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>

using namespace std;
int n,u,k,v,**M,flag[100],s_time[100],f_time[100];
void creat()
{
    cin>>n;
  M=new int*[n];
  for(int i=0;i<n;i++)
    {
      M[i]=new int[n];
      flag[i]=0;
      for(int j=0;j<n;j++)
	M[i][j]=0;
    }
  int count=0;
  while(count<n)
    {
      count++;
      cin>>u>>k;
      for(int i=0;i<k;i++)
	{
	  cin>>v;
	  M[u-1][v-1]=1;
	}
    }
    /*for(int i=0;i<n;i++){
    for(int j=0;j<n;j++)
      cout<<M[i][j]<<' ';
    cout<<endl;
  }*/
}
int Time=0;
void dfs(int cur) {
    Time += 1;
    s_time[cur]=Time;
    //cout << "visiting " << cur+1 << ' ' << time << endl;
    flag[cur]=1;
    for (int dst=0;dst<n;dst++) {
            if (M[cur][dst]&&!flag[dst]) {
                dfs(dst);
            }
    }
    Time += 1;
    f_time[cur]=Time;
}
int main()
{
    creat();
    for(int i=0;i<n;i++)
    {
        if(!flag[i])
            dfs(i);
    }
    for(int i=0;i<n;i++)
    {
        cout<<i+1<<' '<<s_time[i]<<' '<<f_time[i]<<endl;
    }
    delete M;
    return 0;
}

C++: #include<iostream>

int main(){

  int n,a;
  std::cin>>n;

  int Adj[100][100],adj[100][100]={0},find[100][2],back[100],depth[100]={0},endflag[100]={0},flag;
  int u[n],k[n],kcou=0,timenow=0,v,pred,prev;
  for(int i=0;i<n;i++){
    std::cin>>u[i];
    std::cin>>k[i];
    for(int j=0;j<k[i];j++){
      std::cin>>Adj[i][j];
    }
  }
	
	/*
  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
    	std::cout<<Adj[i][j]<<" ";
    }
  	std::cout<<"\n";
  }*/
	
	v=0;

	while(timenow<n*2){
		flag=0;
		//std::cout<<find[v][0]<<" "<<find[v][1];
		if(find[v][0]==NULL){
			timenow++;
			find[v][0]=timenow;
			flag=1;
			//std::cout<<flag<<" 1";
		}else if(find[v][1]==NULL){
			if(endflag[v]==1){
				timenow++;
				find[v][1]=timenow;
				flag=2;
			}
			//std::cout<<flag<<" 2";
		}else{
			v=back[v];
			flag=3;
			//std::cout<<flag<<" 0";
		}

		if(flag==0){
			pred=depth[v];
			depth[v]++;
			prev=v;
			v=Adj[v][pred]-1;
			back[v]=prev;
			//std::cout<<flag<<"\n";
		}else if(flag==1){
			if(endflag[v]==1){
				depth[v]++;
			}else{
				pred=depth[v];
				depth[v]++;
				prev=v;
				v=Adj[v][pred]-1;
				back[v]=prev;
				//std::cout<<v<<"\n";
			}
		}else if(flag==2){
			v=back[v];
			//std::cout<<flag<<"\n";
		}
		if(depth[v]>k[v]-1){
			endflag[v]=1;
		}
		
	}
	
	
	
	
  for(int i=0;i<n;i++){
     std::cout<<i+1<<" "<<find[i][0]<<" ";
     std::cout<<find[i][1]<<"\n";
    //std::cout<<"\n";
  }

  return 0;
}

C++: #include<iostream>
using namespace std;
#define max 100

int aa[max][max];
int n;
int d[max];
int f[max];
int color[max];
int tt = 0;
int p[max];

