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<stack>
using namespace std;

enum Status {WHITE, GRAY, BLACK};

stack<int> stc;
Status *status;
int *discovered, *finished;
vector<vector<int> > a;
int n, timer;

void dfs(int i){
        if(status[i]==BLACK) return;
        if(status[i]==WHITE){
                discovered[i] = ++timer;
                status[i] = GRAY;
        }
        stc.push(i);

        for(int j=0;j<a[i].size();j++) dfs(a[i][j]);

        if(status[i]==GRAY){
                finished[i] = ++timer;
                status[i] = BLACK;
        }
        stc.pop();
}

int main(){

        cin>>n;
        a = vector<vector<int> >(n, vector<int>());
        status = new Status[n];
        discovered = new int[n];
        finished = new int[n];

        int m, k, r;
        for(int i=0;i<n;i++){
                cin>>r;
                cin>>m;
                for(int j=0;j<m;j++){
                        cin>>k;
                        a[r-1].emplace_back(k-1);
                }
        }
        for(int i=0;i<n;i++) status[i] = WHITE;

        timer = 0;
        dfs(0);


        for(int i=0;i<n;i++){
                cout<<i+1<<" "<<discovered[i]<<" "<<finished[i]<<endl;
        }
        return 0;
}

C++: #include <iostream>
#include <iomanip>
#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <functional>
#include <sstream>
#include <string>
#include <utility>
#include <map>
#include <memory>
#include <set>
#include <vector>
#include <deque>
#include <list>
#include <stack>
#include <queue>

using namespace std;

class DFS
{
public:
  int n;
  int solve();
  int dfs( int v, int t, vector<vector<int>>& adj, vector<int>& d, vector<int>& f );
};

int DFS::dfs( int v, int t, vector<vector<int>>& adj, vector<int>& d, vector<int>& f )
{
  if ( d[v] )
    return t;
  else
    d[v] = t++;

  for ( auto i = 1; i <= n; ++i )
    if ( adj[v][i] )
      t = dfs( i, t, adj, d, f );

  f[v] = t;

  return ++t;
}

int DFS::solve()
{
  cin >> n;

  vector<vector<int>> adj(n+1, vector<int>(n+1, 0));
  vector<int> d(n+1,0);
  vector<int> f(n+1,0);

  for ( auto i = 0; i < n; ++i )
    {
      int x, k;
      cin >> x;
      cin >> k;
      for ( auto j = 0; j < k; ++j )
        {
          int y;
          cin >> y;
          adj[x][y] = 1;
        }
    }

  int t = 1;
  
  for ( auto i = 1; i <= n; ++i )
    t = dfs( i, t, adj, d, f );

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

int main()
{
  DFS d;

  d.solve();

  return 0;
}

C++: // ALDS1_11_B
#include <iostream>
#include <vector>
using namespace std;

void DFS(vector<vector<int> > A, vector<int> &d, vector<int> &f, vector<int> &visit, int &t, int v){
	
	visit[v] = 1;
	d[v] = t++;

	for(int i=0;i<A[v].size();i++)
		if((A[v][i] == 1) && (visit[i] == 0))
			DFS(A, d, f, visit, t, i);

	f[v] = t++;
}

int main(){
	int n, u, k, t=1;
	vector<vector<int> > A;
	vector<int> d, f, visit;

	cin>>n;
	A.resize(n);
	d.resize(n);
	f.resize(n);
	for(int i=0;i<n;i++){
		A[i].resize(n);
		visit.push_back(0);
	}

	for(int i=0;i<n;i++)
		for(int j=0;j<n;j++)
			A[i][j] = 0;

	for(int i=0;i<n;i++){
		cin>>u>>k;
		int v;
		
		for(int j=0;j<k;j++){
			cin>>v;
			A[u-1][v-1] = 1;
		}
	}

	DFS(A, d, f, visit, t, 0);
	for(int i=0;i<n;i++)
		cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;

	return 0;
}

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

int r[101][101];
int d[101], f[101], num, visit[101], p=0;

void dfs(int n){
    if(!visit[n]){
        visit[n]++;
        d[n] = ++p;
        for(int i=1; i<num+1; i++)
            if(r[n][i]) dfs(i);
        f[n] = ++p;
    }
}

int main(void){
    int u, k, v;
    cin >> num;
    for(int i=0; i<num; i++){
        cin >> u >> k;
        for(int j=0; j<k; j++){
            cin >> v;
            r[u][v]++;
        }
    }
    for(int i=1; i<num+1; i++){
        if(!visit[i]) dfs(i);
    }
    for(int i=1; i<num+1; i++)
        cout << i << " " << d[i] << " " << f[i] << endl;
}

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

using namespace std;

int N,k[1000];
int v[1000][1000];
int found[1000] = {0},ended[1000] = {0};
int keep;
int checking=0;

void dfs(int cur);

int main() {
	cin >> N;
	for(int i=1;i<N+1;i++) {
		cin >> keep >> k[i];
		for(int j=1;j<k[i]+1;j++) {
			cin >> v[i][j];

		}
	}
	dfs(1);
	
	for(int i=1;i<N+1;i++) {
		cout << i << " " << found[i] << " " << ended[i] << endl;
	}
	

}

void dfs(int cur) {
	
	if(!found[cur]) {
		checking++;
		//cerr << "visiting: " << cur << " " << "time: " << checking << endl;
		found[cur] = checking;
	}
	for(int dst=1;dst<N+1;dst++) {
		bool flag = false;
		for(int i=1;i<k[cur]+1;i++) {
			if(v[cur][i] == dst) flag = true;
		}
		if(flag) dfs(dst);
	}
	if(!ended[cur]) {
		checking++;
		//cerr << "ended: " << cur << " " << "time: " << checking << endl;
		ended[cur] = checking;
	}
}

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

int main(){
    unsigned long n;
    std::cin >> n;

    std::vector<std::vector<unsigned long>> edges(n);
    for(auto&& i : edges){
        unsigned long u;
        std::cin >> u;
        unsigned long k;
        std::cin >> k;
        i = std::vector<unsigned long>(k);
        for(auto&& j : i){
            std::cin >> j;
            --j;
        }
    }

    std::vector<unsigned long> d(n), f(n);

    [dfs_impl = [&edges, &d, &f](auto func, unsigned long now, unsigned long& t) -> void {
        d[now] = ++t;
        for(const auto& i : edges[now])if(!d[i])func(func, i, t);
        f[now] = ++t;
    }, &n, &d]{
        unsigned long t{0};
        for(unsigned long i{0}; i < n; ++i)if(!d[i])dfs_impl(dfs_impl, i, t);
    }();

    for(unsigned long i{0}; i < n; ++i)std::cout << i + 1 << " " << d[i] << " " << f[i] << std::endl;

    return 0;
}