Go: package main

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

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

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

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	G := make([][]int, N)
	for i := 0; i < N; i++ {
		u, k := sc.nextInt()-1, sc.nextInt()
		for j := 0; j < k; j++ {
			G[u] = append(G[u], sc.nextInt()-1)
		}
	}
	ans := make([][2]int, N)
	time := 0
	found := make(map[int]bool)
	var dfs func(cur int)
	dfs = func(cur int) {
		time++
		ans[cur][0] = time
		found[cur] = true
		for i := 0; i < len(G[cur]); i++ {
			next := G[cur][i]
			if !found[next] {
				dfs(G[cur][i])
			}
		}
		time++
		ans[cur][1] = time
	}
	for i := 0; i < N; i++ {
		if !found[i] {
			dfs(i)
		}
	}

	for i := 0; i < N; i++ {
		fmt.Fprint(wtr, i+1)
		for j := 0; j < 2; j++ {
			fmt.Fprint(wtr, " ")
			fmt.Fprint(wtr, ans[i][j])
		}
		fmt.Fprintln(wtr)
	}
	wtr.Flush()
}

C++: #include<iostream>
#include<cstdio>
#include<stack>
using namespace std;
static const int N = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;
static const int NIL = -1;

int n, M[N][N];
int color[N], d[N], f[N], tt;
int nt[N];

//u に隣接するvを番号順に取得
int next(int u){
    for(int v = nt[u]; v < n; v++){
        nt[u] = v + 1;
        if( M[u][v] ) return v; 
    }
    return NIL;
}

void dfs_visit(int r){
    stack<int> S;
    S.push(r);
    color[r] = GRAY;
    d[r] = ++tt;

    while(S.size() != 0){
        int u = S.top();
        int v = next(u);
        if(v != NIL){
            if(color[v] == WHITE){
                color[v] = GRAY;
                d[v] = ++tt;
                S.push(v);
            }
        }else{
            S.pop();
            color[u] = BLACK;
            f[u] = ++tt;
        }
    }
}

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

    //未訪問のuを始点として深さ優先探索
    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(){
    cin >> n;
    int u, k, v;

    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++){
        scanf("%d %d", &u, &k);
        for(int j = 0; j < k; j++){
            scanf("%d", &v);
            M[u-1][v-1] = 1;
        }
    }

    dfs_init();

    return 0;
}

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

using vvb = std::vector<std::vector<bool>>;

struct TimeStamp
{
    int discovered;
    int finished;
};

std::vector<TimeStamp> dfs(const vvb& edges)
{
    using namespace std;

    int time {1};
    const int n = edges.size();
    stack<int> st;
    vector<bool> reached(n);
    vector<TimeStamp> times(n);

    //すべての辺について行う
    for (int i = 0; i < n; ++i)
    {
        if (reached[i])
            continue;

        times[i].discovered = time++;
        st.push(i);
        
        //点iからつながるすべての辺を調べる
        while (!st.empty())
        {
            int top = st.top();
            for(int i = 0; i < n; ++i)
                if (!reached[i] && edges[top][i])
                {
                    reached[i] = true;
                    times[i].discovered = time++;
                    st.push(i);
                    break;
                }

            //その点からの探索候補がなければ前の点に戻る
            if (top == st.top())
            {
                times[top].finished = time++;
                st.pop();
            }
        }
    }

    return times;
}

void solve()
{
    using namespace std;

    int n;
    cin >> n;

    vvb edges(n, vector<bool>(n));

    //読み込み
    for (int i = 0; i < n; ++i)
    {
        int u, k;
        cin >> u >> k;

        for (int j = 0; j < k; ++j)
        {
            int v;
            cin >> v;
            edges[u - 1][v - 1] = true;
        }
    }

    auto times = dfs(edges);

    for (int i = 0; i < n; ++i)
    {
        cout << i + 1 << " " << times[i].discovered << " " << times[i].finished << endl;
    }
}

int main()
{
    solve();
    return 0;
}

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

// 深さ優先探索
vector<bool> seen;
int p=0;
int d[200],f[200];
void dfs(const Graph &G, int v) {
    if (!seen[v]) d[v]=p+1;
    seen[v] = true; // v を訪問済にする
    p++;f[v]=p;

    // v から行ける各頂点 next_v について
    for (auto next_v : G[v]) {
        if (seen[next_v]) {
            continue; // next_v が探索済だったらスルー
        }
        dfs(G, next_v); // 再帰的に探索
    }
    p++;f[v]=p;
}

int main() {
   int n;
   cin >> n;
   Graph G(n+1);
   for (int i=0; i<n; i++) {
       int u,k;
       cin >> u >> k;
       for (int j=0; j<k; j++) {
           int v;
           cin >> v;
           G[u].push_back(v);
       }
   }
   seen.assign(n+1,false);
   for (int i=1; i<n+1; i++) {
       if (!seen[i]) {
           dfs(G,i);
       }
   }
   for (int i=1; i<n+1; i++) {
       cout << i << " " << d[i] << " " << f[i] << endl;
   }
}