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 <cstdio>

typedef struct{
	bool isVisited;
	int degree;
	int start;
	int end;
	int *neighbors;
} node;

int count = 0;

void dfs(node* nodes, int id){
	nodes[id].isVisited = true;
	if (nodes[id].start == 0) nodes[id].start=count;
	for (int i=0; i<nodes[id].degree; i++){
		if (!nodes[nodes[id].neighbors[i]].isVisited){
			count ++;
			dfs(nodes, nodes[id].neighbors[i]);
		}
	}
	count++;
	nodes[id].end = count;
}

int main(){
	int n, d, r, id;
	node *nodes;

	scanf("%d", &n);
	nodes = new node[n+1];
	nodes[0].start=0;
	nodes[0].degree=n;
	nodes[0].neighbors = new int[n];
	for (int i=0;i<n;i++){
		nodes[0].neighbors[i]=i;
	}
	for (int i=1; i<n+1;i++){
		nodes[i].isVisited=false;
		scanf("%d %d", &r, &d);
		nodes[i].degree=d;
		nodes[i].neighbors = new int[d];
		nodes[i].start = 0;
		
		for (int j=0;j<d;j++){
			scanf("%d", &id);
			nodes[i].neighbors[j] = id;
		}
	}

	dfs(nodes, 0);
	for (int i=1; i<n+1;i++){
		printf("%d %d %d\n", i, nodes[i].start, nodes[i].end);
		delete []nodes[i].neighbors;
	}
	delete []nodes;
	return 0;
}

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

using namespace std;
static const int MAX=101;
bool Visited[MAX]; //??\?????????????¢??????????
vector<int> Adjacency[MAX];
int dTime[MAX]; int fTime[MAX]; //?¢??????°??¶??´????¢?????????¶??´
void dfs(int i,int& clock) //??¶????????°?????\???????????¨
{
    clock++;
    Visited[i]=true;
    dTime[i]=clock; //???????????°??¶??´
    for(int j=0;j<Adjacency[i].size();j++)
    {
        if(Visited[Adjacency[i][j]]==true) continue;
        dfs(Adjacency[i][j],clock);
    }
    clock++; //???????????????????¢????
    fTime[i]=clock;
}

int main()
{
    int n;
    cin>>n;
    for(int i=1;i<=n;i++) Visited[i]=false;

    for(int i=1;i<=n;i++)
    {
        int p;cin>>p;
        int num;
        cin>>num;

        for(int j=0;j<num;j++)
        {
            int t;
            cin>>t;
            Adjacency[p].push_back(t);
        }
    }
    int clock=0;
    for(int i=1;i<=n;i++)  //???????????????????????°DFS?£?????????????
    {
        if(Visited[i]==false) dfs(i,clock);
    }
    for(int i=1;i<=n;i++)
        cout<<i<<' '<<dTime[i]<<' '<<fTime[i]<<endl;
}

C++: #include <cstdio>
#include <cstring>

const int MAX = 100;
static int time = 0;
int adj[MAX][MAX];
int discover[MAX];
int finish[MAX];

void visit(int node, int n)
{
  ++time;
  discover[node] = time;

  for (int i = 0; i < n; ++i)
  {
    if (adj[node][i] == 1 && discover[i] == 0)
      visit(i, n);
  }

  ++time;
  finish[node] = time;
}

int main()
{
  std::memset(adj, 0, sizeof(adj));
  std::memset(discover, 0, sizeof(discover));
  std::memset(finish, 0, sizeof(finish));

  int n;
  scanf("%d", &n);

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

  for (int i = 0; i < n; ++i)
  {
    if (discover[i] == 0)
      visit(i, n);
  }

  for (int i = 0; i < n; ++i)
    printf("%d %d %d\n", i + 1, discover[i], finish[i]);

  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<cstdio>
#include<algorithm>
#include<stack>
using namespace std;
int main(){
    int n,u,k,v;
    int M[100][100];
    stack<int> S;

    cin >> n;
    for(int i=0;i<n;i++){
	cin >> u;
	u--;
	cin >> k;
	for(int j=0;j<k;j++){
	    cin >> v;
	    v--;
	    M[u][v]=1;
	}
    }

    int time=0;
    int d[100]={0},f[100]={0};
    bool found;
    int i;

    S.push(0);
    while(!S.empty()){
	if(d[S.top()]==0) d[S.top()]=++time;
	found=false;
	for(i=0;i<n;i++){
	    if(d[i]==0 && M[S.top()][i]==1){
		found=true;
		break;
	    }
	}
	if(found) S.push(i);
	else {
	    f[S.top()]=++time;
	    S.pop();
	}
    }

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

    return 0;
}