Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

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

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve

const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 最初にiを訪問した時刻。発見時刻
//f[i]: iの隣接リストを訪問し終えた時刻。完了時刻
var color, d, f [MAX]int

func dfs_visit(u int) {
	color[u] = GRAY
	time++
	d[u] = time
	//隣接を調べる
	for v := 0; v < n; v++ {
		if M[u][v] == 0 {
			continue
		}
		//隣接するvが、未訪問だった場合
		if color[v] == WHITE {
			dfs_visit(v)
		}
	}
	//訪問完了処理
	color[u] = BLACK
	time++
	f[u] = time
	//訪問完了
}

func dfs() {
	//初期化
	for u := 0; u < n; u++ {
		color[u] = WHITE
	}
	time = 0

	//未訪問のuを始点として、深さ優先探索
	for u := 0; u < n; u++ {

		if color[u] == WHITE {
			dfs_visit(u)
		}
	}

	for u := 0; u < n; u++ {
		fmt.Println(u+1, d[u], f[u])
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	dfs()

}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#define N 2000

using namespace std;
vector<vector<int> > pa;
vector<vector<int> > ch;
int first[N] = {0};
int second[N] = {0};
int timestamp = 0;
void dfs(int x) {
    if (ch[x].empty()) {
        return;
    } else {
        for (int i = 0; i < ch[x].size(); i++) {
            if (first[ch[x][i]] * second[ch[x][i]] == 0) {
                timestamp++;
                first[ch[x][i]] = timestamp;
                dfs(ch[x][i]);
                timestamp++;
                second[ch[x][i]] = timestamp;
            }
        }
        return;
    }
}
int main() {
    int n;
    cin >> n;
    int temp = n;
    pa.clear(); pa.resize(N + 5);
    ch.clear(); ch.resize(N + 5);
    while (temp--) {
        int u, k, v;
        cin >> u >> k;
        for (int i = 0; i < k; i++) {
            cin >> v;
            pa[v].push_back(u);
            ch[u].push_back(v);
        }
    }
    int an = 0;
    for (int i = 1; i <= n; i++) {
        if (pa[i].empty()) {
            an = i;
        } else {
            sort(pa[i].begin(), pa[i].end(), less<int>());
        }
        if (ch[i].empty()) {
            ;
        } else {
            sort(ch[i].begin(), ch[i].end());
        }
    }
    timestamp++;
    first[an] = timestamp;
    dfs(an);
    timestamp++;
    second[an] = timestamp;
    for (int i = 1; i <= n; i++) {
        cout << i << ' ' << first[i] << ' ' << second[i] << '\n';
    }
}

C++: #include <stdio.h>
int d[101],e[101],t=0,n;
bool went[101],graph[101][101];
void dfs(int x){
    if(went[x])return;
    went[x]=true;
    t++;
    d[x]=t;
    for(int i=1;i<=n;i++){if(graph[x][i])dfs(i);}
    t++;
    e[x]=t;
    return;
}
int main(){
    int m,temp,a;
    scanf("%d",&n);
    for(int i=0;i<101;i++){
        for(int j=0;j<101;j++)graph[i][j]=false;
        went[i]=false;
    }
    for(int i=0;i<n;i++){
        scanf("%d%d",&a,&m);
        for(int j=0;j<m;j++){
            scanf("%d",&temp);
            graph[a][temp]=true;
        }
    }
    for(int i=1;i<=n;i++)dfs(i);
    for(int i=1;i<=n;i++)printf("%d %d %d\n",i,d[i],e[i]);
}

C++: #define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <limits.h>
using namespace std;
bool flag[101];
int d[101];
int f[101];
vector<int> v[101];
int t=1;
void dfs(int node){
	flag[node] = true;
	d[node] = t;
	for (int i = 0; i < v[node].size(); ++i){
		int tmp = v[node][i];
		if (!flag[tmp]){
			++t;
			dfs(tmp);
			++t;
		}
	}
	f[node] = t;
}
int main(){
	int n; scanf("%d",&n);
	for (int i = 0; i < n; ++i){
		int u, k; scanf("%d %d",&u,&k);
		int tmp;
		for (int j = 0; j < k; ++j){
			scanf("%d", &tmp);
			v[u].push_back(tmp);
		}
	}
	dfs(1);
	for (int i = 1; i <= n; ++i){
		cout << i << ' ' << d[i] << ' ' << f[i]+1 << '\n';
	}
}

C++: #include <set>
#include <map>
#include <list>
#include <queue>
#include <stack>
#include <cmath>
#include <ctype.h>
#include <ctime>
#include <cstdio>
#include <vector>
#include <string>
#include <bitset>
#include <cctype>
#include <cstdlib>
#include <cstring>
#include <utility>
#include <numeric>
#include <complex>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <cassert>
#include <iostream>
#include <iterator>
#include <algorithm>

using namespace std;
#define MAX 100
#define WHITE 1
#define GRAY 2
#define BLACK 3

int n;
int graph[MAX][MAX];
stack<int> st;
int *d,*f,*v;
int *color;

int next(int k){
	for(int i = v[k];i < n;i++){
		v[k]++;
		if(color[i] == WHITE && graph[k][i] == 1) return i;
	}
	return -1;
}

void dfs(int k){
	for(int i = 0;i < n;i++) v[i] = 0;
	int time = 0;

	st.push(k);
	d[k] = ++time;
	color[k] = GRAY;

	while(!st.empty()){
		int m = next(st.top());
		if(m != -1){
		  if(color[m] == WHITE){
				st.push(m);
				color[m] = GRAY;
				d[m] = ++time;
			}
		}else{
			f[st.top()] = ++time;
			color[st.top()] = BLACK;
			st.pop();
		}
	}
	for(int i = 0;i < n;i++){
		cout << i+1 << " " << d[i] << " " << f[i] << endl;
	}
}


int main(){
	cin >> n;
	//?????????
	color = new int[n];
	d = new int[n];
	f = new int[n];
	v = new int[n];
	for(int i = 0;i < n;i++){
		color[i] = WHITE;
		d[i] = 0;
		f[i] = 0;
		for(int j = 0;j < n;j++){
			graph[i][j] = 0;
		}
	}
	//data input
	for(int i = 0;i < n;i++){

		int t,k,p;

		cin >> t >>  k;
		for(int j = 0;j < k;j++){
			cin >> p;
			p--;
			graph[i][p] = 1;
		}
	}
	//graph
	for(int i = 0;i < n;i++){
		for(int j = 0;j < n;j++){
			cout << graph[i][j] << " ";
		}
		cout << endl;
	}
	dfs(0);
	return 0;
}

C++: #include<iostream>
#include<cstdio>
using namespace std;
typedef struct{
  int A[1000];
  int begin;
  int end;
  bool c;
}node;
node T[105];
int times=0;
int n;
void function(int num){
  if(T[num].begin==0){
  times++;
    T[num].begin=times;
	T[num].c=true;
  }
  for(int j=1;j<=n;j++){
    if(T[num].A[j]==1){
      if(T[j].c==false){
	T[num].A[j]=0;

	function(j);
      }
    }
  }
  if(T[num].end==0){
      times++;
      T[num].end=times;
    }
}
int main(){
  int num;
  int son;
  int z;
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>num;
    cin>>son;
    for(int j=0;j<son;j++){
      cin>>z;
      T[num].A[z]=1;
      }
  }
  for(int i=1;i<=n;i++){
    function(i);
  
  }
  for(int i=1;i<=n;i++){
      cout<<i<<" "<<T[i].begin<<" "<<T[i].end<<endl;
  }


  return 0;
}