Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)
var depth [101]int
var finish [101]int
var d [101]int
var n, time int

func nextInt() int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return i
}
func visit(graph [][]int, u int) {
	depth[u] = 1
	time++
	d[u] = time
	for i := 0; i < n; i++ {
		if graph[u][i] == 1 {
			if depth[i] == 0 {
				visit(graph, i)
			}
		}
	}
	depth[u] = 2
	time++
	finish[u] = time
}
func main() {
	sc.Split(bufio.ScanWords)

	n = nextInt()
	graph := make([][]int, n)
	for i := 0; i < n; i++ {
		graph[i] = make([]int, n)
	}
	for i := 0; i < n; i++ {
		s := nextInt()
		t := nextInt()
		if t == 0 {
			continue
		}
		for i := 0; i < t; i++ {
			u := nextInt()
			graph[s-1][u-1] = 1
		}
	}
	for i := 0; i < n; i++ {
		if depth[i] == 0 {
			visit(graph, i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, d[i], finish[i])
	}
}

C++: #include <iostream>
#include <fstream>
#include <cstdio>
#include <cmath>
#include <vector>
#include <string>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <deque>
#include <bitset>
#include <algorithm>
#include <complex>
#include <array>
#include <iomanip>
using namespace std;

#define REP(i,n) for(int i=0; i<n; ++i)
#define FOR(i,a,b) for(int i=a; i<=b; ++i)
#define FORR(i,a,b) for (int i=a; i>=b; --i)
#define ALL(c) (c).begin(), (c).end()

typedef long long ll;
typedef vector<int> VI;
typedef vector<ll> VL;
typedef vector<long double> VD;
typedef vector<VI> VVI;
typedef vector<VL> VVL;
typedef vector<VD> VVD;
typedef pair<int,int> P;
typedef pair<ll,ll> PL;

template<typename T> void chmin(T &a, T b) { if (a > b) a = b; }
template<typename T> void chmax(T &a, T b) { if (a < b) a = b; }

int in() { int x; scanf("%d", &x); return x; }
ll lin() { ll x; scanf("%lld", &x); return x; }
#define INF 1LL<<60

int timestamp = 1;

void dfs(int from, vector< vector<int> >& edges, vector<int>& d, vector<int>& f) {
    if(d[from] > 0) return;
    d[from] = timestamp++;
    for(int next: edges[from]) {
        if(d[next] == 0)
            dfs(next, edges, d, f);
    }
    f[from] = timestamp++;
}

int main() {
    int N;
    cin >> N;
    vector<vector<int> > edges(N+1);
    REP(i, N) {
        int u, k;
        cin >> u >> k;
        edges[u].resize(k);
        REP(j, k) cin >> edges[u][j];
        sort(ALL(edges[u]));
    }

    vector<int> d(N+1), f(N+1);
    FOR(i, 1, N)
        dfs(i, edges, d, f);
    FOR(i, 1, N) {
        cout << i << " " << d[i] << " " << f[i] << endl;
    }
    return 0;
}

C++: #include <stdio.h>
#include <iostream>
#include <utility>
#include <algorithm>
#include <math.h>
#include <vector>
#include <list>

using namespace std;
int n;
list<int> adj[101];
int d[101] = {};
int f[101] = {};

void DFS(int v)
{
    static int num = 1;
    d[v] = num++;
    while (!adj[v].empty())
    {
        if (d[adj[v].front()] == 0)
            DFS(adj[v].front());
        adj[v].pop_front();
    }
    f[v] = num++;
}

void print()
{
    for (int i = 1; i <= n; i++)
    {
        printf("%d %d %d\n", i, d[i], f[i]);
    }
}

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

    for (int i = 0; i < n; i++)
    {
        cin >> u >> k;
        while (k > 0)
        {
            cin >> v;
            adj[u].push_back(v);
            k--;
        }
    }

    DFS(1);

    print();

    return 0;
}

C++: /* 
 * ALDS1_11B.cpp
 */
#include <iostream>
#include <vector>
#include <cstdio>
#include <cstdlib>
#include <cstring>

using namespace std;

int N;
int ad_k[101];
int ad_list[101][101];

int jikan = 0;
int d[101], f[101];
bool visited[101];

void visit(int id) {
    if (visited[id])
        return;

    visited[id] = true;
    d[id] = ++jikan;
    for (int i = 0; i < ad_k[id]; ++i) {
        visit(ad_list[id][i]);
    }
    f[id] = ++jikan;
}

int main(void) {

    scanf("%d", &N);
    for (int i = 1, id; i <= N; ++i) {
        scanf("%d", &id);
        scanf("%d", ad_k + id);
        for (int j = 0; j < ad_k[id]; ++j) {
            scanf("%d", ad_list[id] + j);
        }
    }

