Go: package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
)

const N = 100

const (
	WHITE = iota
	GRAY
	BLACK
)

type Graph struct {
	M               [N][N]int
	color, d, f, nt [N]int
	tt              int
}

func (g *Graph) next(u, n int) int {
	for v := g.nt[u]; v < n; v++ {
		g.nt[u] = v + 1
		if g.M[u][v] != 0 {
			return v
		}
	}
	return -1
}

func (g *Graph) dfsVisit(r, n int) {
	var S []int
	S = append([]int{r}, S...)
	g.color[r] = GRAY
	g.tt++
	g.d[r] = g.tt

	for len(S) != 0 {
		u := S[0]
		v := g.next(u, n)
		if v == -1 {
			S = S[1:]
			g.color[u] = BLACK
			g.tt++
			g.f[u] = g.tt
			continue
		}

		if g.color[v] != WHITE {
			continue
		}

		g.color[v] = GRAY
		g.tt++
		g.d[v] = g.tt
		S = append([]int{v}, S...)
	}
}

func (g *Graph) dfs(n int) string {
	for i := 0; i < n; i++ {
		g.color[i] = WHITE
	}
	g.tt = 0

	for u := 0; u < n; u++ {
		if g.color[u] == WHITE {
			g.dfsVisit(u, n)
		}
	}

	var out bytes.Buffer
	for i := 0; i < n; i++ {
		out.WriteString(fmt.Sprintf("%d %d %d\n", i+1, g.d[i], g.f[i]))
	}

	return strings.TrimRight(out.String(), "\n")
}

func answer(reader io.Reader) string {
	sc := bufio.NewScanner(reader)
	sc.Split(bufio.ScanWords)

	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())

	var g Graph
	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())
		u--
		for j := 0; j < k; j++ {
			sc.Scan()
			v, _ := strconv.Atoi(sc.Text())
			v--
			g.M[u][v] = 1
		}
	}

	return g.dfs(n)
}

func main() {
	fmt.Println(answer(os.Stdin))
}

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;
    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 <bits/stdc++.h>
using namespace std;

void dfs(int& time,
    int start,
    const vector<vector<int>>& graph,
    vector<int>& arraialTimes,
    vector<int>& leftTimes,
    vector<bool>& checkList)
{
    stack<int> stack;
    stack.push(start);
    checkList[start] = true;
    arraialTimes[start] = ++time;
 
    while (!stack.empty())
    {
        int v = stack.top();
        int vSize = 0;
        for (int w : graph[v]) {
            if (!checkList[w]) {
                ++vSize;
                stack.push(w);
                checkList[w] = true;
                arraialTimes[w] = ++time;
                break;
            }
        }
        if (vSize == 0) {
            stack.pop();
            leftTimes[v] = ++time;
        }
    }
}

int main() {
    int n;
    cin >> n;
    vector<vector<int>> graph(n);
    vector<bool> checkList(n);
    vector<int> arrivalTimes(n);
    vector<int> leftTimes(n);


    graph.reserve(n);
    for (auto& g : graph) {
        int id;
        cin >> id;
        int size;
        cin >> size;
        for (int j = 0; j < size; ++j) {
            int k;
            cin >> k;
            g.push_back(k-1);
        }
    }
    int time = 0;
    for (int i = 0; i < n; ++i) {
        if (!checkList[i]) {
            dfs(time, i, graph, arrivalTimes, leftTimes, checkList);
        }
    }
    for (int i = 0; i < n; ++i) {
        cout << i+ 1 << " " << arrivalTimes[i] << " " << leftTimes[i]<< endl;
    }

}

C++: #include <iostream>
#include <cstdio>
#include <cstring>
#include <stack>
using namespace std;
const int maxx = 110;
int n, m[maxx][maxx];
int u, num, v;
int d[maxx], f[maxx];
int flag[maxx];
int nowtime = 1;

void dfs(int u) {

    // 入栈时间
    flag[u] = 1;
    d[u] = nowtime++;
    for (int i = 1; i <= n; i++) {
        if (flag[i] == 0 && m[u][i] == 1) {
            dfs(i);
        }
    }
    //出栈时间
    f[u] = nowtime++;
}

int main()
{

    scanf("%d", &n);
    memset(m, 0, sizeof(m));
    memset(f, 0, sizeof(f));
    for (int i = 1; i <= n; i++) {
        scanf("%d %d", &u, &num);
        for (int j = 1; j <= num; j++) {
            scanf("%d", &v);
            m[u][v] = 1;
        }
    }
    for (int i = 1; i <= n; i++) {
        if(flag[i] == 0)
            dfs(i);
    }
    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 n,lis[111][111]={},d[111]={},f[111],t=1;

void dfs(int now){
  d[now]=t++;
  for(int i=1;i<=n;i++)
    if(lis[now][i]&&d[i]==0)dfs(i);
  f[now]=t++;
}

int main(){
  cin>>n;
  for(int c=0;c<n;c++){
    int u,k,v;
    cin>>u>>k;
    for(int i=0;i<k;i++){
      cin>>v;
      lis[u][v]=1;
    }
  }
  for(int i=1;i<=n;i++)if(d[i]==0)dfs(i);
  for(int i=1;i<=n;i++)cout<<i<<" "<<d[i]<<" "<<f[i]<<endl;  
  
  return 0;
}

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

struct node {
	int num;
	std::vector<int> child;
};

int recurcive(node nodes[],int d[100], int f[100], int n, int count) {
	d[n] = count++;
	for (size_t i = 0; i < nodes[n].child.size(); i++) {
		if (d[nodes[n].child[i]] == 0) {
			count = recurcive(nodes, d, f, nodes[n].child[i], count);
		} else {
			nodes[n].child.erase(std::find(nodes[n].child.begin(), nodes[n].child.end(), nodes[n].child[i]));
		}
	}
	f[n] = count++;

	return count;
}

int main() {
	int node_num;
	node nodes[100];
	std::cin >> node_num;

	for (int i = 0; i < node_num; i++) {
		int n, num;
		std::cin >> n >> num;
		for (int j = 0; j < num; j++) {
			int val;
			std::cin >> val;
			nodes[n - 1].child.push_back(val - 1);
		}
	}

	std::stack<int> st, st2;
	std::vector<int> gone;
	int d[100], f[100];
	int count = 1;

	for (int i = 0; i < 100; i++)
		d[i] = 0;

	recurcive(nodes, d, f, 0, 1);

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

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

int d[110],f[110];
bool visited[110];
int timestamp = 1;

int n; vector<vector<int>> to;

void dfs(int u){
  if( visited[u] ){ return ;}
  visited[u] = true;
  d[u] = timestamp;
  timestamp++;
  for(auto ne : to[u]){
    if(visited[ne]){continue;}
    dfs(ne);
  }
  f[u] = timestamp;
  timestamp++;
  
  return ;
}
  

signed main(void){
  cin >> n;
  to.resize(n);
  for(int i = 0; i < n; i++){
    int u,k; cin >> u >> k; u--;
    for(int j = 0; j < k; j++){
      int a; cin >> a; a--;
       to[u].push_back(a);
    }
  }
  
  for(int i = 0; i < n; i++){ 
    sort(to[i].begin(),to[i].end());
  }
  
  for(int i = 0; i < n; i++){ dfs(i);}
  
  for(int i = 0; i < n; i++){ cout << i+1 << " " << d[i] << " "<< f[i] << endl;}
  
  return 0;
}