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)
	t := 1
	for i := 1; i <= n; i++ {
		t = dfs(&g, &d, &f, i, t)
	}

	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>
#include <vector>
#include <queue>
#include <string>
#include <algorithm>
#include <utility>
#include <climits>
#include <cstring>
#include <cstdio>

using namespace std;
typedef long long int llg;

const int INF = 1000001000;
#define REP(var, count) for(int var=0; var<count; var++)

template <typename T>
using reverse_queue = std::priority_queue<T, std::vector<T>, std::greater<T> >;

template<typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val){
	std::fill( (T*)array, (T*)(array+N), val );
}

vector<int> rin[105];
pair<int, int> res[105];

int bfs(int a, int time) {
	if ( res[a].first != -1 ) { return time; }
	time++;
	res[a].first = time;
	for ( int r : rin[a] ) {
		time = bfs(r, time);
	}
	time++;
	res[a].second = time;
	return time;
}

int main(void) {
	int N;
	cin >> N;
	
	for(int i=1; i<=N; i++) {
		res[i].first = -1;
		res[i].second = -1;
		
		int U, K;
		cin >> U >> K;
		REP(j, K) {
			int x;
			cin >> x;
			rin[U].push_back(x);
		}
	}
	
	bfs(1, 0);
	
	for(int i=1; i<=N; i++) {
		printf("%d %d %d\n", i, res[i].first, res[i].second);
	}
}

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

int next(int u){
	for(int v = nt[u]; v < n; v++) {
		nt[u] = v + 1;
		if(M[u][v] == 1) 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);
	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 {
		   color[u] = BLACK;
		   S.pop();
		   f[u] = ++tt;
		}
	} 
}


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

C++: #include <iostream>

using namespace std;

int Time=0,d[101],f[101],v[101][101];
void Init()
{
    int i;
    for(i=1;i<=100;i++)
        d[i]=0;
}
void dfs(int cur,int n)
{
    int i;
    Time += 1;
    d[cur]=Time;
    for(i=1;i<=n;i++)
    {
        if(v[cur][i]==1 && d[i]==0)
            dfs(i,n);
    }
    Time += 1;
    f[cur] = Time;
}
int Find(int n,int d[])
{
    int flag=0,i;
    for(i=1;i<=n;i++)
        if(d[i]==0)
        {
            flag=i;
            break;
        }
    return flag;
}
int main()
{
    int n,m,k,i,j,flag;
    cin >> n;
    for(i=1;i<=n;i++)
        for(j=1;j<=n;j++)
            v[i][j]=0;
    for(i=1;i<=n;i++)
    {
        cin >> i >> k;
        for(j=1;j<=k;j++)
        {
            cin >> m;
            v[i][m]=1;
        }
    }
    Init();
    dfs(1,n);
    while(1)
    {
        flag = Find(n,d);
        if(flag == 0)
            break;
        else    dfs(flag,n);
    }
    for(i=1;i<=n;i++)
    {
        cout << i << ' ' << d[i] << ' ' << f[i] << endl;
    }
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
 
using ll = long long;
using ld = long double;
#define FOR(i, m, n) for (int i = (m); i < (n); i++)
#define FORR(i, m, n) for (int i = (m); i >= (n); i--)
#define REP(i, n) FOR(i, 0, (n))
#define REPR(i, n) FORR(i, (n) - 1, 0)
#define REP1(i, n) FOR(i, 1, (n) + 1)
#define REPS(c, s) for (char c : s)
#define ALL(c) (c).begin(), (c).end()
#define SORT(c) sort(ALL(c))
#define REV(c) reverse(ALL(c))
#define sz(v) (int)v.size()
#define endl '\n'
template<class T> inline bool chmin(T& a, T b) {if (a > b) {a = b; return true;} return false;}
template<class T> inline bool chmax(T& a, T b) {if (a < b) {a = b; return true;} return false;}
template<class T> inline void printv(vector<T>& v) {int n = sz(v); REP(i, n) cout << v[i] << (i == n - 1 ? endl : ' ');}
const int MOD = 1000000007;
const int INF = 1000000001;
const ll LINF = 1000000001000000001LL;
 
void solve();
 
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(numeric_limits<double>::max_digits10);
    solve();
    return 0;
}

void solve() {
    int n;
    cin >> n;
    vector<vector<int>> g(n, vector<int>());
    int u, k;
    REP(i, n) {
        cin >> u >> k;
        u--;
        int v;
        REP(j, k) {
            cin >> v;
            v--;
            g[u].emplace_back(v);
        }
    }

    vector<int> d(n, 0);
    vector<int> f(n, 0);
    int count = 0;
    function<void(int)> dfs = [&](int c) {
        if (d[c] == 0) d[c] = count;
        for (auto t : g[c]) {
            if (d[t] != 0) continue;
            count++;
            dfs(t);
        }
        count++;
        f[c] = count;
    };
    REP(i, n) if (d[i] == 0) {
        count++;
        dfs(i);
    }

    REP(i, n) cout << i + 1 << " " << d[i] << " " << f[i] << endl;
}

C++: #include <iostream>
#include <vector>
#include <stack>
#include <utility>
using namespace std;
int _time = 0;
stack<int> route;
void dfs(int root, vector<vector<bool>> &conn_mat, vector<bool> &accessed, vector<pair<int, int>> &result)
{
	accessed[root] = true;
	result[root].first = _time;
	int index;
	bool end = true;
	for (index = 0; index < conn_mat.size(); index++)
	{
		if (conn_mat[root][index] == true && accessed[index] == false)
		{
			_time++;
			result[index].first = _time;
			dfs(index, conn_mat, accessed, result);
			end = false;
		}
	}
	if (end)
	{
		_time++;
		result[root].second = _time;
		return;
	}
	_time++;
	result[root].second = _time;
	return;
}

int main()
{

	int n_node, index, n_cn, cn;
	cin >> n_node;
	vector<bool> vertex(n_node, false);
	vector<vector<bool>> conn_mat(n_node, vertex);
	vector<bool> &accessed = vertex;
	vector<pair<int, int>> result(n_node, make_pair(1, 0));
	while (n_node--)
	{
		cin >> index >> n_cn;
		while (n_cn--)
		{
			cin >> cn;
			conn_mat[index - 1][cn - 1] = true;
		}
	}
	bool end = false;
	while (!end) {
		_time++;
		int i = 0;
		while (accessed[i]) {
			i++;
		}
		dfs(i, conn_mat, accessed, result);
		end = true;
		for (auto acc : accessed) {
			end = end && acc;
		}
	}
	int i = 1;
	for (auto out : result) {
		cout << i << ' ' << out.first << ' ' << out.second << endl;
		i++;
	}
	return 0;
}

C++: /**
 * Depth first search.
 * start from node 1
 * 1) increment time 
 * 2) find non visited adjacent node
 * 3) if found move to that node.  d[v'] = time
 * 4) if not found. f[v] = time
 * 5) else end.
 * 5) go to 2.
 */

#include <iostream>
using namespace std;
const int N = 101;
int adj[N][N] = {0};
int d[N]={0};
int f[N]={0};
int t = 1;

void dfs(int n) {
	if (d[n]) return;
	d[n]=++t;
	int k = adj[n][0];
	for (int j=1;j<=k;j++) {
		dfs(adj[n][j]);
	}
	f[n]=++t;
}

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

	for (int i=1;i<=n;i++){
		dfs(i);
	}

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

	return 0;
}