Go: #include <bits/stdc++.h>
using namespace std;
static const int WHITE = 0;
static const int GRAY  = 1;
static const int BLACK = 2;
static const int N     = 100;

int n, tt;
vector<vector<int>> M(N, vector<int>(N));
vector<int> color(N), d(N), f(N);

void dfs_visit(int u) {
  color[u] = GRAY;
  d[u]     = ++tt;
  for (int 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() {
  tt = 0;

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

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

  dfs();
}

C++: #include <set>
#include <map>
#include <list>
#include <queue>
#include <stack>
#include <cmath>
#include <ctype.h>
#include <ctime>
#include <cstdio>
#include <vector>
#include <string>
#include <bitset>
#include <cctype>
#include <cstdlib>
#include <cstring>
#include <utility>
#include <numeric>
#include <complex>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <cassert>
#include <iostream>
#include <iterator>
#include <algorithm>

using namespace std;
#define MAX 100
#define WHITE 1
#define GRAY 2
#define BLACK 3

int n;
int graph[MAX][MAX];
stack<int> st;
int *d,*f,*v;
int *color;
int tm = 0;

int next(int k){
	for(int i = v[k];i < n;i++){
		v[k]++;
		if(color[i] == WHITE && graph[k][i] == 1) return i;
	}
	return -1;
}

void dfs(int k){
	for(int i = 0;i < n;i++) v[i] = 0;

	st.push(k);
	d[k] = ++tm;
	color[k] = GRAY;

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


int main(){
	cin >> n;
	//?????????
	color = new int[n];
	d = new int[n];
	f = new int[n];
	v = new int[n];
	for(int i = 0;i < n;i++){
		color[i] = WHITE;
		d[i] = 0;
		f[i] = 0;
		for(int j = 0;j < n;j++){
			graph[i][j] = 0;
		}
	}
	//data input
	for(int i = 0;i < n;i++){

		int t,k,p;

		cin >> t >>  k;
		for(int j = 0;j < k;j++){
			cin >> p;
			p--;
			graph[i][p] = 1;
		}
	}
	for(int i = 0;i < n;i++){if(color[i] == WHITE) dfs(i);}
	for(int i = 0;i < n;i++){
		cout << i+1 << " " << d[i] << " " << f[i] << endl;
	}
	return 0;
}

C++: #include<iostream>
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
using namespace std;
int G[100][100] = {};
int time = 0;
typedef struct ANS
{
	int id, t, e;
	bool done;
};

void rec(ANS a[],int t)
{
	::time++;
	a[t].t = ::time;
	a[t].done = true;
	FOR(i, 0, 100)
	{
		if (G[t][i] == 1 && a[i].done == false)
		{
			rec(a, i);
		}
	}
	::time++;
	a[t].e = ::time;
}

int main()
{
	ANS ans[101];
	int n;
	cin >> n;
	FOR(i, 0, n)
	{
		ans[i].id = i + 1;
		ans[i].done = false;
		int u, m;
		cin >> u >> m;
		FOR(j, 0, m)
		{
			int l;
			cin >> l;
			G[u - 1][l - 1] = 1;
		}
	}
	rec(ans, 0);
	FOR(i, 0, n)
	{
		cout << ans[i].id << " " << ans[i].t << " " << ans[i].e << endl;
	}
	return 0;
}

C++: #include<iostream>
using namespace std;
int visit[101],d[101],f[101],t;
int n,M[101][101];

static const int WHITE=0;
static const int GRAY=1;

void dfs(int u){
  visit[u]=GRAY;
  d[u]=++t;
  for(int v=0;v<n;v++){
    if(M[u][v]==0) continue;
    if(visit[v]==WHITE){
      dfs(v);
    }
  }
  f[u]=++t; 
}

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

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

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

stack<int> S;
int n, x[10000][10000], a, b, c, d, _time=2;
int y[10000][3];

int main() {
	cin >> n;
	for (int i = 1; i <= n; i++) {
		cin >> b >> c;
		for (int j = 1; j <= c; j++) {
			cin >> d;
			x[i][d] = 1;
		}
	}
	S.push(1);
	y[1][1] = 1;
	while (!S.empty()) {
		a = S.top();
		for (int i = 1; i <= n; i++) {
			if (x[a][i] == 1 && y[i][0] == 0) {
				y[i][0] = 1;
				y[i][1] = _time;
				S.push(i);
				goto Exit;
			}
		}
		S.pop();
		y[a][2] = _time;
	Exit:;
		_time++;
	}
	for (int i = 1; i <= n; i++) {
		cout << i << ' ' << y[i][1] << ' ' << y[i][2] << endl;
	}
	return 0;
}

