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<stdio.h>
#define N 100
#define WHITE 0
#define GRAY 1 
#define BLACK 2
 
int n, M[N][N];
int color[N], d[N], f[N], tt; 

void dfs_visit(int u) {
	int v;
	color[u] = GRAY;
	d[u] = ++tt;
	for(v = 0; v < n; v++) {
		if(M[u][v] == 0) continue;
		if(color[v] == WHITE) {
			dfs_visit(v);
		}
	}
	color[u] = BLACK;
	f[u] = ++tt;
}

void dfs() {
	int u;
	for(u = 0; u < n; u++) color[u] = WHITE;
	tt = 0;
	
	for(u = 0; u < n; u++) {
		if(color[u] == WHITE) dfs_visit(u);
	}
	
	for(u = 0; u < n; u++) {
		printf("%d %d %d\n", u + 1, d[u], f[u]);
	}
}
 
int main() {
    int u, k, v, i, j;
    
    scanf("%d", 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++) {
        scanf("%d %d", &u, &k);
        u--;
        for(int j = 0; j < k; j++ ) {
           scanf("%d", &v);
           v--;
           M[u][v] = 1; 
        }       
    }
     
     
    dfs();
     
    return 0;
}

C++: #include<iostream>
using namespace std;
#include<stdio.h>

int G[101][102];
int found[101];
int comp[101];   // complete.
int t;  // time.

typedef struct box{ int val; box* next; } box_t;  // stack.

box_t* init()
{
    box_t* head = new box_t;
    head->val = -1;
    head->next = NULL;
    return head;
}

bool isEmpty(box_t* head){ return (head->next == NULL ? true : false); }

box_t* push(box_t* head, int data)
{
    box_t* box = new box_t;
    box->val = data;
    box->next = head->next;
    head->next = box;
    return box;
}

int pop(box_t* head)
{
    if(isEmpty(head)){ return -1; }
    box_t* box = head->next;
    int val;
    head->next = box->next;
    val = box->val;
    delete box;
    return val;
}

int front(box_t* head)
{
    int val;
    if(isEmpty(head)){ return -1; }
    val = head->next->val;
    return val;
}

box_t* stack = init();

void search_loop(int i)
{
    int j, k;
    while(1){
        if(found[i] == 0){
            t++; found[i] = t;
            push(stack, i);
        }
        for(k = G[i][0]; G[i][k] != 0 && found[G[i][k]] != 0; k++);
        if(G[i][k] == 0){
            if(isEmpty(stack)){ return; }
            else{
                j = pop(stack);
                t++; comp[j] = t;
                i = front(stack);
            }
        }else{
            G[i][0] = k + 1;
            i = G[i][k];
        }
    };
    return;
}

int main()
{
    int n, i, j, a, b, e;
    scanf("%d", &n);
    for(i = 1; i <= n; i++){
        G[i][0] = 1;
        for(j = 1; j <= n + 1; j++){ G[i][j] = 0; } }

    for(i = 1; i <= n; i++){
        scanf("%d %d", &a, &e);
        for(j = 1; j <= e; j++){
            scanf("%d", &b); G[a][j] = b; } }  // adjacent representation.

    for(i = 1; i <= n; i++){ found[i] = 0; comp[i] = 0; }
    t = 0;
    while(1){
        for(i = 1; i <= n; i++){
            if(found[i] == 0) break;
        }
        if(i > n) break;
        search_loop(i);
    };

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

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

int d[101]={0};
int f[101]={0};
int AdjM[101][101]={0};
int lapse=0;

void dfs(int cur){
    ++lapse;
    d[cur]=lapse;
    //cerr<<"visiting "<<cur<<" "<<lapse<<"\n";
    for(int dst=1;dst<101;++dst){
        if(AdjM[cur][dst]!=0 && d[dst]==0){
            dfs(dst);
        }
    }
    ++lapse;
    f[cur]=lapse;
}

int main(){
    int N;
    cin>>N;
    int id,edgnum,adj;
    for(int i=0;i<N;++i){
        cin>>id>>edgnum;
        for(int j=0;j<edgnum;++j){
            cin>>adj;
            AdjM[id][adj]+=1;
        }
    }

    dfs(1);

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

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

using namespace std;

void dfs(int);
#define N 100
int t = 0;
int s[N], f[N], color[N];
int a[N][N];

int main(int argc, char const *argv[]) {
  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;
      a[u - 1][v - 1] = 1;
    }
  }
  for (int i = 0; i < n; ++i) {
    color[i] = 1;
  }
  for (int i = 0; i < n; ++i) {
    if (color[i] == 1) {
      dfs(i);
    }
  }
  for (int i = 0; i < n; ++i) {
    cout << i + 1 << " " << s[i] << " " << f[i] << '\n';
  }

  return 0;
}

void dfs(int x) {
  color[x] = 2;
  s[x] = ++t;
  for (int i = 0; i < N; ++i) {
    if (a[x][i] == 0) {
      continue;
    }
    if (color[i] == 1) {
      dfs(i);
    }
  }
  color[x] = 3;
  f[x] = ++t;
}

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

const int MAX_N = 100;
vector<int> G[MAX_N];
int d[MAX_N], f[MAX_N];
bool used[MAX_N];

int stamp;

void dfs(const int v) {
    d[v] = stamp++;
    used[v] = true;
    for(int i = 0; i < (int)G[v].size(); i++) {
        int u = G[v][i];
        if(used[u] == false) dfs(u);
    }
    f[v] = stamp++;
}

int main() {
    int N; cin >> N;
    for(int i = 0; i < N; i++) {
        int u, k; cin >> u >> k; u--;
        while(k--) {
            int v; cin >> v; v--;
            G[u].push_back(v);
        }
        sort(G[u].begin(), G[u].end());
    }

    fill(used, used + N, false);
    stamp = 1;
    for(int i = 0; i < N; i++) {
        if(used[i] == false) dfs(i);
    }

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