Go: package main

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

/***************************************************************
stackによる深さ優先探索を実装する。
***************************************************************/

const (
	N     = 100
	WHITE = 0
	GRAY  = 1
	BLACK = 2
)

var (
	n            int
	Adj          [N][N]int
	statusColor  [N]int
	discoverTime [N]int
	finishTime   [N]int
	clock        int
	nt           [N]int
)

/***************************************************************
Stackの定義:
- field
	container: ノードの格納されたスライス
	sp: スタックポインタ
- method
	size(): スタックに積まれているノードの個数を返す
	top(): スタックの一番上に積まれているノードを返す
	isEmpty(): スタックが空かどうかを返す
	pop(): スタックの要素をポップし削除する
	push(): スタックに要素を積む
***************************************************************/

type Stack struct {
	container []int
	sp        int
}

func (s *Stack) size() int {
	return len(s.container)
}

func (s *Stack) top() int {
	return s.container[s.sp]
}

func (s *Stack) isEmpty() bool {
	return s.sp == 0
}

func (s *Stack) pop() int {
	_pop := func() {
		s.container = s.container[:len(s.container)-1]
	}
	defer _pop()
	if s.isEmpty() {
		panic("There is no elements in stack!")
	}
	s.sp--
	return s.container[s.sp]
}

func (s *Stack) push(n int) {
	s.sp++
	s.container[s.sp] = n
}

func next(u int) int {
	for v := nt[u]; v < n; v++ {
		nt[u] = v + 1
		if Adj[u][v] == 1 {
			return v
		}
	}
	return -1
}

func _DFS(target int) {
	for i := 0; i < n; i++ {
		nt[i] = 0
	}
	stack := new(Stack)
	stack.container = make([]int, N)
	stack.push(target)
	statusColor[target] = GRAY
	clock++
	discoverTime[target] = clock
	for !stack.isEmpty() {
		u := stack.top()
		v := next(u)
		if v != -1 {
			if statusColor[v] == WHITE {
				statusColor[v] = GRAY
				clock++
				discoverTime[v] = clock
				stack.push(v)
			}
		} else {
			stack.pop()
			statusColor[u] = BLACK
			clock++
			finishTime[u] = clock
		}
	}
}

func DFS() {
	for i := 0; i < n; i++ {
		statusColor[i] = WHITE
		nt[i] = 0
	}
	clock = 0
	for i := 0; i < n; i++ {
		if statusColor[i] == WHITE {
			_DFS(i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, discoverTime[i], finishTime[i])
	}
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ = strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			Adj[i][j] = 0
		}
	}
	for i := 0; i < n; i++ {
		scanner.Scan()
		u, _ := strconv.Atoi(scanner.Text())
		scanner.Scan()
		k, _ := strconv.Atoi(scanner.Text())
		u--
		for j := 0; j < k; j++ {
			scanner.Scan()
			v, _ := strconv.Atoi(scanner.Text())
			v--
			Adj[u][v] = 1
		}
	}

	DFS()
}

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

int n, t = 0, d[110] = {}, f[110];
bool a[110][110] = {};

void dfs(int u){
  d[u] = ++t;
  
  for(int i = 1;i <= n;i++) if(a[u][i] && d[i] == 0) dfs(i);
  
  f[u] = ++t;
}

int main(){
  
  int u, k, v;
  
  cin >> n;
  for(int i = 0;i < n;i++){
    cin >> u >> k;
    for(int j = 0;j < k;j++){
      cin >> v;
      a[u][v] = true;
    }
  }
  
  for(int i = 1;i <= n;i++){
    for(int j = 1;j <= n;j++){
      if(a[i][j] && d[i] == 0) dfs(i);
    }
  }
  
  for(int i = 1;i <= n;i++) cout << i << " " << d[i] << " " << f[i] << endl;
  
  return 0;
}

C++: #include<stdio.h>
#define N 100
#define WHITE 0  //未访问节点
#define GRAY 1
#define BLACK 2

int n,M[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(u=0;u<n;u++)
	{
		color[u]=WHITE;
	}
	tt=0;
	for(u=0;u<n;u++)
	{
		if(color[u]==WHITE)
			dfs_visit(u);
	}
	for(u=0;u<n;u++)
	{
		printf("%d %d %d\n",u+1,d[u],f[u]);
	}
}
int main()
{
	int u,v,k,i,j;
	scanf("%d",&n);
	for(i=0;i<n;i++)
	{
		for(j=0;j<n;j++)
			M[i][j]=0;
	}
	for(i=0;i<n;i++)
	{
		scanf("%d %d",&u,&k);
		u--;
		for(j=0;j<k;j++)
		{
			scanf("%d",&v);
			v--;
			M[u][v]=1;
		}
	}
	dfs();
	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 BRACK = 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;
}

//????????????????????£?????±???????????¢?´¢

void dfs_visit(int r) {
	for (int i = 0; i < n; i++) {//nt????????????
		nt[i] = 0;
	}

	stack<int> S;//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] = BRACK;
			f[u] = ++tt;
		}
	}
}

void dfs() {
	//?????????
	for (int i = 0; i < n; i++) {
		color[i] = WHITE;
		nt[i] = 0;
	}
	tt = 0;

	//????¨???????u????§??????¨????????±???????????¢?´¢
	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++) {//??????M????????????????´?
		cin >> u >> k;
		u--;//0?????????????????????
		for (int j = 0; j < k; j++) {
			cin >> v;
			v--;//0?????????????????????
			M[u][v] = 1;
		}
	}

	dfs();

	return 0;
}

C++: #include<iomanip>
#include<limits>
#include<thread>
#include<utility>
#include<iostream>
#include<string>
#include<algorithm>
#include<set>
#include<map>
#include<vector>
#include<stack>
#include<queue>
#include<cmath>
#include<numeric>
#include<cassert>
#include<random>
#include<chrono>
#include<unordered_map>
#include<fstream>
#include<list>
#include<typeinfo>
#include<functional>
using namespace std;
typedef unsigned long long int ull;
typedef long long int ll;
typedef pair<ll,ll> pll;
typedef pair<int,int> pi;
typedef pair<double,double> pd;
typedef pair<double,ll> pdl;
#define F first
#define S second
const ll E=1e18+7;
const ll MOD=1000000007;

vector<vector<ll>> edge;
vector<ll> dp;
vector<ll> fi;

ll Time=0;

void dfs(ll where){
    Time++;
    dp[where]=Time;
    for(int i=0;i<edge[where].size();i++){
        const ll &to=edge[where][i];
        if(dp[to]!=-1){continue;}
        dfs(to);
    }
    Time++;
    fi[where]=Time;
}

int main(){
    ll n;
    cin>>n;
    edge.resize(n);
    dp.resize(n,-1);
    fi.resize(n,-1);
    for(int i=0;i<n;i++){
        ll u,k;
        cin>>u>>k;
        u--;
        for(int t=0;t<k;t++){
            ll v;
            cin>>v;
            v--;
            edge[u].push_back(v);
        }
    }
    for(int i=0;i<n;i++){
        if(dp[i]==-1){dfs(i);}
    }
    for(int i=0;i<n;i++){
        cout<<i+1<<" "<<dp[i]<<" "<<fi[i]<<endl;
    }
    
    
    
    return 0;
}