color[u] = WHITE
	}
	time = 0

	//未訪問のuを始点として、深さ優先探索
	for u := 0; u < n; u++ {

		if color[u] == WHITE {
			dfs_visit(u)
		}
	}

	for u := 0; u < n; u++ {
		fmt.Println(u+1, d[u], f[u])
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	dfs()

}

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 + 1;
		if (M[u][v]) return v;
	}
	return -1;
}

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

	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] = 1;
	}
	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 <iostream>
#include<string>
#include<cmath>
#include<algorithm>
#include<cctype>
#include<queue>
#include<stack>
#include<stdio.h>
#include<vector>
#include<set>
#include<map>
#include<array>
#include<iomanip>
#define rep(i,n) for(int i=0;i<n;i++)
typedef int long long ll;

using namespace std;
static const int WHITE =0;
static const int GRAY=1;
static const int BLACK=2;
static const int N=100;

int n,color[N],tt,d[N],f[N];
int M[N][N];
int nt[N];
int next(int u){
    for(int v=nt[u];v<n;v++){
        nt[u]=v+1;//頂点に複数頂点隣接してる場合、小さいのから取り出せるように、
        //nt[u]nextで渡した頂点の数がはいる
        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[v]=BLACK;
            f[u]=++tt;
        }
    }
    
}

void dfs(){
    
    rep(i,n){color[i]=WHITE;nt[i]=0;}tt=0;
    
    
    rep(i,n){
        if(color[i]==WHITE){
            dfs_visit(i);
           }
    }
        
        
    rep(i,n){
        
        cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
    }
    
    
    
    
    
}



int main(){
    
    cin>>n;
    rep(i,n){
        int k,l;cin>>k>>l;
        k--;
        for(int j=0;j<l;j++){
            int u;
            cin>>u;
            M[k][u-1]=1;
        }
    }
  /*  rep(i,n){
        rep(j,n){cout<<M[i][j];}
    cout<<endl;
    }*/
    dfs();
    
    
return 0;
}

C++: #include <iostream>
#include <utility>
#include <string>
#include <algorithm>
#include <set>
#include <queue>
#include <vector>
#define MAX 10010
#define rep(i,p) for(int i=0;i<p;i++)
#define pb push_back
using namespace std;
int n,hoge,foo,visit_time=1;
int graph[MAX][MAX] = {0};
int d[MAX]; // ????????????
int f[MAX]; // ??£??\????????????????????????

void dfs (int cur) {
  // visiting cur
  d[cur] = visit_time;
  visit_time++;

  rep(dst,n) {
    if (graph[cur][dst] == 1 && d[dst] == -1) dfs(dst);
  }
  f[cur] = visit_time;
  visit_time++;
}

int main(){
  cin >> n;
  rep(i,n) {
    d[i] = -1;
    f[i] = -1;
  }
  rep(i,n) {
    cin >> hoge >> foo;
    rep(j,foo) {
      cin >> hoge;
      graph[i][hoge-1] = 1;
    }
  }
  dfs(0);
  rep(i,n) cout << i+1 << " " << d[i] << " " << f[i] << endl;
  return 0;
}

C++: #include<bits/stdc++.h>
#define r(i,a,n) for(int i=a;i<n;i++)
using namespace std;
int n,u,k,v,a[101][101],start[101],end[101],p,f[101];
void dfs(int u){
	if(!f[u]){
    f[u]++;
    start[u]=++p;
    r(i,1,n+1)if(a[u][i])dfs(i);
    end[u]=++p;
  }
}
int main(){
	cin>>n;
	r(i,0,n){
    cin>>u>>k;
		r(i,0,k){
      cin>>v;
			a[u][v]++;
		}
	}
	r(i,1,n+1)if(!f[i])dfs(i);
	r(i,1,n+1)cout<<i<<' '<<start[i]<<' '<<end[i]<<endl;
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#define rep(i,n) for(int i=0;i<n;++i)
#define rep1(i,n) for(int i=1;i<=n;++i)
using namespace std;
class Graph{
private:
  int node;
  int edge_num;
  vector<vector<int>> edge;  
  vector<int> f;
  vector<int> d;
  int time;
public:
  //***************Constractor****************************
  Graph(int n,vector<int> a,vector<int> b){
    node = n;
    edge_num = a.size();
    time = 1;
    edge.resize(node);
    f.resize(node,0);
    d.resize(node);    
    rep(i,edge_num){
      edge[a[i]].push_back(b[i]);
    }
  }

  //***********************************************
  
  void simple_dfs(int v){
    f[v] = time++;
    for(auto w:edge[v]){
      if(f[w]>0) continue;
      simple_dfs(w);
    }
    d[v] = time++;
  }

  void run_dfs(int s){//check each node can reach goal
    rep(i,node){
      if(f[i]<=0) simple_dfs(i);
    }
  }

  void show(){
    rep(i,node){
      cout << i+1 << " " << f[i] << " " << d[i] << "\n";
    }
  }
};


int main()
{
  int n;
  cin >> n;
  vector<int> a,b;
  rep(i,n){
    int aa;cin >> aa;aa--;
    int m;cin >> m;
    rep(i,m){
      int bb;cin >> bb;bb--;
      a.push_back(aa);
      b.push_back(bb);      
    }
  }

  Graph gp(n,a,b);
  gp.run_dfs(0);
  gp.show();
  
  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> pll;

vector<set<ll>> v(101);
vector<ll> st(101,-1);
vector<ll> et(101,-1);

ll dfs(ll n,ll time) {
  st[n]=time;
  time++;
  for(auto p:v[n]) {
    if(st[p]<0) {
      time=dfs(p,time);
    }
  }
  et[n]=time;
  return time+1;
}

int main() {
  ll n;
  cin >> n;
  for(ll i=0;i<n;i++) {
    ll f,tn;
    cin >> f >> tn;
    for(ll j=0;j<tn;j++) {
      ll temp;
      cin >> temp;
      v[f].insert(temp);
    }
  }
  for(ll i=1;i<=n;i++) {
    v[0].insert(i);
  }
  dfs(0,0);
  for(ll i=1;i<=n;i++) {
    cout << i << " " << st[i] << " " << et[i] << endl;
  }
}