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<stack>
using namespace 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[N];

int next() {
	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[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[u] = BLACK;
				f[u] = ++tt;
			}
		}
	}
}

void dfs() {
	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 u = 0; i < n; u++) {
		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 i = 0; i < N; i++) {
			cin >> v;
			v--;
			M[u][v] = 1;
		}
	}
	dfs();

	return 0;
}

C++: #include <cassert>
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <algorithm>
#include <bitset>
#include <complex>

#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#define rep(i,n) for(int i=0;i<(n); i++)
#define rep2(i,n) for(int i=1;i<=(n);i++)
#define WHITE 0
#define GRAY 1
#define BLACK 2

using namespace std;
typedef long long ll;
const int NMAX = 100;
const int k = 200000;
static const int INF = 1<<29;
string s,t,ans;
int dp[3001][3001];
ll gcd(ll a, ll b){
if(a<b) swap(a,b);
    if(b==0) return a;
    return gcd(b, a%b);
}
int n,M[NMAX+1][NMAX+1]={0};
int color[NMAX]={WHITE},d[NMAX],f[NMAX],tt;

void dfs_visit(int u){
    color[u]=GRAY;
    d[u] = ++tt; //最初の訪問
    rep2(v,n){
        if(M[u][v]==0) continue;
        if(color[v]==WHITE){
            dfs_visit(v); //再帰
        }
    }
    color[u]=BLACK;
    f[u] = ++tt; //訪問完了
}

void dfs(){
    //初期化はcolor[NMAX]の定義で完了
    tt=0; //時間メモ
    rep2(u,n){
        if(color[u]==WHITE){
            dfs_visit(u); //まだ未踏の地であったらdfs_visit関数を動かす。
        }
    }
    rep2(u,n){
        cout << u << " " << d[u] << " " << f[u] << endl;
    }
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0); //この2行はより速度を向上させる
    // 追加２, 以降 cin の入力元が 'input.txt' になる


    int u,v,k;
    cin >> n;
    rep2(i,n){
        int u,k;
        cin >> u >> k;
        int v[k+1];
        rep2(j,k) cin >> v[j];
        rep2(j,k){
            M[i][v[j]]=1;
        }
    }
    dfs();
    return 0;
}

C++: #include <cstdio>
#include <cstring>
#include <stack>
#define N 110
using namespace std;
stack<int> s;
int n;
int m[N][N];
int used[N];
int time = 1;
int bb_start[N];
int bb_end[N];
int getnext(int u){
    for(int i = 1; i <= n; i++){
        if(m[u][i] == 1 && used[i] == 0) return i;
    }
    return -1;
}
void dfs(int root){
    used[root] = 1;
    bb_start[root] = time++;

    while(!s.empty()) s.pop();
    s.push(root);
    while(!s.empty()){
        int u = s.top();
        int v = getnext(u);
        if(v != -1 && used[v] == 0){
            used[v] = 1;
            bb_start[v] = time++;
            s.push(v);
        } else{
            bb_end[u] = time++;
            s.pop();
        }
    }
}
int main(){
    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++) used[i] = 0;
    scanf("%d", &n);
    for(int p = 0; p < n; p++){
        int node, k;
        scanf("%d %d", &node, &k);
        for(int i = 0; i < k; i++){
            int b;
            scanf("%d", &b);
            m[node][b] = 1;
        }
    }
    for(int i = 1; i <= n; i++) if(used[i] == 0) dfs(i);
    for(int i = 1; i <= n; i++){
        printf("%d %d %d\n", i, bb_start[i], bb_end[i]);
    }
    return 0;
}

C++: def dfs(n):
    global t
    S[n] = t
    DP[n]=1
    for i in A[n][2:]:
        if not DP[i]:
            t += 1
            dfs(i)
    t += 1
    F[n] = t
n = int(input())
A = [0]*(n+1)
S = [0]*(n+1)
F = [0]*(n+1)
DP = [0]*(n+1)
for i in range(n):
    A[i+1] = [int(i) for i in input().split()]
t = 0
for i in range(1,n+1):
    if not DP[i]:
        t+=1
        dfs(i)
for i in range(1,n+1):
    tmp = "{} {} {}".format(i,S[i],F[i])
    print(tmp)