Go: package main

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

var N int
var A [][]int
var t int
var color, d, f []int

const (
	WHITE = iota
	GRAY
	BLACK
)

func dfsVisit(u int) {
	color[u] = GRAY
	t ++
	d[u] = t
	for v:=0; v<N; v++ {
		if A[u][v] == 0 {
			continue
		}
		if color[v] == WHITE {
			dfsVisit(v)
		}
	}
	color[u] = BLACK
	t++
	f[u] = t
}

func dfs() {
	for u:=0; u<N; u++ {
		if color[u] == WHITE {
			dfsVisit(u)
		}
	}
	for u:=0; u<N; u++{
		fmt.Printf("%d %d %d\n", u+1, d[u], f[u])
	}
}


func nextInt(scanner *bufio.Scanner) int {
	scanner.Scan()
	num, _ := strconv.Atoi(scanner.Text())
	return num
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	N = nextInt(scanner)
	color = make([]int, N)
	d = make([]int, N)
	f = make([]int, N)
	A = make([][]int, N)
	for i:=0; i<N; i++{
		A[i] = make([]int, N)
	}
	for i:=0; i<N; i++{
		index := nextInt(scanner) - 1
		cnt := nextInt(scanner)
		for j:=0; j<cnt; j++ {
			v := nextInt(scanner) - 1
			A[index][v] = 1
		}
	}
	dfs()
}

C++: #include<iostream>
using namespace std;
int ans[100][2],degree,count=1;
int arr[100][100],visible[100];
void dfs(int i)
{
	for(int j=0;j<degree;j++)
	{
		if(arr[i][j]==1 && visible[j]==0)
		{			
			ans[j][0]=count++;
			visible[j]=1;
			dfs(j);
			ans[j][1]=count++;
		}
	}
}
int main()
{
	int number,num;
	cin>>degree;

	for(int i=0;i<100;i++)
	{
		visible[i]=0;
	}	
	for(int i=0;i<degree;i++)
	{
		for(int j=0;j<degree;j++)
		{
			arr[i][j]=0;
		}
	}
	for(int i=0;i<degree;i++)
	{
		cin>>number;
		cin>>number;
		for(int j=0;j<number;j++)
		{
			cin>>num;
			arr[i][num-1]=1;
		}
	}
	for(int i=0;i<degree;i++)
	{
		if(visible[i]==0)
		{
			ans[i][0]=count++;
			visible[i]=1;
			dfs(i);
			ans[i][1]=count++;
		}
	}
	for(int i=0;i<degree;i++)
	{
		cout<<i+1<<" "<<ans[i][0]<<" "<<ans[i][1]<<endl;
	}
}

C++: #include <iostream>
using namespace std;
static const int N = 100;
static const int NONE = 0;
static const int DETECTED = 1;
static const int FINISHED = 2;

int M[N][N];

void dfs(int u, int n, int M[N][N], int status[], int t_detected[], int t_finished[], int &t) {
    status[u] = DETECTED;
    t_detected[u] = ++t;
    for (int v = 0; v < n; v++) {
        if (M[u][v] != 0 && status[v] == NONE) {
            dfs(v, n, M, status, t_detected, t_finished, t);
        }
    }
    status[u] = FINISHED;
    t_finished[u] = ++t;
}

int main() {
    int n, 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;
        }
    }

    int status[n], t_detected[n], t_finished[n];
    for (u = 0; u < n; u++) {
        status[u] = NONE;
        // t_detected[u] = 0;
        // t_finished[u] = 0;
    }
    int t = 0;

    for (u = 0; u < n; u++) {
        if (status[u] == NONE) dfs(u, n, M, status, t_detected, t_finished, t);
    }

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

    return 0;
}