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

static const int N = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int M[N][N] = {0}, color[N] = {0}, d[N], f[N], tt = 0, n;

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++) {
    if (color[u] == WHITE) {
      dfs_visit(u);
    }
  }

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

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

  cin >> n;
  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 <vector>
#include <iostream>
#include <set>
#include <cstdio>
#include <queue>
#include <cstdio>
#include <cstdlib>
#include <cassert>
#include <ctime>
#include <cmath>
#include <complex>
#include <algorithm>
#include <tuple>
#include <algorithm>
#include <limits>
#include <map>

using namespace std;

typedef long long ll;
typedef pair<int, int> P;
typedef tuple<int, int, int> T;

int d[110], f[110];
vector<int> g[110];
int t;
bool used[110];
void solve(int i) {
    if (used[i]) return;
    used[i] = true;
    t++;
    d[i] = t;
    for (int j: g[i]) {
        solve(j);
    }
    t++;
    f[i] = t;
}

int main() {
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
        int id, u;
        cin >> id >> u;
        for (int j = 0; j < u; j++) {
            int a;
            cin >> a;
            g[i].push_back(a-1);
        }
    }
    t = 0;
    fill_n(used, 110, false);
    for (int i = 0; i < n; i++) {
        solve(0);
    }
    for (int i = 0; i < n; i++) {
        printf("%d %d %d\n", i+1, d[i], f[i]);
    }
    return 0;
}

C++: #include <iostream>
using namespace std;
const int MAXn=100;

int n,M[MAXn][MAXn]={0},col[MAXn];//color:0=white,1=gray,2=brack
int d[MAXn],f[MAXn],t;

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

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

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

C++: #include<iostream>
#include<stack>
using namespace std;
static const int N = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

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

// u に隣接する v を番号順に取得
int next(int u) {
  for ( int v = nt[u]; v < n; v++ ) {
    nt[u] = v + 1;
    if ( M[u][v] ) return v;
  }
  return -1;
}

// スタックを用いた深さ優先探索
void dfs_visit(int r) {
  for ( int i = 0; i < n; i++ ) nt[i] = 0;

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

  while ( !S.empty() ) {
    int u = S.top();
    int v = next(u);
    if ( v != -1 ) {
      if ( color[v] == WHITE ) {
        color[v] = GRAY;
        d[v] = ++tt;
        S.push(v);
      }
    } else {
      S.pop();
      color[u] = BLACK;
      f[u] = ++tt;
    }
  }
}

void dfs() {
  // 初期化
  for ( int i = 0; i < n; i++ ) {
    color[i] = WHITE;
    nt[i] = 0;
  }
  tt = 0;

  // 未訪問の u を始点として深さ優先探索
  for ( int u = 0; u < n; u++ )
    if ( color[u] == WHITE ) dfs_visit(u);
  for ( int i = 0; i < n; i++ )
    cout << i+1 << " " << d[i] << " " << f[i] << endl;
}

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

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

  dfs();

  return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

int n,t;
vector<vector<int>> M(101,vector<int>(101,0));
vector<int> color(101,0);
vector<int> d(101,0),f(101,0);

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

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

    t=0;
    for(int i=1;i<n+1;i++){
        if(color[i]==0){
            dfs(i);
        }
    }

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

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

struct Node {
	int ID;
	int d;
	int f;
	bool visited;
	bool operator<(const Node& rhs) {return this->ID < rhs.ID;}
	bool operator>(const Node& rhs) {return this->ID > rhs.ID;}
	bool operator<=(const Node& rhs) {return this->ID <= rhs.ID;}
	bool operator>=(const Node& rhs) {return this->ID >= rhs.ID;}
	bool operator==(const Node& rhs) {return this->ID == rhs.ID;}
	bool operator!=(const Node& rhs) {return this->ID != rhs.ID;}
};

int step = 1;

void DFS(std::vector<int>* adjlist, Node* nodes, int v)
{
	nodes[v].visited = true;
	nodes[v].d = step;
	step++;
	
	for (int i=0; i<adjlist[v].size(); i++) {
		int id = adjlist[v][i];
		if (!nodes[id].visited) DFS(adjlist, nodes, id);
	}
	
	nodes[v].f = step;
	step++;
}

int main()
{
	int n; std::cin >> n;
	
	std::vector<int>* adjlist = new std::vector<int>[n];
	Node* nodes = new Node[n];
	
	for (int i=0; i<n; i++) nodes[i].visited = false;
	
	for (int i=0; i<n; i++) {
		int x;
		int deg;
		std::cin >> x >> deg;
		nodes[i].ID = x-1;
		for (int j=0; j<deg; j++) {
			int y;
			std::cin >> y;
			adjlist[x-1].push_back(y-1);
		}
	}
	
	std::sort(nodes, nodes + n);
	
	for (int i=0; i<n; i++) {
		if (!nodes[i].visited) DFS(adjlist, nodes, i);
	}
	
	for (int i=0; i<n; i++) {
		std::cout << nodes[i].ID + 1 << " " << nodes[i].d << " " << nodes[i].f << std::endl;
	}
	
	delete[] adjlist;
	delete[] nodes;
	
	return 0;
}

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);

  dfs(1, a, d, f, visited);

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