Go: package main

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

type vertexId int

type vertex struct {
	id vertexId
	firstVisitAt int
	finishVisitAt int
	adjs []vertexId
}

func createVertex(id int, adjsInt []int) vertex {
	adjs := make([]vertexId, len(adjsInt))
	for i := 0; i < len(adjs); i++ {
		adjs[i] = vertexId(adjsInt[i])
	}
	return vertex{
		id: vertexId(id),
		firstVisitAt: 0,
		finishVisitAt: 0,
		adjs: adjs,
	}
}

func (v *vertex) isVisited() bool {
	return v.firstVisitAt > 0
}

func dfs(currentId vertexId, timestamp int, vertices []vertex) int {
	currentVertex := &vertices[currentId-1]
	if currentVertex.isVisited() {
		return timestamp
	}
	timestamp = timestamp + 1
	currentVertex.firstVisitAt = timestamp
	for _, adjId := range currentVertex.adjs {
		timestamp = dfs(adjId, timestamp, vertices)
	}
	timestamp = timestamp + 1
	currentVertex.finishVisitAt = timestamp
	return timestamp
}

func solveDfs(vertices []vertex) {
	timestamp := 0
	for {
		vid := vertexId(-1)
		for i := 0; i < len(vertices); i++ {
			if !vertices[i].isVisited() {
				vid = vertexId(i+1)
				break
			}
		}
		if vid > 0 {
			timestamp = dfs(vid, timestamp, vertices)
		} else {
			break
		}
	}
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	vertices := make([]vertex, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjN, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjs := make([]int, adjN)
		for j := 0; j < adjN; j++ {
			adjId, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			adjs[j] = adjId
		}
		vertices[i] = createVertex(id, adjs)
	}

	solveDfs(vertices)

	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", vertices[i].id, vertices[i].firstVisitAt, vertices[i].finishVisitAt)
	}
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func nextInt(sc *bufio.Scanner) (int, error) {
	return strconv.Atoi(nextText(sc))
}

Python: graph={}
num = int(input())
Adj = [[0 for i in range(num)] for i in range(num)]
for i in range(num):
    l = list(map(int,input().split()))
    graph[str(l[0])]=l[2:]

color = [0] * num
d = [0] * num
f = [0] * num
t = 0
def dfs(u):
    global t
    color[u - 1] = 1
    t += 1
    d[u - 1] = t
    for i in range(1, num+1):
        if Adj[u - 1][i - 1] == 1 and color[i - 1] == 0:
            dfs(i)
    color[u - 1] = 2
    t += 1
    f[u - 1] = t
 
for i in range(1, num+1):
    if color[i-1] == 0:
        dfs(i)
for i in range(num):
    print("{} {} {}".format(i+1,d[i],f[i]))

Python: n = int(input())
G = [[] for _ in range(n)]
u1 = 0
for _ in range(n):
    u, k, *v = [int(i) for i in input().split()]
    G[u - 1] = v
    if k != 0 and u1 == 0:
        u1 = u

time = 1
u = u1
D = []
out = [[i+1, 0, 0] for i in range(n)]
T = []
while True:
    if u not in D:
        out[u - 1][1] = time
        D.append(u)
        T.append(u)

    for d in D:
        if d in G[u - 1]:
            idx = G[u - 1].index(d)
            del G[u - 1][idx]

    if G[u - 1] == []:
        time += 1
        out[T.pop() - 1][2] = time
        if T == []:
            if len(D) == n:
                break
            else:
                for ni in range(n):
                    if ni + 1 not in D:
                        u = ni + 1
                        break
                time += 1
                continue
        else:
            u = T[-1]
    else:
        u = G[u - 1].pop(0)
        time += 1

for ni in range(n):
    print(*out[ni])

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

using namespace std;
int timetime = 0;

void dfs(int cur, vector<vector <int> > &list, vector<int> &d, vector<int> &f) {
		d[cur] =timetime;
		timetime +=1;
    for(int i = cur+1; i < list.size();i++){
      vector<int>::iterator n1end = list[cur].end();
	  vector<int>::iterator n1sres = find(list[cur].begin(),list[cur].end(),i);
      if(d[i] == -1 &&  n1end != n1sres  ){
        dfs(i,list,d,f);
      }
    }
    f[cur] = timetime;
    timetime +=1;
}

int main() {
  int np;
  int k,t,x;
  cin >> np ;
 
