Go: package main

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

const MAX = 101

var f [MAX]int
var d [MAX]int
var list [][]int
var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func dfs(u, cnt int) int {
	if d[u] != 0 {
		return cnt
	}

	cnt++
	d[u] = cnt
	for _, next := range list[u] {
		cnt = dfs(next, cnt)
	}
	cnt++
	f[u] = cnt
	return cnt
}

func main() {
	n := scanInt()
	list = make([][]int, n+1)
	for i := 1; i <= n; i++ {
		u := scanInt()
		k := scanInt()
		for j := 0; j < k; j++ {
			n := scanInt()
			list[u] = append(list[u], n)
		}
	}

	cnt := 0
	for i := 1; i <= n; i++ {
		cnt = dfs(i, cnt)
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 1; i <= n; i++ {
		fmt.Fprint(w, i)
		fmt.Fprint(w, " ")
		fmt.Fprint(w, d[i])
		fmt.Fprint(w, " ")
		fmt.Fprint(w, f[i])
		fmt.Fprintln(w)
	}
	w.Flush()
}

C++: #include<cstdio>
#include<vector>
#include<algorithm>
#include<utility>
#include<numeric>
#include<iostream>
#include<array>
#include<string>
#include<sstream>
#include<stack>
#include<queue>
#include<list>
#define _USE_MATH_DEFINES

#include<math.h>
#include<map>

#define SENTINEL 1000000001

#define min(a,b) (a)>(b)?(b):(a)
#define max(a,b) (a)>(b)?(a):(b)

using namespace std;

int G[101][101];
int d[101];
int f[101];
bool checked[101];

void explore(int id, int n,int& t)
{
	if (checked[id])
	{
		return;
	}
	checked[id] = true;
	d[id] = t;
	t++;

	for (int i = 1; i <= n; i++)
	{
		if (G[id][i] == 1)
		{
			explore(i, n,t);
		}
	}

	f[id] = t;
	t++;
}

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

	for (int i = 0; i < n; i++)
	{
		int id, k;
		cin >> id >> k;

		for (int i = 0; i < k; i++)
		{
			int v;
			cin >> v;
			G[id][v] = 1;
		}
	}

	int t = 1;
	explore(1, n, t);

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

	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
int visit[111],d[111],f[111],t;
//    訪問状態 　　発見　　　完了
int n,M[111][111];
static const int WHITE=0; //未訪問
static const int GRAY=1; //訪問はした
void dfs(int u){
  visit[u]=GRAY; //訪問はした
  d[u]=++t; //発見した時刻
  for(int v=0;v<n;v++){
    if(M[u][v]==0) continue; //辺がない
    if(visit[v]==WHITE) dfs(v);
  }
  f[u]=++t; //訪問完了時刻
}
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); //訪問してないか... iを始点に
  }
  for(int i=0;i<n;i++){
    cout<<i+1<<' '<<d[i]<<' '<<f[i]<<endl;
  }
  return(0);
}

C++: #include <bits/stdc++.h>
#define rep(i, start, end) for (long long i = start; i < end; ++i)
#define srt(x) sort((x).begin(), (x).end());
#define rsrt(x) sort((x).rbegin(), (x).rend());
#define deb(x) cout<<#x<<" = "<<(x)<<" (L"<<LINE<<")"<<endl;
#define vdeb(x) {cout<<#x<<" = { "; rep(i, x.size()) cout<<x[i]<<' '; cout <<'}'<<" (L"<<LINE<<")"<<endl;}
using namespace std;
using ll = long long;
using ld = long double;
using vi = vector<int>;
using vivi = vector<vi>;
using vll = vector<long long>;
using vllvll = vector<vll>;
using vs = vector<string>;
using um = unordered_map<long long, long long>;
const long long INF = 1LL << 60;
const long long MOD = 1e9 + 7;
const long long MAX = 1000;

ll n;
vllvll M(MAX,vll(0));
vll ts1(MAX);
vll ts2(MAX);
vll seen(MAX, 0);

void rec(ll node, ll& ptr)
{
    ts1[node] = ptr++;
    seen[node] = 1;
    for (ll adj : M[node]) {
        if (seen[adj] == 1) continue;
        rec(adj, ptr);
    }
    ts2[node] = ptr++;
}

void dfs()
{
    ll ptr = 1;
    rep(i, 0, n) {
        if (seen[i] == 0) {
            rec(i, ptr);
        }
    }
}

int main()
{
    cin >> n;
    ll u, k, v;
    rep(i, 0, n) {
        cin >> u >> k;
        --u;
        rep(j, 0, k) {
            cin >> v;
            --v;
            M[u].push_back(v);
        }
    }
    ll f = 0, l = 0;
    dfs();
    rep(i, 0, n) {
        cout << i+1 << ' ' << ts1[i] << ' ' << ts2[i]<< endl;
    }
}

