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++: // clang-format off
#include <bits/stdc++.h>
#define int long long
#define main signed main()
// #define main int main()
#define loop(i, a, n) for (int i = (a); i < (n); i++)
#define rep(i, n) loop(i, 0, n)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define prec(n) fixed << setprecision(n)
#define stlice(from, to) substr(from, (to) - (from) + 1)
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define fi first
#define se second
using namespace std;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<double> vd;
typedef vector<char> vc;
typedef vector<bool> vb;
typedef vector<string> vs;
typedef vector<pii> vpii;
typedef vector<vi> vvi;
typedef vector<vb> vvb;
typedef vector<vpii> vvpii;
const int INF = sizeof(int) == sizeof(long long) ? 1000000000000000000LL : 1000000000;
const int MOD = 1000000007;
const double PI = acos(-1);
template<typename A, typename B> bool cmin(A &a, const B &b) { return a > b ? (a = b, true) : false; }
template<typename A, typename B> bool cmax(A &a, const B &b) { return a < b ? (a = b, true) : false; }
bool odd(const int &n) { return n & 1; }
bool even(const int &n) { return !odd(n); }
void solve();
main { solve(); return 0; }
// clang-format on

typedef int Weight;

struct Edge {
  int src, dst;
  Weight weight;
  Edge(int s, int d, Weight w)
    : src(s), dst(d), weight(w) {
  }
};

typedef vector<Edge> Edges;
typedef vector<Edges> Graph;
typedef vector<Weight> Array;
typedef vector<Array> Matrix;

void addEdge(Graph &g, int a, int b, Weight w = 1) {
  g[a].emplace_back(a, b, w);
  g[b].emplace_back(b, a, w);
}

void addArc(Graph &g, int a, int b, Weight w = 1) {
  g[a].emplace_back(a, b, w);
}

void solve() {
  int n;
  cin >> n;
  Graph g(n);
  rep(i, n) {
    int u, k;
    cin >> u >> k;
    u--;
    while (k--) {
      int v;
      cin >> v;
      v--;
      addArc(g, u, v);
    }
  }
  int c = 1;
  vi done(n);
  vpii time(n);
  function<void(int)> dfs = [&](int x) {
    if (done[x]) return;
    done[x]    = true;
    time[x].fi = c++;
    for (Edge e : g[x]) {
      dfs(e.dst);
    }
    time[x].se = c++;
  };
  rep(i, n) dfs(i);
  rep(i, n) {
    cout << i + 1 << ' ' << time[i].fi << ' ' << time[i].se << endl;
  }
}

C++: 
#include<iostream>
#include<stack>
using namespace std;
#define NIL -999
bool mark[105][105];
int n;
int tm = 0;
int d[105] = { 0 };
int f[105] = { 0 };

inline int next(int i) {
	for (int tmp = 1; tmp <= n; ++tmp) {
		if (mark[i][tmp] && !d[tmp]) {
			//cout << endl << i << "的下一个节点是：" << tmp << endl;
			return tmp;
		}
	}
	//cout << endl << i << "的下一个节点是：" << NIL << endl;
	return NIL;
}

void dfs_IN(int i) {
	stack<int> s;
	int now = i, nt;
	d[i] = ++tm;
	s.push(i);
	//	s.push(i);
	//	d[i] = ++tm;
	//first solution
	/*do {
		//		cout<<"visit: "<<now<<endl;
		if (!s.empty()) {
			now = s.top();
			s.pop();
		}
		do {
			//cout << "visit: " << now << endl;
			nt = next(now);
			if (nt != NIL && !d[nt]) {
				s.push(now);
				d[nt] = ++tm;
				now = nt;
			}
			else break;
		} while (true);
		//cout << "end visit:  " << now << endl;
		f[now] = ++tm;
		
	} while (!s.empty());*/
	//solution 2
	while (!s.empty()) {
		now = s.top();
		nt = next(now);
		if (nt != NIL) {
			d[nt] = ++tm;
			s.push(nt);
		}
		else {
			s.pop();
			f[now] = ++tm;
		}
	}
}

void dfs() {
	for (int i = 0; i <= n + 2; ++i)
		for (int k = 1; k <= n + 2; ++k)
			mark[i][k] = false;

	int Node, k, tmp;
	cin >> n;
	for (int l = 0; l<n; l++) {
		cin >> Node >> k;
		for (int x = 0; x<k; x++) {
			cin >> tmp;
			mark[Node][tmp] = true;
		}
	}

	for (int p = 1; p <= n; ++p)
		if(!d[p])dfs_IN(p);

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

}

int main() {

	dfs();
	return 0;
}

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

#define NIL 0

struct Node{
    int d=0, f=0, ch=0;
    int child[100]={0};
};

Node nodes[101];

int search(int num, int time){
    if(nodes[num].d!=NIL){
        return time;
    }
    nodes[num].d = time;
    ++time;
    for(int i=0;i<nodes[num].ch;++i){
        time = search(nodes[num].child[i], time);
    }
    nodes[num].f = time;
    ++time;
    return time;
}

int main(){
    
    int n, num=0, time = 1;
    cin >> n;
    for(int i=1;i<=n;++i){
        cin>>num;
        cin >> nodes[num].ch;
        for(int j=0;j<nodes[num].ch;++j){
            cin >> nodes[num].child[j];
        }
    }
    
    
    for(int i=1;i<=n;++i){
        if(nodes[i].d==NIL){
            time = search(i, time);
        }
    }
    
    
    for(int i=1;i<=n;i++){
        cout << i << " " << nodes[i].d << " " <<nodes[i].f << endl;
        
    }
    
    
    
    return 0;
}

C++: #include<iostream>
using namespace std;
typedef struct{
  int A[1000];
  int begin;
  int end;
}node;
node T[105];
int times=0;
  int n;
void function(int num){
  if(T[num].begin==0){
  times++;
    T[num].begin=times;
  }
  for(int j=1;j<=n;j++){
    if(T[num].A[j]==1){
      T[num].A[j]=0;
      function(j);
    }
  }
  if(T[num].end==0){
    times++;
    T[num].end=times;
  }
}
int main(){
  int num;
  int son;
  int z;
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>num;
    cin>>son;
    for(int j=0;j<son;j++){
      cin>>z;
      T[num].A[z]=1;
      }
  }
  for(int i=1;i<=n;i++){
    function(i);
  }
  for(int i=1;i<=n;i++){
      cout<<i<<" "<<T[i].begin<<" "<<T[i].end<<endl;
  }


  return 0;
}

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

vector<int> d, f;
int g[111][111];
int n;
int cnt;

void dfs(int now){
  bool flag = false;
  if(d[now] != 0) flag = true;
  else{
    cnt++;
    d[now] = cnt;
  }
  for(int i = 1; i <= n; i++){
    if(g[now-1][i-1] == 1 && d[i] == 0){
      dfs(i);
    }
  }
  cnt++;
  if(flag) cnt--;
  if(f[now] == 0) f[now] = cnt;
}

int main(){

  memset(g,0,sizeof(g));
  d.resize(111);
  f.resize(111);
  cin >> n;

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

  for(int i = 0; i < n; i++){
    dfs(i+1);
  }

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





}

C++: #include<stdio.h>
#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()
{
    int a,b,c;
    scanf("%d",&n);
    for(int i=0;i<n;i++)
    {
        scanf("%d %d",&a,&b);
        a--;
        for(int i=0;i<b;i++)
        {
            scanf("%d",&c);
            c--;
            M[a][c]++;
        }
    }
    dfs();
    return 0;
}