void dfscount(int u) {
	color[u - 1] = 1;
	int x = -1;
	for (int i = n-1; i >= 0; i--) {
		if (aa[u - 1][i] == 1 && color[i] == 0) x = i + 1;
	}
	if (x == -1) {
		f[u - 1] = ++tt;
		color[u - 1] = 2;
		if (p[u - 1] == -1) {
			for (int i = 0; i < n; i++) {
				if (color[i] != 2) {
					d[i] = ++tt;
					dfscount(i + 1);
				}
			}
			return;
		}
		dfscount(p[u - 1]);
	}
	else {
		d[x - 1] = ++tt;
		p[x - 1] = u;
		dfscount(x);
	}
}

void dfs() {
	d[0] = ++tt;

	for (int i = 0; i < n; i++) {
		color[i] = 0;
		p[i] = -1;
	}

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

int main()
{
	cin >> n;

	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			aa[i][j] = 0;
		}
	}
	for (int i = 0; i < n; i++) {
		int num;
		cin >> num;
		int num1;
		cin >> num1;
		for (int j = 0; j < num1; j++) {
			int x;
			cin >> x;
			aa[num - 1][x - 1] = 1;
		}
	}

	dfs();

	return 0;
}

C++: #include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<climits>
#include<iostream>
#include<sstream>
#include<utility>
#include<map>
#include<vector>
#include<queue>
#include<algorithm>
#include<set>
#include<stack>
using namespace std;
typedef long long ll;
typedef pair<int,int>P;
int N,u,k,x,r=0;
vector<int>V[105];
bool f[105]={0};
P c[105];

void dfs(int p)
{
	if(f[p])return;
	r++;
	f[p]=1;
	c[p].first=r;
	for(int i=0;i<V[p].size();i++)
	{
		dfs(V[p][i]);
	}
	r++;
	c[p].second=r;
}

int main()
{
	scanf("%d",&N);
	for(int i=0;i<N;i++)
	{
		scanf("%d%d",&u,&k);u--;
		for(int j=0;j<k;j++)
		{
			scanf("%d",&x);x--;
			V[u].push_back(x);
		}
		sort(V[u].begin(),V[u].end());
	}
	for(int i=0;i<N;i++)
		dfs(i);
	for(int i=0;i<N;i++)
		printf("%d %d %d\n",i+1,c[i].first,c[i].second);
	return 0;
}

C++: #include<iostream>
#include<stdio.h>
using namespace std;
#define N 100
int n, M[N][N];
int search[N], d[N], f[N], t;

void dfs_visit(int u) {
    int v;
    search[u] = 1;
    d[u] = ++t;
    for (v=0; v<n; v++) {
        if (M[u][v] == 0) continue;
        if (search[v] == 0) {
            dfs_visit(v);
        }
    }
    search[u] = 2;
    f[u] = ++t;
}

void dfs() {
    int u;
    for (u=0; u<n; u++) {
        search[u] = 0;
    }
    t=0;
    for (u=0; u<n; u++) {
        if(search[u] == 0) dfs_visit(u);
    }
    for (u=0; u<n; u++) {
        cout << u+1 << " " << d[u] << " " << f[u] << endl;
    }
}

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

C++: #include <stdio.h>
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

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

void dfs_visit(int u){
  int v;
  color[u] = GRAY;
  d[u] = ++tt;
  for(v = 0 ; v < n; v++){
    if(M[u][v] == 0 ) continue;
    if(color[v] == WHITE){
      dfs_visit(v);
    }
  }
  color[u] = BLACK;
  f[u] = ++ tt;
}

void dfs(){
  int u;
  for(u = 0 ; u < n ; u++){
    color[u] = WHITE;
  }
  tt = 0;
  for(u = 0 ; u < n ; u++){
    if(color[u] == WHITE) dfs_visit(u);
  }
  for( u = 0 ; u < n ; u++){
    printf("%d %d %d\n" , u+1 , d[u] , f[u]);
  }
}

int main(){
  int u , v , k , i , j;

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

  dfs();

  return 0;
}