  vector <vector <int> > list(np);
  for(int i = 0;i<np;i++) {
    cin >> k;
    cin >> t;
    for(int j = 0; j < t ;j++) {
      cin >>x;
      list[k-1].push_back(x-1);
	  list[x-1].push_back(k-1);
    }
  }
  for(int i = 0 ; i< np;i++){
	sort(list[i].begin(),list[i].end());
  }
  vector <int> d(np,-1);
  vector <int> f(np,0);
  dfs(0,list,d,f);
  for(int i = 0;i < np; i++){
    cout << i+1 <<" "<<d[i]+1 <<" "<<f[i]+1<<endl;
  }


  return 0;
}

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

int num = 1;
bool visited[1000];
vector<int> v[1000], seq[1000];
void dfs(int k){
    seq[k].pb(num++);
    if(visited[k]) return;
    visited[k] = 1;
    for (auto t : v[k]){
        if(visited[t]) continue;
        dfs(t);
    }
    seq[k].pb(num++); return;

}
int main(){
    int n; cin >> n;
    memset(visited, 0, sizeof(visited));
    for (int i = 0; i < n; i++){
        int x, y, z; cin >> x >> y;
        for (int j = 0; j < y; j++){
            cin >> z; v[x].pb(z);
        }
    }
    for(int i = 1; i <= n; i++)
        sort(v[i].begin(), v[i].end());
    for(int i = 1; i <= n; i++)
        if(!visited[i])
            dfs(i);
    for (int i = 1; i <= n; i++){
        cout << i << ' ';
        for (auto k : seq[i])
        cout << k << ' ';
        cout << '\n';
    }
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i = 0, i##_len = (n); i < i##_len; ++i)
#define rep2(i, x, n) for(int i = x, i##_len = (n); i < i##_len; ++i)
#define all(n) begin(n), end(n)
using ll = long long;
using P = pair<int, int>;
using vi = vector<int>;
using vl = vector<ll>;
using vs = vector<string>;
using vc = vector<char>;
using vb = vector<bool>;
using vd = vector<double>;
vi dir = {-1, 0, 1, 0, -1, -1, 1, 1, -1};

int n, t = 0;
vector<set<int>> g;
vi d, f;

void dfs(int v) {
  t++;
  d[v] = t;
  for(auto i : g[v])
    if(d[i] == 0) dfs(i);
  t++;
  f[v] = t;
}

int main() {
  cin >> n;
  d = vi(n, 0);
  f = vi(n, 0);
  g = vector<set<int>>(n);
  rep(i, n) {
    int u, k;
    cin >> u >> k;
    rep(j, k) {
      int v;
      cin >> v;
      v--;
      g[i].insert(v);
    }
  }
  rep(i, n) if(d[i] == 0) dfs(i);
  rep(i, n) printf("%d %d %d\n", i + 1, d[i], f[i]);
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rep2(i, s, n) for (int i = s; i < (int)(n); i++)
#define rep3(i, s, n) for (int i = s; i > (int)(n); i--)
#define all(obj) obj.begin(), obj.end()
#define db(x) cerr << #x << ":" << x << " "
#define dbl(x) cerr << #x << ":" << x << "\n"
#define dbv(vec) cerr << #vec << ":"; for (auto e : vec) cerr << e << " "; cout << "\n"
#define dbvv(vv) cerr << #vv << ":\n"; for (auto vec : vv) { for (auto e : vec) cerr << e << " "; cerr << endl; }
#define YN(f) cout << (f ? "YES" : "NO") << endl
#define Yn(f) cout << (f ? "Yes" : "No") << endl
#define yn(f) cout << (f ? "yes" : "no") << endl
using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using pii = pair<int, int>;

vi d, f;
vector<bool> r;
int t;

void dfs(vvi &g, int u) {	
	r[u] = true;
	d[u] = t++;
	for (int v : g[u]) {
		if (r[v]) continue;
		dfs(g, v);
	}
	f[u] = t++;
}

int main() {
	int n; cin >> n;
	vvi g(n + 1);
	rep(j, n) {
		int u, k; cin >> u >> k;
		rep(j, k) {
			int vj; cin >> vj;
			g[u].push_back(vj);
		}
	}

	r.assign(n + 1, false);
	d.assign(n + 1, 0); f.assign(n + 1, 0);
	t = 1;
	rep2(i, 1, n + 1) if (!r[i]) dfs(g, i);
	/*
	dbvv(g);
	dbv(d);
	dbv(f);
	*/
	rep2(i, 1, n + 1) {
		printf("%d %d %d\n", i, d[i], f[i]);
	}
}