C++: // -*- mode:c++; coding:utf-8; c-basic-offset:2; -*-
// ALDS1_11_B: Depth First Search

#include <algorithm>
#include <cstdio>
#include <stack>
#include <utility>

using uint = unsigned int;

class Graph {
  const uint n_;
  uint* const g_;
  std::pair<int, int>* const visited_;
  uint time_;
  
public:
  Graph(uint n) : n_(n),
                  g_(new uint[(n_*n_)]),
                  visited_(new std::pair<int, int>[n_])
  {
    std::fill(g_, g_+(n_*n_), 0u);
  }

  ~Graph()
  {
    delete[] g_;
    delete[] visited_;
  }
  
  uint* operator [](uint i) const { return g_+(n_*i); }

  std::pair<int, int>* visited() const { return visited_; }

  void dfs()
  {
    init_visited();
    for (auto i = 0u; i < n_; ++i) {
      inner_dfs(i);
    }
  }

private:
  void init_visited()
  {
    time_ = 0u;
    for (auto i = 0u; i < n_; ++i) {
      visited_[i].first = -1;
    }
  }

  void inner_dfs(uint i)
  {
    if (visited_[i].first != -1) {
      return;
    }
    visited_[i].first = time_++;
    for (auto j = 0u; j < n_; ++j) {
      auto k = (*this)[i][j];
      if (k) {
        inner_dfs(j);
      }
    }
    visited_[i].second = time_++;
  }
};

int main()
{
  uint n;
  std::scanf("%u", &n);

  Graph g(n);

  uint u, k, v;
  for (auto i = 0u; i < n; ++i) {
    std::scanf("%u %u", &u, &k);
    for (auto j = 0u; j < k; ++j) {
      std::scanf("%u", &v);
      g[u-1][v-1] = 1;
    }
  }

  g.dfs();
  auto visited = g.visited();
  for (auto i = 0u; i < n; ++i) {
    std::printf("%u %d %d\n", i+1, visited[i].first+1, visited[i].second+1);
  }
}

// eof

C++: #define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <stdio.h>
#include <list>
#define black 0
//#define red 1
#define white -1
#define maxn 110
using namespace std;

int tot = 0;
int book[maxn] = {}, t[maxn][2] = {};
list<int> map[maxn];

void dfs(int u)
{
	if (book[u] == white) return; 
	else
		if (book[u] == black)
		{
			t[u][0] = ++tot;
			for (list<int>::iterator it = map[u].begin(); it != map[u].end(); it++)
				dfs(*it-1);
			book[u] = white;
			t[u][1] = ++tot;
		}
	return;
}
int main()
{
	int n;
	scanf("%d", &n);
	for (int i = 0; i < n; i++)
	{
		int u,k,v;
		scanf("%d%d", &u,&k);
		u--;
		for (int i = 0; i < k; i++)
		{
			scanf("%d", &v);
			map[u].push_back(v);
		}
	}
	dfs(0);
	for (int i = 0; i < n; i++)
	{
		printf("%d %d %d\n", i + 1, t[i][0], t[i][1]);
	}
	return 0;
}

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

int n,M[105][105],d[105],f[105],tt,P[105],nt[105];

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);
	P[r]=1;
	tt++;
	d[r]=tt;
	while(s.size()!=0){
		int u= s.top();
		int v=next(u);
		if(v!=-1){
			if(P[v]==0){
				P[v]=1;
				tt++;
				d[v]=tt;
				s.push(v);
			}
		}
		else{
			P[u]=2;
			tt++;
			f[u]=tt;
			s.pop();
		}
	}
}

void dfs(){
	for(int i=0;i<105;i++){
		d[i]=f[i]=P[i]=0;
	}
	tt=0;
	for(int i=0;i<n;i++){
		if(P[i]==0){
			dfs_visit(i);
		}
	}
	for(int i=0;i<n;i++){
		printf("%d %d %d\n",i+1,d[i],f[i]);
	}
}

int main() {
	cin>>n;
	int u,k,v;
	for(int i=0;i<105;i++){
		for(int j=0;j<105;j++){
			M[i][j]=0;
		}
	}
	for(int i=0;i<n;i++){
		cin>> u>>k;
		u--;
		for(int j=0;j<k;j++){
			cin>>v;
			v--;
			M[u][v]=1;
		}
	}
	dfs();
	return 0;
}