Go: package main

import (
	"fmt"
)

func main() {
	var n int
	fmt.Scan(&n)
	g := make([][]int, n+1)
	for i := 0; i < n; i++ {
		var u,k int
		fmt.Scan(&u)
		fmt.Scan(&k)
		g[u] = make([]int, k)
		for j := 0; j < k; j++ {
			fmt.Scan(&g[u][j])
		}
	}

	d := make([]int, n+1)
	f := make([]int, n+1)
	dfs(&g, &d, &f, 1, 1)

	for i := 1; i <= n; i++ {
		fmt.Printf("%d %d %d\n", i, d[i], f[i])
	}
}

func dfs(g *[][]int, d *[]int, f *[]int, id int, t int) int {
	if (*d)[id] > 0 {
		return t
	}
	(*d)[id] = t
	t += 1
	for i := 0; i < len((*g)[id]); i++ {
		t = dfs(g, d, f, (*g)[id][i], t)
	}
	(*f)[id] = t
	return t+1
}

C++: // 深さ優先探索
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<stack>
#include<algorithm>
#include<iostream>
#include<cmath>
#include<vector>

using namespace std;

#define MAX_N 100
// 値の定義
const int EXIST = 1;
const int NO_EXIST = 0;

const int WHITE = 0;// 未訪問
const int GRAY = 1; // 訪問中
const int BLACK = 2;// 訪問完了

// グラフ情報を保持する配列
int ary_graph[MAX_N + 1][MAX_N + 1];

// 各頂点の訪問状態を保持する配列
int color[MAX_N + 1];

// 発見時刻と完了時刻を保持する構造体
typedef struct
{
    int start_time;
    int end_time;
}SearchTime;

SearchTime st_SearchTime[MAX_N + 1];
int search_T = 0;

void depthFirstSearch(int now_vertex, int vertex_num);

int main(void)
{
    int n, u, num, v_num;

    for(int i = 0; i < MAX_N + 1; i++)
    {
        color[i] = WHITE;

        for(int j = 0; j < MAX_N + 1; j++)
        {
            // 配列の初期化
            ary_graph[i][j] = NO_EXIST;
        }
    }

    cin >> n;

    for(int i = 0; i < n; i++)
    {
        cin >> u;
        cin >> num;

        // 0オリジンにする
        u--;

        for(int j = 0; j < num; j++)
        {
            // 隣接点を記憶する
            cin >> v_num;

            // 0オリジンにする
            v_num--;
            ary_graph[u][v_num] = EXIST;
        }
    }

    // 深さ優先探索を実施
    for(int i = 0; i < n; i++)
    {
        if( color[i] == WHITE )
        {
            depthFirstSearch(i, n);
        }
    }

    // 結果の表示
    for(int i = 0; i < n; i++)
    {
        printf("%d %d %d\n", i + 1, st_SearchTime[i].start_time, st_SearchTime[i].end_time);
    }

    return 0;
}

// 深さ優先探索を実施する関数
// now_vertex : 現在の頂点のNo.
// next_vertex : 次の頂点のNo.
// vertex_num : グラフの頂点数
void depthFirstSearch(int now_vertex, int vertex_num)
{
    // 訪問中
    color[now_vertex] = GRAY;

    // 発見時刻の設定
    search_T++;
    st_SearchTime[now_vertex].start_time = search_T;

    for(int i = 0; i < vertex_num; i++)
    {
        if( color[i] == WHITE
            && ary_graph[now_vertex][i] == EXIST )
        {
            depthFirstSearch(i, vertex_num);
        }
    }

    // 訪問完了
    color[now_vertex] = BLACK;

    // 終了時刻の設定
    search_T++;
    st_SearchTime[now_vertex].end_time = search_T;

    return;
}

C++: #include<iostream>
#include<algorithm>
#include<cstdio>
#include<stack>

#define N 100

using namespace std;

int n;
int unvisited=0,visited=1,comp_visited=2;
int M[N][N],state[N],nt[N];
int d[N],f[N],t;

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

void dfs_visit(int r){
	for(int i=0;i<n;i++){
		nt[i]=0;
	}
	stack<int> s;
	s.push(r);
	state[r]=visited;
	t++;
	d[r]=t;
	
	while(!s.empty()){
		int u=s.top();
		int v=next(u);
		if(v!=-1){
			if(state[v]==unvisited){
				state[v]=visited;
				t++;
				d[v]=t;
				s.push(v);
			}
		}
		else{
			s.pop();
			state[u]=comp_visited;
			t++;
			f[u]=t;
		}
	}
}

void dfs(){
	for(int i=0;i<n;i++){
		state[i]=unvisited;
		nt[i]=0;
	}
	t = 0;
	for(int u=0;u<n;u++){
		if(state[u]==unvisited) dfs_visit(u);
	}
	for(int i=0;i<n;i++){
		printf("%d %d %d\n",i+1,d[i],f[i]);
	}
}

