Go: package main

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

type vertexId int

type vertex struct {
	id vertexId
	firstVisitAt int
	finishVisitAt int
	adjs []vertexId
}

func createVertex(id int, adjsInt []int) vertex {
	adjs := make([]vertexId, len(adjsInt))
	for i := 0; i < len(adjs); i++ {
		adjs[i] = vertexId(adjsInt[i])
	}
	return vertex{
		id: vertexId(id),
		firstVisitAt: 0,
		finishVisitAt: 0,
		adjs: adjs,
	}
}

func (v *vertex) isVisited() bool {
	return v.firstVisitAt > 0
}

func dfs(currentId vertexId, timestamp int, vertices []vertex) int {
	currentVertex := &vertices[currentId-1]
	if currentVertex.isVisited() {
		return timestamp
	}
	timestamp = timestamp + 1
	currentVertex.firstVisitAt = timestamp
	for _, adjId := range currentVertex.adjs {
		timestamp = dfs(adjId, timestamp, vertices)
	}
	timestamp = timestamp + 1
	currentVertex.finishVisitAt = timestamp
	return timestamp
}

func solveDfs(vertices []vertex) {
	timestamp := 0
	for {
		vid := vertexId(-1)
		for i := 0; i < len(vertices); i++ {
			if !vertices[i].isVisited() {
				vid = vertexId(i+1)
				break
			}
		}
		if vid > 0 {
			timestamp = dfs(vid, timestamp, vertices)
		} else {
			break
		}
	}
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	vertices := make([]vertex, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjN, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjs := make([]int, adjN)
		for j := 0; j < adjN; j++ {
			adjId, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			adjs[j] = adjId
		}
		vertices[i] = createVertex(id, adjs)
	}

	solveDfs(vertices)

	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", vertices[i].id, vertices[i].firstVisitAt, vertices[i].finishVisitAt)
	}
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func nextInt(sc *bufio.Scanner) (int, error) {
	return strconv.Atoi(nextText(sc))
}

C++: // 深さ優先探索
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<stack>
#include<algorithm>
#include<iostream>
#include<cmath>
#include<vector>

using namespace std;

#define MAX_N 100
// 値の定義
const int EXIST = 1;
const int NO_EXIST = 0;

const int WHITE = 0;// 未訪問
const int GRAY = 1; // 訪問中
const int BLACK = 2;// 訪問完了

// グラフ情報を保持する配列
int ary_graph[MAX_N + 1][MAX_N + 1];

// 各頂点の訪問状態を保持する配列
int color[MAX_N + 1];

// 発見時刻と完了時刻を保持する構造体
typedef struct
{
    int start_time;
    int end_time;
}SearchTime;

SearchTime st_SearchTime[MAX_N];
int search_T = 1;

void depthFirstSearch(int now_vertex, int vertex_num);

int main(void)
{
    int n, u, num, v_num;

    for(int i = 0; i < MAX_N + 1; i++)
    {
        color[i] = WHITE;

        for(int j = 0; j < MAX_N + 1; j++)
        {
            // 配列の初期化
            ary_graph[i][j] = NO_EXIST;
        }
    }

    cin >> n;

    for(int i = 0; i < n; i++)
    {
        cin >> u;
        cin >> num;

        for(int j = 0; j < num; j++)
        {
            // 隣接点を記憶する
            cin >> v_num;
            ary_graph[u][v_num] = EXIST;
        }
    }

    // 深さ優先探索を実施
    for(int i = 1; i <= n; i++)
    {
        if( color[i] == WHITE )
        {
            st_SearchTime[i].start_time = search_T;
            depthFirstSearch(i, n);
        }
    }

    // 結果の表示
    for(int i = 1; i <= n; i++)
    {
        printf("%d %d %d\n", i, st_SearchTime[i].start_time, st_SearchTime[i].end_time);
    }

    return 0;
}

// 深さ優先探索を実施する関数
// now_vertex : 現在の頂点のNo.
// next_vertex : 次の頂点のNo.
// vertex_num : グラフの頂点数
void depthFirstSearch(int now_vertex, int vertex_num)
{

    for(int i = 1; i <= vertex_num; i++)
    {
        if( color[i] == WHITE
            && ary_graph[now_vertex][i] == EXIST )
        {
            // 訪問中
            color[i] = GRAY;

            // 発見時刻の設定
            search_T++;
            st_SearchTime[i].start_time = search_T;

            depthFirstSearch(i, vertex_num);
        }
    }

    // 訪問完了
    color[now_vertex] = BLACK;

    // 終了時刻の設定
    search_T++;
    st_SearchTime[now_vertex].end_time = search_T;

    return;
}

C++: #include "bits/stdc++.h"
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];
int color[N],d[N],f[N],tt;
int nt[N];

//u?????£??\??????v?????????????????????
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[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;
	//????¨???????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) {
		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<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, tt;
int M[N][N], color[N], d[N], f[N], nt[N]; 

int next(int u){
	for(int v = nt[u]; v < n; v++) {
		nt[u] = v + 1;
		if(M[u][v] = 1) 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 {
		   color[v] = BLACK;
		   S.pop();
		   f[v] = ++tt;
		}
	} 
}


void dfs() {
	for(int i = 0; i < n; i++) {
	     color[i] = WHITE;
	}	
	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 n, k , u, v;
	cin >> n;
	for(int i = 0; i < n; i++) {
		for(int j = 0; j < n; j++) {
			M[i][j] = 0;
		}
	}
	cin >> k >> u;
	u--;
	for(int i = 0; i < k; i++) {
	    cin >> v;
	    v--;
		M[u][v] = 1; 
	}
	dfs();
	return 0;
}

C++: #include <iostream>


using namespace std;


using ll = long long;


const ll MAX = 100;

bool adj[MAX + 1][MAX + 1] = {};
bool visited[MAX + 1] = {};
ll d[MAX + 1], f[MAX + 1];
ll n;
ll t = 1;


void dfs(ll now)
{
    visited[now] = true;
    d[now] = t++;
    for (ll i = 1; i <= n; i++) {
        if (!adj[now][i])
            continue;
        if (visited[i])
            continue;

        dfs(i);
    }
    f[now] = t++;
}


int main()
{
    cin >> n;
    for (ll i = 0; i < n; i++) {
        ll u, k;
        cin >> u >> k;
        for (ll j = 0; j < k; j++) {
            ll v;
            cin >> v;
            adj[u][v] = true;
        }
    }

    for (ll i = 1; i <= n; i++) {
        if (!visited[i])
            dfs(i);
    }

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