Go: package main

/*
深さ優先探索
*/

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

func main() {
	scanner := makeScanner(8192)
	n := eGetInt(scanner)
	g := make([][]int, n+1)
	for i := 1; i < n+1; i++ {
		ints := eGetInts(scanner)
		num, vcount := ints[0], ints[1]
		g[i] = make([]int, vcount)
		for j := 0; j < vcount; j++ {
			g[num][j] = ints[j+2]
		}
	}
	hist := make([]struct{ d, f int }, n+1)
	t := 0
	var visit func(int)
	visit = func(num int) {
		if hist[num].d == 0 {
			stack := []int{}
			t++
			hist[num].d = t
			stack = append(stack, num)
			for len(stack) > 0 {
				// トップを訪問する
				top := stack[len(stack)-1]
				for i := 0; i < len(g[top]); i++ {
					if hist[g[top][i]].d == 0 {
						t++
						hist[g[top][i]].d = t
						stack = append(stack, g[top][i])
						goto endloop
					}
				}
				// 訪問場所がなくなったら
				// pop
				stack = stack[0 : len(stack)-1]
				t++
				hist[top].f = t
			endloop:
			}
		}
	}
	for i := 1; i < n+1; i++ {
		visit(i)
	}
	for i := 1; i < n+1; i++ {
		fmt.Println(i, hist[i].d, hist[i].f)
	}
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetInt64(r *bufio.Scanner) int64 {
	line := eGetLine(r)
	return eAtoInt64(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetInt64s(r *bufio.Scanner) []int64 {
	fields := eGetFields(r)
	ints := make([]int64, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoInt64(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}
func eAtoInt64(s string) int64 {
	n, err := strconv.ParseInt(s, 10, 64)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;
const int INF = 1001001001;
const int MOD = 1000000007;

template <typename T>
void print(const T &v);

vector<int> grid[105];
vector<bool> seen(105, false);
P ans[105];
int t = 0;

void dps(int now)
{
    seen[now] = true;
    ++t;
    ans[now].first = t;
    for (int next : grid[now])
    {
        if (seen[next])
        {
            continue;
        }
        dps(next);
    }
    ++t;
    ans[now].second = t;
}

int main()
{
    int n;
    cin >> n;
    for (int i = 0; i < n; i++)
    {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++)
        {
            int v;
            cin >> v;
            grid[u].push_back(v);
        }
    }
    for (int i = 1; i < n; i++)
    {
        if (!seen[i])
        {
            dps(i);
        }
    }
    for (int i = 1; i <= n; i++)
    {
        cout << i << ' ' << ans[i].first << ' ' << ans[i].second << endl;
    }
    return 0;
}

// Use For Debug
template <typename T>
void print(T const &v)
{
    for (int i = 0; i < v.size(); i++)
    {
        if (i)
            cout << ' ';
        cout << v[i];
    }
    cout << endl;
}

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 BLACK = 2;

int n,M[N][N];//グラフ情報
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 -1;
}

//深さ優先探索
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(){
    //初期化
    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 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++){
        cin >> u >> k;
        u--;
        for(int j = 0;j<k;j++){
            cin >> v;
            v--;
            M[u][v] = 1;
        }
    }
    dfs();
    return 0;
}

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

using namespace std;

int main(){
    stack<int> st;
    int n;
    cin >> n;
    int d[n] = {};
    int f[n] = {};
    int vnum[n][2] = {};
    bool vflag[n] = {};
    int tmp2;
    int num;
    vector<vector<int>> vertex;
    vector<vector<bool>> explored;
    vector<int> tmp;
    vector<bool> flag;
    for(int i=0;i<n;i++){
        cin >> num;
        cin >> num;
        vnum[i][0] = num;
        for(int j=0;j<num;j++){
            cin >> tmp2;
            tmp.push_back(tmp2);
            flag.push_back(false);
        }
        if(n==0){
            flag.push_back(false);
        }
        vertex.push_back(tmp);
        explored.push_back(flag);
        tmp.clear();
        flag.clear();
    }
    int cnt = 1;
    int s;
    st.push(0);
    while(!st.empty()){
        s = st.top();

        if((vnum[s][0]==0) && d[s]==0){
            vflag[s] = true;
            d[s] = cnt++;
            f[s] = cnt++;
            st.pop();
        }else if(vnum[s][0]==vnum[s][1]){
            vflag[s] = true;
            f[s] = cnt++;
            st.pop();
        }else if(vflag[vertex[s][vnum[s][1]]-1] && f[vertex[s][vnum[s][1]]-1]!=0 && d[s]==0){
            vflag[s] = true;
            d[s] = cnt++;
            f[s] = cnt++;
            st.pop();
        }else if(vflag[vertex[s][vnum[s][1]]-1]){
            vflag[s] = true;
            f[s] = cnt++;
            st.pop();
        }else if(vflag[s]){
            st.push(vertex[s][vnum[s][1]] - 1);
            vnum[s][1]++;
        }else{
            vflag[s] = true;
            d[s] = cnt++;
            st.push(vertex[s][vnum[s][1]] - 1);
            vnum[s][1]++;
        }
    }

    for(int i=0;i<n;i++){
        cout << i+1 << " " << d[i] << " " << f[i] << " " << endl;
    }
}