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<stack>

using namespace std;

int  n, M[100][100], d[100], f[100], color[100], time, nt[100], W = 0, G = 1, B = 2;

int next (int u) {

    int v;
    for (v = nt[u]; v < n; v++) {
        nt[u] = v + 1;
        if (M[u][v] != 0) {
            return v;
        }
    }
    return -1;

}

void dfs_visit (int r) {

    int i, u, v;

    for (i = 0; i < n; i++) {
        nt[i] = 0;
    }

    stack<int> S;
    S.push(r);
    color[r] = G;
    d[r] = ++time;

    while (!S.empty()) {
        u = S.top();
        v = next (u);
        if (v != -1) {
            if (color[v] == W) {
                color[v] = G;
                d[v] = ++time;
                S.push(v);
            }
        } else {
            S.pop();
            color[u] = B;
            f[u] = ++time;
        }
    }

}

void dfs () {

    int i, u;

    for (i = 0; i < n; i++) {
        color[i] = W;
        nt[i] = 0;
    }
    time = 0;

    for (u = 0; u < n; u++) {
        if (color[u] == W) {
            dfs_visit(u);
        }
    }

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

}

int main () {

    int u, k, v, 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 <iostream>
#include <vector>

using namespace std;

void DFS(vector<vector<int>>& graph, int v, int& time, vector<int>& d, vector<int>& f){
    time++;
    d[v] = time;
    for( int i = 0 ; i < graph[v].size(); i++){
        if(d[graph[v][i]] == -1){
            DFS(graph, graph[v][i], time, d, f);
        }
    }

    time++;
    f[v] = time;

    return;
}

int main(){

    int n;
    cin >> n;

    vector<vector<int>> graph(n);

    for(int i = 0; i < n; i++ ){
        int v, k;
        cin >> v >> k;
        for(int j = 0; j < k ; j++){
            int v2;
            cin >> v2;
            graph[v-1].push_back(v2-1);
        }
    }

    vector<int> d(n, -1);
    vector<int> f(n, -1);
    int time = 0;

    for(int i = 0 ; i < n ; i++){
        if( d[i] == -1 ){
            DFS(graph, i, time, d, f);
        }
    }

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

    return 0;
}

C++: #include<iostream>
#include<vector>
#include<algorithm>
#include<cmath>
#include<ctime>

using namespace std;
using ll = long long;
using vint = vector<int>;

void dfs(int k, int &t, vector<vector<int> >&g, vector<int>&d, vector<int>&f){
  d[k] = t;
  for(int i = 0; i < g[k].size(); i++){
    if(d[g[k][i]] == -1) dfs(g[k][i], ++t, g, d, f);
  }
  f[k] = ++t;
}

int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  int ti = clock();
  // start-----------------------------------------------
  int n; cin >> n;
  vector<vector<int> > g(n);
  vector<int> d(n, -1);
  vector<int> f(n, -1);
  for(int i = 0; i < n; i++){
    int t, k; cin >> t >> k;
    for(int j = 0; j < k; j++){
      int v; cin >> v;
      v--;
      g[i].push_back(v);
    }
  }
  int a = 0;
  for(int i = 0; i < n; i++){
    if(d[i] == -1) dfs(i, ++a, g, d, f);
  }
  for(int i = 0; i < n; i++){
    cout << i+1 << ' ' << d[i] << ' ' << f[i] << endl;
  }
  // end-----------------------------------------------
  // cerr << 1.0 * (clock() - ti) / CLOCKS_PER_SEC << endl;
}

C++: #include <iostream>
#include <vector>
using namespace std;
vector<vector<int>> adjlist;
int time=1;
vector<int> d;
vector<int> f;
void input(int n){
	vector<int> f={0,0};
	adjlist.push_back(f);
  for(int i=0;i<n;i++){
    vector<int> list;
    int ln;
    cin>>ln;
    list.push_back(ln);
    cin>>ln;
    list.push_back(ln);
    for(int j=0;j<ln;j++){
      int an;
      cin>>an;
      list.push_back(an);
    }
    adjlist.push_back(list);
  }
}

void depth_search(int id){
	vector<int> list=adjlist[id];
	for(int j=0;j<list[1];j++){
		if(d[list[2+j]]<0){
			d[list[2+j]]=++time;
			depth_search(list[2+j]);
		}
	}
	f[id]=++time;
}
 
void print(int n){
  for(int i=1;i<n+1;i++){
    cout<<i<<' '<<d[i]<<' '<<f[i]<<endl;
  }
}
int main(){
  int n;
  cin>>n;
	d=vector<int> (n+1,-1);
	f=vector<int> (n+1,-1);
	d[1]=1;
	f[1]=1;
  input(n);
  depth_search(1);
  print(n);
  return 0;
}

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;
}