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 <iostream>
#include <vector>
using namespace std;

int n;
int t; //mytime?????????????????§???????´?
int mytime1[110],mytime2[110]; //?????§??????
int G[110][110];
int c[110];

void dfs(int cur){
	t+=1;
	mytime1[cur]=t;
	c[cur]=1;
	for(int dst=0; dst<n; ++dst){
		if(G[dst][cur]==1&&c[dst]==0){
			dfs(dst);
			t += 1;
		}
	} 
	mytime2[cur]=t;
}


int main()
{
	vector<int> v[110];
	cin>>n;
	for(int i=0;i<n;i++){
		int u,k;
		cin>>u>>k;
		for(int j=0;j<k;j++){
			int tmp;
			cin>>tmp;
			v[u].push_back(tmp);
		}
	}
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			G[i][j]=0;
		}
	}
	for(int i=1;i<n+1;i++){
		for(int j=0;j<v[i].size();j++){
			G[i-1][v[i][j]-1]=1; //
		}
	}
	for(int i=0;i<n;++i){
		dfs(i);
		cout<<(i+1)<<' '<<mytime1[i]<<" "<<mytime2[i] <<endl;
}
}

C++: #include<bits/stdc++.h>
#define N 105
using namespace std;
int n,u,k,v,e[N][N],cnt;
int ans1[N],ans2[N];
bool used[N];

void dfs(int x){
  if(used[x])return;
  used[x]=true;
  ans1[x]=cnt++;
  for(int i=0;i<n;i++)
    if(e[x][i])dfs(i);
  ans2[x]=cnt++;
}

int main(){
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>u>>k;
    for(int j=0;j<k;j++)
      cin>>v,e[u-1][v-1]=1;
  }
  cnt=1;
  for(int i=0;i<n;i++){
    if(!used[i])dfs(i);
  }
  for(int i=0;i<n;i++){
    cout<<i+1<<' '<<ans1[i]<<' '<<ans2[i]<<endl;
  }
  return 0;
}

C++: #include <iostream>
#include <utility>
#define N 	100

using namespace std;

int T[N+1][N+1];
pair<int , int> M[N+1];
int t = 0;

void init(){
	for (int i = 0; i < 100; ++i)
	{
		M[i].first = 0;
		M[i].second = 0;
		for (int j = 0; j < 100; ++j)
		{
			T[i][j] = 0;
		}
	}
}

void DispTable(int n){
	for (int i = 1; i <= n; ++i)
	{
		for (int j = 1; j <= n; ++j)
		{
			cout << T[i][j];
			if(j!=n) cout << " ";
		}
		cout << endl;
	}
}

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

void dfs(int cur,int n){
	t++;
	M[cur].first = t;
	// cerr << "visiting " << cur << " " << t << endl;
	for (int i = 1; i <= n; ++i)
	{
		if(T[cur][i] == 1 && M[i].first == 0) dfs(i,n);
	}
	t++;
	M[cur].second = t;
}

int main(){
	int n;
	cin >> n;
	init();
	for (int i = 0; i < n; ++i)
	{
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; ++j)
		{
			int v;
			cin >> v;
			T[u][v] = 1;	
		}
	}
	// DispTable(n);
	dfs(1,n);
	for (int i = 2; i <= n; ++i)
	{
		if(M[i].first==0) dfs(i,n);
	}
	DispM(n);
	return 0;
}

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


void solve(int);

typedef struct{
  int k;
  vector<int> ls;
  int f,d;
}node_t;

node_t node[101];
int t=0;

int main(){
  int n;
  int u;

  cin >> n;
  for(int i=0; i<n; i++){
    cin >> u; 
    cin >> node[u].k;
    node[u].ls.resize(node[u].k);
    node[u].d = node[u].f = -1;
    for(int j=0; j<node[u].k; j++){
      cin >> node[u].ls[j];
    }
    sort(node[u].ls.begin() , node[u].ls.end());
  }
 
  solve(1);

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

  return 0;
}



void solve(int id){
  t++;
  if(node[id].d == -1)node[id].d = t;
  else {t--;return;}

  for(int i=0; i<node[id].k; i++){
    solve(node[id].ls[i]);
  }
  node[id].f = ++t;
}

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, 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) {
    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 {
            S.pop();
            color[u] = BLACK;
            f[u] = ++tt;
        }
    }
}

void dfs() {
    // ?????????
    for (int i = 0; i < n; ++i) {
        color[i] = WHITE;
        nt[i] = 0;
    }
    tt = 0;

    // ????¨??????? u ????§??????¨????????±???????????¢?´¢
    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 u, k, v;

    cin >> n;
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < n; ++j) {
            M[i][j] = 0;
        }
    }

    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;
        }
    }

    dfs();

    return 0;
}

C++: #include<iostream>
#include<cstdio>
using namespace std;
int arisutoteresu[200][200] = {0};
int imap[200][200] = {0};
int n,u,k[200];
int GetIt[200]={0};
int FinIt[200]={0};
bool used[200] = {false};
int fincou=1;
void dfs(int where,int find){
  fincou++;
 
  GetIt[where]=find;
  if(k[where] != 0){
    for(int i=0;i<k[where];i++){
      if(!used[where]){
	dfs(imap[where][i],find+1);
	fincou++;
	used[where] = true;
      }
    }
  }
    FinIt[where] = fincou;
    
}

int main(){
 
  int ad;
  
  scanf("%d",&n);
  for(int i=0;i<n;i++){
    cin >> u;
    cin >> k[u];
    for(int j=0;j<k[u];j++){
      cin >> ad;
      arisutoteresu[u][ad] = 1;
      imap[u][j] = ad; 
    }
  }


  for(int j=0;j<n;j++)used[j] = false;
  dfs(1,1);

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

  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <cstdio>
#include <vector>
#include <stack>
using namespace std;
#define maxn 105
const int WHITE = 0;
const int GRAY  = 1;
const int BLACK = 2;
int g[maxn][maxn];
int d[maxn],f[maxn];
stack<int> s;
int color[maxn];
int t,n;
void dfs_visit(int u)
{
    color[u]=GRAY;
    d[u]=++t;
    for(int v=1;v<=n;v++)
    {
        if(g[u][v]==0) continue;
        if(color[v]==WHITE)
            dfs_visit(v);
    }
    color[u]=BLACK;
    f[u]=++t;
}
void dfs()
{
    for(int u=1;u<=n;u++)
        color[u]=WHITE;
    for(int u=1;u<=n;u++)
    {
        if(color[u]==WHITE)
            dfs_visit(u);
    }
    for(int u=1;u<=n;u++)
        printf("%d %d %d\n",u,d[u],f[u]);
}
int main()
{
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
    {
        int u,k;
        scanf("%d%d",&u,&k);
        for(int j=1;j<=k;j++)
        {
            int v;
            scanf("%d",&v);
            g[u][v]=1;
        }
    }
    dfs();
    return 0;
}