Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	f         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []*DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]*DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes] = &DirectedGraphNode{}
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].f = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

var time = 0

func fillDistancesByDepthFirstSearch(g *DirectedGraph) {
	for _, u := range g.nodes[1:] {
		if !u.visited {
			dfsVisit(g, u)
		}
	}
}

func dfsVisit(g *DirectedGraph, u *DirectedGraphNode) {
	time++
	u.d = time

	u.visited = true
	for _, v := range u.adjacents {
		if !v.visited {
			v.parent = u
			dfsVisit(g, v)
		}
	}
	time++
	u.f = time
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	fillDistancesByDepthFirstSearch(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		fmt.Println(node.key, node.d, node.f)
	}
}

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

vector<int> graph[100];
int start[100],endt[100];
int cnt;

void dfs(int num){
	start[num] = ++cnt;
	for(int i = 0;i < graph[num].size();i++){
		if(graph[num][i] != num && !start[graph[num][i]] && !endt[graph[num][i]]) dfs(graph[num][i]);
	}
	endt[num] = ++cnt;
}

int main(){
	int n;
	cin >> n;
	for(int i = 0;i < n;i++){
		int now,m;
		cin >> now >> m;
		for(int j = 0;j < m;j++){
			int t;
			cin >> t;
			graph[now - 1].push_back(t - 1);
		}
	}
	dfs(0);
	for(int i = 0;i < n;i++){
		if(!endt[i]) dfs(i);
	}
	for(int i = 0;i < n;i++){
		cout << i + 1 << " " << start[i] << " " << endt[i] << endl;
	}
	return 0;
}

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

vector<int> d(100), f(100);
vector<vector<int>> G(100);
int cnt = 1;

void dfs(int i) {
    d[i] = cnt++;
    for (auto v : G[i]) {
        if (d[v] == 0) dfs(v);
    }
    f[i] = cnt++;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    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].push_back(v - 1);
        }
    }
    for (int i = 0; i < n; i++) {
        if (d[i] == 0) dfs(i);
    }
    for (int i = 0; i < n; i++) {
        cout << i + 1 << " " << d[i] << " " << f[i] << endl;
    }

    return 0;
}

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<iostream>
#include<vector>
#include<limits.h>
#include<stack>
#include<string>
using namespace std;

struct Vertex{
	int deg;
	vector<int> adj;
	int checked;
	int parent;
};

int out(vector<int> &A){
	int n=A.size();
	int i;
	if (n==0){
		cout << "nothing" <<endl;
	}else if(n==1){
		cout << A[0] << endl;
	}else{
		for (i=0;i<=n-2;i++){
			cout << A[i] << " ";
		}
		cout << A[n-1] <<endl;
	}
}

int Next(vector<Vertex> &L,vector<int> &d, vector<int> &f, int cur, int count){
	int next,i,v;
	if(L[cur].deg==0){
		next=L[cur].parent;
		f[cur]=count;
		return next;
	}
	
	for (i=0;i<L[cur].deg;i++){
		v=L[cur].adj[i];
		if(L[v].checked==0){
			break;
			}
		}
		if(i==L[cur].deg){
			next=L[cur].parent;
			f[cur]=count;
		}else{
			next=v;
			L[next].parent=cur;
			L[next].checked=1;
			d[next]=count;
		}
	return next;
}

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	
	int n,i,j;
	cin >> n;
	
	vector<Vertex> L(n);
	vector<int> d(n);
	vector<int> f(n);
	
	int id,de,v;
	for (i=0;i<n;i++){
		cin >> id >> de;
		L[id-1].deg=de;
		for (j=0;j<de;j++){
			cin >> v;
			L[id-1].adj.push_back(v-1);
		}
		L[id-1].checked=0;
		L[id-1].parent=-1;
	}
	
	int cur=0;
	int next,count=0;
	
	while(1){
		count++;
		for (i=0;i<n;i++){
			if(L[i].checked==0){
				break;
			}
		}
		if (i==n){
			break;
		}
		L[i].checked=1;
		d[i]=count;
		cur=i;
		while(1){
			count++;
			next=Next(L,d,f,cur,count);
			if (next==-1){
				break;
			}
			cur=next;
		}
		}
	for (i=1;i<n+1;i++){
		cout << i << " " << d[i-1] << " " << f[i-1] <<endl;
	}
	return 0;
}