Go: package main

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

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Scan()
	num, _ := strconv.Atoi(sc.Text())
	nodes := make(map[int]*node)

	for i := 0; i < num; i++ {
		sc.Scan()
		id, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		nodeNum, _ := strconv.Atoi(sc.Text())
		n := node{id, make([]int, 0), 0, 0}
		for j := 0; j < nodeNum; j++ {
			sc.Scan()
			nid, _ := strconv.Atoi(sc.Text())
			n.nexts = append(n.nexts, nid)
		}
		nodes[id] = &n
	}

	s := Stack{}
	for i := 1; i < len(nodes)+1; i++ {
		if nodes[i].s != 0 {
			continue
		}
		walk(i, &nodes, s)
	}
	for i := 1; i < len(nodes)+1; i++ {
		fmt.Printf("%v %v %v\n", (*nodes[i]).id, (*nodes[i]).s, (*nodes[i]).e)
	}
}

var time int

func walk(nid int, nodes *map[int]*node, s Stack) {
	n := (*nodes)[nid]
	if n.s != 0 {
		return
	}
	time++
	n.s = time
	s.Push(n)
	for _, v := range n.nexts {
		walk(v, nodes, s)
	}
	time++
	n.e = time
}

type node struct {
	id    int
	nexts []int
	s     int
	e     int
}

// Stack is Stack
type Stack struct {
	stack []interface{}
}

// Push new value
func (stack *Stack) Push(val interface{}) {
	stack.stack = append(stack.stack, val)
}

// Pop new value
func (stack *Stack) Pop() interface{} {
	val := stack.stack[len(stack.stack)-1]
	stack.stack = stack.stack[0 : len(stack.stack)-1]
	return val
}

C++: #include<iostream>
#include<algorithm>

using namespace std;

int cnt = 0;
int discoverd[100] = { 0 };
int finished[100] = { 0 };
int n = 0;

void dfs(int index, int** mat);

int main() {
	int row,size,tmp;
	cin >> n;
	int** mat = new int* [n];
	for (int i = 0;i < n;i++) {
		cin >> row >> size;
		mat[row - 1] = new int[n];
		for (int j = 0;j < n;j++) {
			mat[row - 1][j] = 0;
		}
		for (int j = 0;j < size;j++) {
			cin >> tmp;
			mat[row - 1][tmp - 1] = 1;
		}
	}
	for (int i = 0;i < n;i++) {
		if (discoverd[i] == 0)dfs(i, mat);
	}
	for (int i = 0;i < n;i++) {
		cout << i + 1 << " " << discoverd[i] << " " << finished[i] << endl;
	}
	
}

void dfs(int index, int** mat) {
	cnt++;
	discoverd[index] = cnt;
	for (int i = 0;i < n;i++) {
		if (mat[index][i] == 1 && discoverd[i] == 0) {
			dfs(i, mat);
		}
	}
	cnt++;
	finished[index] = cnt;
}

C++: #include <cstdio>
#include <iostream>
#include <algorithm>
#include <cmath>
#include <cstring>
using namespace std;

const int maxn = 100 + 5;
int a[maxn][maxn];
bool vis[maxn];
int d[maxn];
int f[maxn];
int time = 0;
int n;

void dfs(int u)
{
    vis[u] = true;
    d[u] = ++time;
    for (int i = 1; i <= n; i++)
        if (a[u][i] && !vis[i])
            dfs(i);
    f[u] = ++time;
}

int main()
{
    while (scanf("%d", &n) != EOF)
    {
        time = 0;
        memset(a, 0, sizeof(a));
        memset(vis, false, sizeof(vis));

        int u, k, x;
        for (int i = 0; i < n; i++)
        {
            scanf("%d %d", &u, &k);
            for (int j = 0; j < k; j++)
            {
                scanf("%d", &x);
                a[u][x] = 1;
            }
        }

        dfs(1);
        for (int i = 1; i <= n; i++)
            printf("%d %d %d\n", i, d[i], f[i]);
    }
    return 0;
}

C++: #include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <cmath>
#include <cstdlib>
using namespace std;

const int MAX = 110;
vector<int> G[MAX];
int dtime[MAX];
int ftime[MAX];
int n;
int tim;

void dfs(int p) {
    if (ftime[p] == -1) dtime[p] = ++tim;
    else return;
    for (int i = 0; i < G[p].size(); i++) {
        dfs(G[p][i]);
    }
    if (ftime[p] == -1) ftime[p] = ++tim;
}

int main() {
    //freopen("in.txt", "r", stdin);
    //freopen("out.txt", "w", stdout);
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) {G[i].clear(); dtime[i]=-1; ftime[i]=-1;}
    tim = 0;
    for (int i = 1; i <= n; i++) {
        int p, k;
        scanf("%d %d", &p, &k);
        while (k--) {
            int ne = 0;
            scanf("%d", &ne);
            G[p].push_back(ne);
        }
        sort(G[p].begin(), G[p].end());
    }
    for (int i = 1; i <= n; i++) {
        dfs(i);
    }
    for (int i = 1; i <= n; i++) {
        printf("%d %d %d\n", i, dtime[i], ftime[i]);
    }
    return 0;
}

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

int n;
int t; //mytime?????????????????§???????´?
int mytime1[110],mytime2[110]; //?????§??????
int mat[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(mat[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<100;i++){
	}
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			mat[i][j]=0;
		}
	}
	for(int i=1;i<n+1;i++){
		for(int j=0;j<v[i].size();j++){
			mat[i-1][v[i][j]-1]=1; //
		}
	}
	for(int i=0;i<n;i++){
    if(c[i]!=1){
      dfs(i);
    }
  }
  for(int i=0;i<n;i++)
    {
      cout<<(i+1)<<' '<<mytime1[i]<<' '<<mytime2[i]<<endl;
    }
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define mod 1000000007
#define MAX 105
#define BLACK 0
#define GRAY 1
#define WHITE 2

int n;
int G[MAX][MAX];
int d[MAX], f[MAX], color[MAX];
int t;

void init();
void dfs();
void dfs_s(int s);

int main(){
    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;
            G[u-1][v-1] = 1;
        }
    }

    dfs();

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

void init(){
    t = 1;
    for(int i = 0; i < n; i++){
        d[i] = f[i] = 0;
        color[i] = WHITE;
        for(int j = 0; j < n; j++){
            G[i][j] = 0;
        }
    }
}

void dfs(){
    for(int i = 0; i < n; i++){
        if(color[i] == WHITE){
            dfs_s(i);
            t++;
        }
    }
}

void dfs_s(int s){
    stack<int> S;
    S.push(s); color[s] = GRAY; d[s] = t;
    int now;

    while(!S.empty()){
        now = S.top();
        t++;
        bool fl = true;

        for(int i = 0; i < n; i++){
            if(G[now][i] == 1 && color[i] == WHITE){
                S.push(i); color[i] = GRAY; d[i] = t;
                now = i; fl = false; break;
            }
        }

        if(fl){
            int top = S.top(); S.pop();
            color[top] = BLACK; f[top] = t;
            now = top;
        }
    }
}