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+1)
	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 <bits/stdc++.h>
using ll = long long;
using namespace std;
#define rep(i,n) for(int i=0, i##_len=(int)(n); i<i##_len; i++)
#define reps(i,n) for(int i=1 , i##_len=(int)(n);i<=i##_len;i++)
#define rrep(i,n) for(int i=((int)(n)-1);i>=0;i--)
#define rreps(i,n) for(int i=((int)(n));i>0;i--)
#define all(x) (x).begin(), (x).end()
#define F first
#define S second
#define mp make_pair
#define pb push_back
#define solve(a) ((a)?"Yes":"No")
typedef vector<long long> V;
typedef vector<V> VV;
typedef pair<long long , long long> P;
typedef vector<P> VP;
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;}
const long long INFLL = 1LL<<62;
const int INF = 1<<30;
const double PI=acos(-1);
int func(int serching,vector<vector<int>>&path,vector<pair<int,int>>&data,int no,vector<bool>&has){
    has[serching]=true;
    chmin(data[serching].F,no);
  
  // clog<<serching<<" in : "<<no<<endl;
    no++;
    for(auto itr=path[serching].begin();itr!=path[serching].end();itr++){
        if(has[*itr]==false){
       no= func(*itr,path,data,no,has);
        }
    }
    chmax(data[serching].S, no);
  //  clog << serching <<  " out : " << no << endl;
    return no+1;
}
int main(){
    int n;
    cin >>n;
    vector<vector<int>>path(n);
    vector<bool>has(n,false);
    vector<pair<int,int>>data(n,mp(INF,0));
    queue<int>q;
    q.push(0);
    int at;
    int u,k;
    int bef;
    rep(i,n){
        cin>>u>>k;
        u--;
        rep(j,k){
            cin>>bef;
            bef--;
            path[u].push_back(bef);
         //   clog<<u<< " -> "<<bef<<endl;
        }
    }
    rep(i,u){
        sort(all(path[i]));
    }
    int no=1;
    rep(i,n){
        if(has[i]==false){
       no= func(i,path,data,no,has);
        }
    }
    rep(i,n){
        printf("%d %d %d\n",i+1,data[i].F,data[i].S);
    }
}

C++: /*
 * ALDS1_11_B.cpp
 *
 *  Created on: May 5, 2018
 *      Author: 13743
 */

#include<iostream>
#include<vector>

using namespace std;

int d[101];
int f[101];
int time;

void dfsRec(vector<int>* a, int n, int v) {
	if(d[v] > 0) return;
	time++;
	d[v] = time;
	for(int &x:a[v]) {
		dfsRec(a, n, x);
	}
	time++;
	f[v] = time;
}

int main() {
	int n;
	vector<int> adj[101];

	cin >> n;
	for(int i=0; i<n; i++) {
		int v;
		int k;
		cin >> v >> k;
		for(int j=0; j<k; j++) {
			int u;
			cin >> u;
			adj[v].push_back(u);
		}
	}

	dfsRec(adj, n, 1);

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

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

void dfs_init();
void dfs(int u);

int n,**List,*deg,*d,*f;
bool **M;
string *color;
int vertex;
int tm;

int main(){
	cin>>n;
	List = new int*[n]; M = new bool*[n]; deg = new int[n]; color = new string[n]; d = new int[n]; f = new int[n];
	for(int i=0;i<n;i++) List[i] = new int[n]; for(int i=0;i<n;i++) M[i] = new bool[n];
	for(int i=0;i<n;i++){
		List[i] = List[i]-1;
		M[i] = M[i]-1;
	}
	List = List-1; M = M-1; deg = deg-1; color = color-1; d = d-1; f = f-1;

	for(int i=1;i<=n;i++){
		for(int j=1;j<=n;j++)
			M[i][j] = false;
		deg[i] = 0; d[i] = 0; f[i] = 0;
	}
	
	int k;
	for(int i=1;i<=n;i++){
		cin>>vertex>>k;
		for(int j=1;j<=k;j++){
			cin>>List[vertex][j];
			M[vertex][List[vertex][j]] = true;
		}
	}

	dfs_init();

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

	for(int i=1;i<=n;i++){
		delete [] (List[i]+1); delete [] (M[i]+1);
	}
	delete [] (List+1); delete [] (M+1);
	delete [] (deg+1); delete [] (color+1); delete [] (d+1); delete [] (f+1);
	cin.get(); cin.get();
}

void dfs_init(){
	for(int i=1;i<=n;i++) color[i] = "WHITE";
	tm = 0;
	for(int i=1;i<=n;i++){
		if(color[i]=="WHITE"){
			dfs(i);
		}
	}
}

void dfs(int u){
	color[u] = "GRAY";
	d[u] = ++tm;
	for(int v=1;v<=n;v++){
		if(M[u][v]==false) continue;
		if(color[v]=="WHITE"){
			dfs(v);
		}
	}
	color[u] = "BLACK";
	f[u] = ++tm;
}

C++: //aizu
#include <iostream>
#include <vector>
#include <bitset>
#include <algorithm>
using namespace std;

vector <int> v[101];

pair <int, int> af[101];

bitset <101> viz;

int cnt;

void DFS(int nod)
{
    cnt++;
    af[nod].first = cnt;
    viz[nod] = 1;

    for (size_t i = 0; i < v[nod].size(); ++i)
    {
        if (viz[v[nod][i]] == 0)
            DFS(v[nod][i]);
    }
    cnt++;
    af[nod].second = cnt;
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);

    int n, u, k, ind;
    cin >> n;
    for (int i = 1; i <= n; ++i)
    {
        cin >> u >> k;
        for (int j = 1; j <= k; ++j)
        {
            cin >> ind;
            v[u].push_back(ind);
        }
        sort(v[u].begin(), v[u].end());
    }

    for (int i = 1; i <= n; ++i)
        if (viz[i] == 0)
            DFS(i);

    for (int i = 1; i <= n; ++i)
        cout << i << " " << af[i].first << " " << af[i].second << "\n";
    return 0;
}