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 <algorithm>
#include <iostream>
#include <queue>
#include <vector>
using namespace std;
#define FOR(I,A,B) for(int I = (A); I < (B); ++I)
 
int d[111], f[111];
bool visited[111];
vector<vector<int> > g(111);
int t;
void dfs(int x){
  t++;
  d[x] = t;
  visited[x] = true;
  for(auto &u : g[x]){
    if(!visited[u]){
      dfs(u);
    }
  }
  t++;
  f[x] = t;
}
 
int main(){
  int n; cin >> n;
  FOR(i,0,n){
    int u, k; cin >> u >> k;
    FOR(j,0,k){
      int v;
      cin >> v;
      g[u].push_back(v);
    }
  }
  FOR(i,0,n+1) visited[i] = false;
  t = 0;
  FOR(i,1,n+1){
    if(!visited[i]) dfs(i);
  }
 
  FOR(i,1,n+1){
    printf("%d %d %d\n", i, d[i], f[i]);
  }
  return 0;
}

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

using namespace std; 

int Time;
vector< vector<int> > adj;
vector< pair<int,int> > res;

void dfs(int v) {
	res[v].first = Time;
	for (int i = 0; i < adj[v].size(); ++i) {
		if (res[adj[v][i]].first < 0) {
			++Time;
			dfs(adj[v][i]);
		}
	}
	++Time;
	res[v].second = Time;
	return;
}

int main(void) {
	int nov,noe,u,v;
	cin >> nov;
	adj = vector< vector<int> >(nov);
	for (int i = 0; i < nov; ++i) {
		cin >> u;
		cin >> noe;
		adj[u-1] = vector<int>(noe);
		for (int j = 0; j < noe; ++j) {
			cin >> adj[u-1][j];
			--adj[u-1][j];
		}
	}
	Time = 1;
	res = vector< pair<int,int> >(nov,{-1,-1});
	int start = 0;
	while (start >= 0) {
		dfs(start);
		start = -1;
		++Time;
		for (int i = 0; start < 0 && i < nov; ++i) {
			if (res[i].first < 0) {
				start = i;
			}
		}
	}
	for (int i = 0; i < nov; ++i) {
		cout << i+1 << " ";
		cout << res[i].first << " ";
		cout << res[i].second << endl;
	}
	return 0;
}

C++: #include <iostream>
using namespace std;
int v[101][101];
int node[101][2];
int t=1;
int n;
void dfs(int i){
   
    node[i][0]=t;
    t++;
    for(int i=1;i<=n;i++){
        v[i][1]=0;
    }
    for(int j=1;j<=n;j++){
        if(v[i][j]==1){
            for(int k=1;k<=n;k++){
                v[k][j]=0;
            }
            dfs(j);
        }
    }
    node[i][1]=t;
    t++;
}
int main(void){
    
    cin >> n;
    int x,y,z;
    for(int i=1;i<=n;i++){
        cin >> x>>y;
        for(int j=1;j<=y;j++){
            cin >> z;
            v[i][z]=1;
        }
    }
    dfs(1);
    
   for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            if(v[i][j]==1){
                dfs(i);
            }
        }
    }
    for(int i=1;i<=n;i++){
        cout <<i<< " " <<node[i][0]<<" " <<node[i][1]<<endl;
    }
   
    
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define repR(i, n) for(int i = (n) - 1; i > -1; i--)
#define rep1(i, n) for(int i = 1; i < (int)(n + 1); i++)
#define rep1R(i, n) for(int i = (n); i > 0; i--)
using namespace std;

const int WHITE = 0;
const int GRAY = 1;
const int BLACK = 2;

int n;
int M[110][110] = {};
int color[110];
int elapse = 0;
int d[110];
int f[110];

void dfs(int u) {
  color[u] = GRAY;
  d[u] = ++elapse;
  rep(v, n) {
    if (M[u][v] && color[v] == WHITE) dfs(v);
  }
  color[u] = BLACK;
  f[u] = ++elapse;
}

void dfs_init() {
  rep(i, n) color[i] = WHITE;
  dfs(0);
}

int main() {
  cin >> n;
  rep(i, n) {
    int id, deg;
    cin >> id >> deg;
    --id;    // 0-indexedに直す
    rep(j, deg) {
      int v;
      cin >> v;
      --v;    // 0-indexedに直す
      ++M[id][v];
    }
  }
  dfs_init();
  rep(i, n) {
    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,a[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(a[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++)a[i][j] = 0;
    }
    for(int i = 0;i < n;i++){
        cin >> u >> k;
        u--;
        for(int j = 0;j < k;j++){
            cin >> v;
            v--;
            a[u][v] = 1;
        }
    }
    dfs();
    
    return 0;
}