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<cstdio>
#include<cstring>
#include<algorithm>
#include<vector>
#include<queue>
using namespace std;
 
int find_t[101],end_t[101];
vector<queue<int> > vec(101);
int flag[101];
int t=1;
 
void DFS(int);
void Print();
 
int main(int argc,char* argv[]){
  int n,id,cnt,x;
   
  memset(find_t,255,sizeof(find_t));
  memset(end_t,0,sizeof(end_t));
  memset(flag,0,sizeof(flag));
 
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>id>>cnt;
    flag[id]=0;
    queue<int> tmp;
    for(int l=0;l<cnt;l++){
      cin>>x;
      tmp.push(x);
    }
    vec[id]=tmp;
  }
   
  for(int i=1;i<=n;i++){
    if(flag[i]==0)
      DFS(i);
  }
  Print();
   
  return 0;
}
 
void DFS(int p){
  if(flag[p]==0){
    find_t[p]=t++;
    flag[p]=1;
  }
  else
    return;
     
  queue<int> tmp=vec[p];
  while(!tmp.empty()){
    DFS(tmp.front());
    tmp.pop();
  }
 
  end_t[p]=t++;
}
 
void Print(){
  for(int i=1;i<=100;i++){
    if(find_t[i]!=-1)
      printf("%d %d %d\n",i,find_t[i],end_t[i]);
  }
}

C++: #include<iostream>
#include<cstdio>
#define WHITE 0
#define GRAY 1
#define BLACK 2

using namespace std;

int n, M[101][101];
int color[101], count1[101], count2[101], t;

void dfs_visit(int u) {
	int v;
	color[u] = GRAY;
	t++;
	count1[u] = t;
	for (v = 1; v <= n; v++) {
		if (M[u][v] == 0) {
			continue;
		}

		if (color[v] == WHITE) {
			dfs_visit(v);
		}
	}
	color[u] = BLACK;
	t++;
	count2[u] = t;
}

void dfs() {
	int u;
	for (u = 1; u <= n; u++) {
		color[u] = WHITE;
		t = 0;
	}
	for (u = 1; u <= n; u++) {
		if (color[u] == WHITE) {
			dfs_visit(u);
		}
	}
	for (u = 1; u <= n; u++) {
		printf("%d %d %d\n", u, count1[u], count2[u]);
	}
}

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

	for (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;
		for (j = 0; j < k; j++) {
			cin >> v;
			M[u][v] = 1;
		}
	}

	dfs();

	return 0;
}

/*
6
1 2 2 3
2 2 3 4
3 1 5
4 1 6
5 1 6
6 0
*/

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

const int MAX_N = 100;
vector<int> G[MAX_N];
int d[MAX_N], f[MAX_N];
bool used[MAX_N];

int stamp;

void dfs(const int v) {
    d[v] = stamp++;
    used[v] = true;
    for(int i = 0; i < (int)G[v].size(); i++) {
        int u = G[v][i];
        if(used[u] == false) dfs(u);
    }
    f[v] = stamp++;
}

int main() {
    int N; cin >> N;
    for(int i = 0; i < N; i++) {
        int u, k; cin >> u >> k; u--;
        while(k--) {
            int v; cin >> v; v--;
            G[u].push_back(v);
        }
        sort(G[u].begin(), G[u].end());
    }

    fill(used, used + N, false);
    stamp = 1;
    dfs(0);

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

C++: #include <iostream>
#include <algorithm>
#include <stack>
#include <queue>
#include <vector>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>

using namespace std;

struct Node {
	int k, d, f;
	vector<int> v;
};

#define MAX_N 100

Node node[MAX_N + 1];
int _d, _f;

void dfs(int u) {
	if (node[u].d == 0) node[u].d = _d++;
	for (int i = 0; i < node[u].k; ++i)
		dfs(node[u].v[i]);
	if (node[u].f == 0) node[u].f = _f++;
}

int main() {
	int n;
	cin >> n;
	for (int i = 0; i < n; ++i) {
		int u;
		cin >> u;
		cin >> node[u].k;
		for (int j = 0; j < node[u].k; ++j) {
			int v;
			cin >> v;
			node[u].v.push_back(v);
		}
		node[u].d = node[u].f = 0;
	}
	_d = 1;
	_f = n + 1;
	dfs(1);
	for (int i = 1; i <= n; ++i)
		cout << i << " " << node[i].d << " " << node[i].f << endl;
	return 0;
}

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

struct Node{
  vector<int> AJ;
  bool visit;
  int d, f;
};

Node G[101];
int t = 0;

void dfs(int idx){
  G[idx].visit = true;
  G[idx].d = ++t;
  for(int i = 0; i < G[idx].AJ.size(); i++){
    if(!G[G[idx].AJ[i]].visit) dfs(G[idx].AJ[i]);
  }
  G[idx].f = ++t;
}

int main(){
  int n, u, k, v;
  cin >> n;
  for(int i = 0 ; i < 101; i++) G[i].visit = false;
  for(int i = 0; i < n; i++){
    cin >> u >> k;
    for(int j = 0; j < k; j++){
      cin >> v;
      G[u].AJ.push_back(v);
    }
  }
  for(int i = 1; i <= n; i++) if(!G[i].visit) dfs(i);
  for(int i = 1; i <= n; i++) cout << i << " " << G[i].d << " " << G[i].f << endl;
  return 0;
}

C++: 
#include<iostream>

using namespace std;

const int MAX = 100;

void search(bool graph[MAX][MAX], int find[], int done[], int n, int u,int& count) {
	count++;
	find[u] = count;
	cout << u << endl;
	for (int i = 0; i < n; i++) {
		if (graph[u][i] && find[i] == 0) {
			search(graph, find, done, n, i, count);
		}
	}
	count++;
	done[u] = count;
}

int main() {
	bool check[MAX] = { false };
	int find[MAX] = { 0 };
	int done[MAX] = { 0 };
	bool graph[MAX][MAX] = { {false} };
	int N;

	cin >> N;
	for (int i = 0; i < N; i++) {
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			int temp;
			cin >> temp;
			graph[u - 1][temp - 1] = true;
		}
	}

	int count = 0;
	for (int i = 0; i < N; i++) {
		if (find[i] == 0) {
			search(graph, find, done, N, 0, count);
		}
	}

	for (int i = 0; i < N; i++) {
		cout << i + 1 << " " << find[i] << " " << done[i] << endl;
	}

	return 0;
}