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

map<int, vector<int>> A;
int color[101];
int start[101];
int endTime[101];
int elapsed = 0;

void dfs(int u) {
    elapsed++;
    color[u] = 1;
    start[u] = elapsed;
    for (vector<int>::iterator it = A[u].begin(); it != A[u].end(); it++) {
        if (color[*it] == 0) {
            dfs(*it);
        }
    }
    endTime[u] = ++elapsed;
}

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

    int u, k;
    for (int i = 1; i <= n; i++) {
        color[i] = 0;
        cin >> u >> k;
        int ad;
        for (int j = 0; j < k; j++) {
            cin >> ad;
            A[u].push_back(ad);
        }
    }

    for (int i = 1; i <= n; i++) {
        if (color[i] == 0) dfs(i);
    }

    for (int i = 1; i <= n; i++) {
        cout << i << " " << start[i] << " " << endTime[i] << endl;
    }
}

C++: #include <bits/stdc++.h>
using namespace std;
#define r(i,n) for(auto i=0;i<n;i++)
#define s(c) static_cast<int>((c).size())

struct Timestamp{
	int discovered;
	int finished;
};

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

	set<int> A[n+1];
	bool reached[n+1]{};
	int v1, v2, deg;
	r(i, n){
		cin >> v1 >> deg;

		r(j, deg){
			cin >> v2;
			A[v1].insert(v2);
			//A[v2].insert(v1);
		}
	}

	Timestamp ts[n+1];
	for(int i = 1; i <= n; i++){
		ts[i].discovered = 0;
		ts[i].finished = 0;
	}
	ts[1].discovered = 1;


	int time = 0;
	stack<int> s;

	while(true){
		for (int i = 1; i <= n; i++) {
			if (reached[i])
				continue;
			reached[i] = true;
			s.push(i);
			time++;
			ts[i].discovered = time;
			goto DFS;
		}
		break;

		DFS:;
		while (!s.empty()) {
			v1 = s.top();

			bool hasNext = false;
			for (int v2 : A[v1]) {
				if (!reached[v2]) {
					reached[v2] = true;
					s.push(v2);
					hasNext = true;
					break;
				}
			}

			if (!ts[v1].discovered) {
				time++;
				ts[v1].discovered = time;
			}

			if (!hasNext) {
				time++;
				ts[v1].finished = time;
				s.pop();
			}
		}
	}

	for(int i = 1; i <= n; i++){
		printf("%d %d %d\n", i, ts[i].discovered, ts[i].finished);
	}

	return 0;
}

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

std::vector<pair<int, int> > stamp(101);
std::vector<std::vector<int> > v(101);
bool isCheckd[101];
int cnt = 0;

void dfs(int k){
	cnt++;
	isCheckd[k] = true;
	stamp[k].first = cnt;
	for(int i=0;i<v[k].size();i++){
		int next = v[k][i];
		if(!isCheckd[next]){
			dfs(next);
		}
	}
	cnt++;
	stamp[k].second = cnt;
}

int main(){
	int n;

	fill(isCheckd,isCheckd+101,false);
	isCheckd[0] = true;
	cin >> n;

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

	for(int i=0;i<n;i++){
		if(!isCheckd[i])
			dfs(i);
	}


	for(int i=0;i<n;i++){
		cout << i+1 <<" "<< stamp[i+1].first <<" " <<stamp[i+1].second<< endl;
	}

	return 0;
}

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 u,v,k,i,j;
	
	scanf("%d",&n);
	for(i=0;i<n;i++){
		for(j=0;j<n;j++){
			M[i][j]=0;
		}
	}
	
	for(i=0;i<n;i++){
		scanf("%d%d",&u,&k);
		u--;
		for(j=0;j<k;j++){
			scanf("%d",&v);
			v--;
			M[u][v]=1;
		}
	}
	
	dfs();
	
	return 0;
}