Go: package main

/*
深さ優先探索
*/

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

func main() {
	scanner := makeScanner(8192)
	n := eGetInt(scanner)
	g := make([][]int, n+1)
	for i := 1; i < n+1; i++ {
		ints := eGetInts(scanner)
		num, vcount := ints[0], ints[1]
		g[i] = make([]int, vcount)
		for j := 0; j < vcount; j++ {
			g[num][j] = ints[j+2]
		}
	}
	hist := make([]struct{ d, f int }, n+1)
	t := 0
	var visit func(int)
	visit = func(num int) {
		if hist[num].d == 0 {
			stack := []int{}
			t++
			hist[num].d = t
			stack = append(stack, num)
			for len(stack) > 0 {
				// トップを訪問する
				top := stack[len(stack)-1]
				for i := 0; i < len(g[top]); i++ {
					if hist[g[top][i]].d == 0 {
						t++
						hist[g[top][i]].d = t
						stack = append(stack, g[top][i])
						goto endloop
					}
				}
				// 訪問場所がなくなったら
				// pop
				stack = stack[0 : len(stack)-1]
				t++
				hist[top].f = t
			endloop:
			}
		}
	}
	for i := 1; i < n+1; i++ {
		visit(i)
	}
	for i := 1; i < n+1; i++ {
		fmt.Println(i, hist[i].d, hist[i].f)
	}
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetInt64(r *bufio.Scanner) int64 {
	line := eGetLine(r)
	return eAtoInt64(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetInt64s(r *bufio.Scanner) []int64 {
	fields := eGetFields(r)
	ints := make([]int64, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoInt64(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}
func eAtoInt64(s string) int64 {
	n, err := strconv.ParseInt(s, 10, 64)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

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;
}