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

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

int now_time = -1, time_stamp_d[101]{}, time_stamp_f[101]{};
int vertices_num;
std::vector<int> dest[101];
void search(int);

int main()
{
	int vertex_tmp, dest_num, dest_tmp;

	std::cin >> vertices_num;
	for (int i = 1; i <= vertices_num; ++i)
	{
		std::cin >> vertex_tmp >> dest_num;
		for (int j = 0; j < dest_num; ++j)
		{
			std::cin >> dest_tmp;
			dest[vertex_tmp].push_back(dest_tmp);
		}
		dest[0].push_back(i);
	}
	
	search(0);

	for (int i = 1; i <= vertices_num; ++i)
	{
		std::cout << i << " " << time_stamp_d[i] << " " << time_stamp_f[i] << std::endl;
	}

	return 0;
}

void search(int now_place)
{
	time_stamp_d[now_place] = ++now_time;
	for (auto e : dest[now_place])
	{
		if (time_stamp_d[e]) continue;
		search(e);
	}
	time_stamp_f[now_place] = ++now_time;
	return;
}

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

#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() {
  scanf("%d", &n);
  for ( int i = 0; i < n; i++ ) {
    for ( int j = 0; j < n; j++ ) {
      M[i][j] = 0;
    }
  }

  for ( int i = 0; i < n; i++ ) {
    int a, b;
    cin >> a >> b;
    a--;
    for ( int j = 0; j < b; j++ ) {
      int c;
      cin >> c;
      c--;
      M[a][c] = 1;
    }
  }

  dfs();

  return 0;
}

C++: #include <cstdio>
#include <iostream>
#include <cmath>
#include <ctype.h>
#include <string>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <cstdlib>
#include <map>
#include <queue>
#include <utility>
#include <vector>
#include <set>
#include <list>
#include <cstring>
#include <stack>

using namespace std;

#define mod 1000000007

int n;
int d[101], v[101];
int graph[101][101] = {};

int solve(int k, int cnt)
{
	d[k] = cnt;
	int nowcnt = cnt;
	for(int i = 0; i < n; i++){
		if(d[i] < 0 && graph[k][i] > 0) nowcnt = solve(i, nowcnt + 1);
	}
	return v[k] = nowcnt + 1;
}

int main()
{
	cin >> n;
	for(int i = 0; i < n; i++){
		d[i] = -1;
		v[i] = -1;
		int u, k;
		cin >> u >> k;
		u--;
		for(int j = 0; j < k; j++){
			int v;
			cin >> v;
			v--;
			graph[u][v] = 1;
		}
	}
	int nowcnt = 1;
	for(int i = 0; i < n; i++){
		if(d[i] < 0) nowcnt = solve(i, nowcnt) + 1;
	}
	for(int i = 0; i < n; i++){
		cout << i + 1 << " " << d[i] << " " << v[i] << endl;
	}
}

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

using namespace std;

int curTime = 1;
void dfs(int cur, const vector<vector<bool> >& a, vector<int>& d, vector<int>& f, vector<bool>& visited){
  visited[cur] = true;
  d[cur] = curTime;
  curTime++;
  // cerr << "visiting [" << cur << "], time = " << curTime << endl;

  for(int dst = 1; dst <= a.size(); dst++){
    if(a[cur][dst] && !visited[dst]) {// cur????????¶??????????????????????????????
      dfs(dst, a, d, f, visited);
    }
  }
  f[cur] = curTime;
  curTime++;
  return;
}

int main(){
  int n;
  cin >> n;
  vector<vector<bool> > a(n+1, vector<bool>(n+1, false));
  for(int i = 1; i <= n; i++){
    int u;
    cin >> u;
    int k;
    cin >> k;
    for(int j = 0; j < k; j++){
      int v;
      cin >> v;
      a[i][v] = true;
    }
  }

  vector<bool> visited(n+1, false);
  vector<int> d(n+1), f(n+1);

  for(int i = 1; i <= n; i++){
    if(!visited[i]){
      dfs(i, a, d, f, visited);
    }
  }

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