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<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, tt;
int M[N][N], color[N], d[N], f[N], nt[N]; 

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 = 0;
		while(!M[u][v] && v < n) {
			v++;
		} 
		if(v != n) {
			if(color[v] == WHITE) {
			   color[v] = GRAY;
			   d[v] = ++tt;
			   S.push(v); 	
			}
		} else {
		   color[u] = BLACK;
		   S.pop();
		   f[u] = ++tt;
		}
	} 
}


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

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

int main() {
	int k , u, 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 i = 0; i < k; i++) {
	        cin >> v;
	        v--;
		   M[u][v] = 1; 
     	}
	} 
	
	dfs();
	
	return 0;
}

C++: #include<stdio.h>
#include<stack>
using namespace std;
int begins[100] = {0},ends[100] , a[100][100],f[100]={0};
stack<int> tc;
int cnt = 0;
int n;
void inset(int u){
    int i;
    if(begins[u] != 0)return;
    begins[u] = ++cnt;
    tc.push(u);
 for(i = 1 ;i <= n ; i++){
    if( a[u][i] == 1 )
    {   a[i][u] = 0;
        a[u][i] = 0 ;
     inset(i);
    }
    }
ends[tc.top()] = ++cnt;
tc.pop();
if(tc.empty())return;
}
int main(){
int i , j , k , m , t;
scanf("%d",&n);
for(i = 0  ; i < n ; i ++){
    scanf("%d%d",&m,&k);
    while(k--){
        scanf("%d",&t);a[m][t] = 1;
    }
}
inset(1);
for(i = 1 ; i <= n ; i++){
    printf("%d %d %d\n",i,begins[i],ends[i]);
}
return 0;
}

C++: #include<iostream>

int main(){

  int n,a;
  std::cin>>n;

  int Adj[100][100],adj[100][100]={0},find[100][2],back[100],depth[100]={0},endflag[100]={0},flag;
  int u[n],k[n],kcou=0,timenow=0,v,pred,prev;
  for(int i=0;i<n;i++){
    std::cin>>u[i];
    std::cin>>k[i];
    for(int j=0;j<k[i];j++){
      std::cin>>Adj[i][j];
    }
  }
	
	/*
  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
    	std::cout<<Adj[i][j]<<" ";
    }
  	std::cout<<"\n";
  }*/
	
	v=0;

	while(timenow<n*2){
		flag=0;
		//std::cout<<find[v][0]<<" "<<find[v][1];
		if(find[v][0]==NULL){
			timenow++;
			find[v][0]=timenow;
			flag=1;
			//std::cout<<flag<<" 1";
		}else if(find[v][1]==NULL){
			if(endflag[v]==1){
				timenow++;
				find[v][1]=timenow;
				flag=2;
			}
			//std::cout<<flag<<" 2";
		}else{
			v=back[v];
			flag=3;
			//std::cout<<flag<<" 0";
		}

		if(flag==0){
			pred=depth[v];
			depth[v]++;
			prev=v;
			v=Adj[v][pred]-1;
			back[v]=prev;
			//std::cout<<flag<<"\n";
		}else if(flag==1){
			if(endflag[v]==1){
				depth[v]++;
			}else{
				pred=depth[v];
				depth[v]++;
				prev=v;
				v=Adj[v][pred]-1;
				back[v]=prev;
				//std::cout<<v<<"\n";
			}
		}else if(flag==2){
			v=back[v];
			//std::cout<<flag<<"\n";
		}
		if(depth[v]>k[v]-1){
			endflag[v]=1;
		}
		
	}
	
	
	
	
  for(int i=0;i<n;i++){
     std::cout<<i+1<<" "<<find[i][0]<<" ";
     std::cout<<find[i][1]<<"\n";
    //std::cout<<"\n";
  }

  return 0;
}

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

struct Vertex {
	int id;
	vector<int> vertices;
	int visited;
	int completed;
};

int getNext(Vertex vertices[], int id){
	Vertex v = vertices[id-1];
	int size = v.vertices.size();
	for(int i=0;i<size;i++){
		int nId = v.vertices[i];
		if (vertices[nId-1].visited==-1){
			return nId;
		}
	}
	return -1;
}

void dfs(int n, Vertex vertices[]){
	
	int time = 0;

	for(int i=0;i<n;i++){
		stack<int> st;
		if(vertices[i].visited==-1){
			st.push(vertices[i].id);
		}
		while(!st.empty()){
			int id=st.top();
			if(vertices[id-1].visited==-1){
				vertices[id-1].visited=++time;
			}
			int nId=getNext(vertices,id);
			if(nId!=-1){
				vertices[nId-1].visited=++time;
				st.push(nId);
			} else {
				vertices[id-1].completed=++time;
				st.pop();
			}
		}
	}
}

int main(){
	

	int n;
	cin >> n;
	Vertex vertices[n];

	for(int i=0;i<n;i++){
	
		int id;
		cin >> id;
		vertices[i].id = id;
		vertices[i].visited = -1;
		vertices[i].completed = -1;

		int cnt;
		cin >> cnt;
		for(int j=0;j<cnt;j++){
			cin >> id;
			vertices[i].vertices.push_back(id);
		}
	}
	
	dfs(n,vertices);
	
	for(int i=0;i<n;i++){
		Vertex v = vertices[i];
		cout << v.id << " ";
		cout << v.visited << " ";
		cout << v.completed << endl;
	}

	return 0;
}

C++: #include <algorithm>
#include <cstdio>
#include <functional>
#include <vector>

#define int long long
#define dotimes(i, n) for (int i = 0; i < (n); i++)

using namespace std;

int rint() {
  int n;
  scanf("%lld", &n);
  return n;
}

signed main() {
  int n = rint();
  vector<vector<int> > edges(n);
  dotimes(i, n) {
    int u = rint() - 1;
    int k = rint();
    edges[u].reserve(k);
    dotimes(j, k)
      edges[u].emplace_back(rint() - 1);
    sort(edges[u].begin(), edges[u].end());
  }
  int d[n], f[n];
  fill(d, d + n, 0);
  fill(f, f + n, 0);
  int t = 1;
  function<void(int)> rec;
  rec = [&](int u) {
    if (d[u])
      return;
    d[u] = t++;
    for (auto v : edges[u])
      rec(v);
    f[u] = t++;
  };
  dotimes(u, n) {
    rec(u);
    printf("%lld %lld %lld\n", u+1, d[u], f[u]);
  }
  return 0;
}