    for (int i = 1; i <= N; ++i) {
        visit(i);
    }

    for (int i = 1; i <= N; ++i) {
        printf("%d %d %d\n", i, d[i], f[i]);
    }

    return 0;
}

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

using namespace std;
typedef pair<long long int, long long int> PP;

long long int INF = 1e18;
long long int MOD = 1e9 + 7;

vector<int> E[200];
int d[200] = {}, f[200] = {};

int func(int pos, int time){
  if(d[pos] > 0){
    return time;
  }
  d[pos] = time;
  time += 1;
  for(int to : E[pos]){
    time = func(to, time);
  }
  f[pos] = time;
  time += 1;
  return time;
}

int main(){
  int n;
  cin >> n;
  for(int loop = 0; loop < n; loop++){
    int u, k;
    cin >> u >> k;
    for(int i = 0; i < k; i++){
      int v;
      cin >> v;
      E[u].push_back(v);
    }
  }
  int time = 1;
  for(int i = 1; i <= n; i++){
    if(d[i] == 0){
      time = func(i, time);
    }
    cout << i << " " << d[i] << " " << f[i] << endl;
  }
  return 0;
}

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

using namespace std;

struct Edge
{
	int to;
};

vector<vector<int>> DFS(vector<vector<Edge>>& G)
{
	int timecounter = 0;
	int next = 1;
	vector<vector<int>> result;
	result = vector<vector<int>>(2, vector<int>(G.size(), 0));
	vector<int> prev(G.size(),0);
	
	while(result[1][0] == 0){
		int tmp;
		if(result[0][next - 1] == 0){
			timecounter += 1;	
			result[0][next - 1] = timecounter;
		}

		if(G[next - 1].empty()){
			if(result[1][next - 1] == 0){
				timecounter +=1;
				result[1][next - 1] = timecounter;
			}
			next = prev[next - 1];
		}else{
			tmp = G[next - 1].begin()->to;
			G[next - 1].erase(G[next - 1].begin());
			prev[tmp - 1] = next;
			next = tmp;
		}
	}
	return result;
}

int main(void)
{
	int n;
	cin >> n;

	vector<vector<Edge>> AdjList(n);
	for(int i = 0; i < n; i++){
		int u, k;
		cin >> u >> k;
		for(int j = 0; j < k; j++){
			int v;
			cin >> v;
			AdjList[i].push_back(Edge{v});
		}
	}

	vector<vector<int>> timestump = DFS(AdjList);
	
	for(int i = 0; i < AdjList.size(); i++){
		cout << i + 1 << " " << timestump[0][i] << " " << timestump[1][i] << endl;
	}
	return 0;
}

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

#define MAX 101

using namespace std;

int visited[MAX],d[MAX],f[MAX];
int tt=0;
vector<int> G[MAX];

void dfs(int u){
  d[u]=++tt;
  for(int i=0;i<G[u].size();i++){
    if(visited[G[u][i]]==0) dfs(G[u][i]);
  }
  visited[u]=1;
  f[u]=++tt;
}

int main(){
  int n; cin >> n;
  for(int i=1;i<=n;i++) visited[i]=0;
  for(int i=0;i<n;i++){
    int u,k; cin >> u >> k;
    for(int i=0;i<k;i++){
      int v; cin >> v;
      G[u].push_back(v);
    }
  }
  dfs(1);
  for(int i=1;i<=n;i++){
    cout << i << " " << d[i] << " " << f[i] << endl;
  }
}

C++: #include <bits/stdc++.h>
#define REP0(i,n) for(int i=0;i<n;i++)
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2
using namespace std;
int n,M[N][N];
int color[N],D[N],F[N],tt;
int nt[N];
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){
  REP0(i,n) 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();
      }
    } else{
      S.pop();
      color[u]=BLACK;
      F[u]=++tt;
    }
  }
}
void DFS(){
  REP0(i,n){
    color[i]=WHITE;
    nt[i]=0;
  }
  tt=0;
  REP0(u,n) if(color[u]==WHITE) DFS_visit(u);
  REP0(i,n) printf("%d %d %d\n",i+1,D[i],F[i]);
}
int main(){
  int u,k,v;
  scanf("%d",&n);
  REP0(i,n){
    REP0(j,n) M[i][j]=0;
  }
  REP0(i,n){
    scanf("%d %d",&u,&k);
    REP(j,k){
      scanf("%d",&v);
      M[--u][--v]=1;
    }
  }
  DFS();
  return 0;
}