Go: package main

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

type TimeRecord struct {
	discoverTime int
	finishTime   int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	timeRecordMap := make([]TimeRecord, n)
	childrenMap := make([][]int, n)
	for i := 1; i <= n; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		timeRecordMap[node-1] = TimeRecord{-1, -1}

		childNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		childrenMap[node-1] = make([]int, childNum)
		for j := 0; j < childNum; j++ {
			child, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			childrenMap[node-1][j] = child
		}
	}

	// TODO: always start with 1?
	timer := 1
	visit(1, &timer, childrenMap, timeRecordMap)
	for k, v := range timeRecordMap {
		fmt.Printf("%d %d %d\n", k+1, v.discoverTime, v.finishTime)
	}
}

func visit(currentNode int, timer *int, childrenMap [][]int, timeRecordMap []TimeRecord) {
	if timeRecordMap[currentNode-1].discoverTime > 0 {
		return
	}
	children := childrenMap[currentNode-1]
	timeRecordMap[currentNode-1] = TimeRecord{*timer, timeRecordMap[currentNode-1].finishTime}
	(*timer)++
	for i := 0; i < len(children); i++ {
		visit(children[i], timer, childrenMap, timeRecordMap)
	}
	timeRecordMap[currentNode-1] = TimeRecord{timeRecordMap[currentNode-1].discoverTime, *timer}
	(*timer)++
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: #include <sstream>
#include <string>
#include <vector>
#include <map>
#include <algorithm>
#include <iostream>
#include <utility>
#include <set>
#include <cctype>
#include <queue>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cmath>
using namespace std;

#define MAXN 100
int n, timecount = 1;
int ans[MAXN][MAXN];
int d[MAXN], f[MAXN]; // d[i]はdを最初に発見した時刻,f[i]は調べ終わった時刻
bool is_reach[MAXN];

int dfs(int p);

int main(void) {
    cin >> n;
    for (int i = 0; i < n; i++) {
        d[i] = -1;
        f[i] = -1;
        is_reach[i] = false;
    }
    for (int i = 0; i < n; i++)
        for (int j = 0; j < n; j++)
            ans[i][j] = 0;
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int tmp;
            cin >> tmp;
            ans[u-1][tmp-1] = 1;
        }
    }
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (j == n-1) cout << ans[i][j];
            else cout << ans[i][j] << " ";
        }
        cout << endl;
    }
    int start = 0;
    while (1) {
        dfs(start);
        int i;
        printf("%d search end\n", start);
        for (i = 0; i < n; i++) {
            if (f[i] == -1) {
                start = i;
                break;
            }
        }
        if (i == n) break;
        printf("next: %d\n", start);
    }
    for (int i = 0; i < n; i++) {
        printf("%d %d %d\n", i+1, d[i], f[i]);
    }
    return 0;
}

int dfs(int p)
{
    int ret = 0, count = 1;
    is_reach[p] = true;
    if (d[p] == -1) d[p] = timecount++;
    for (int i = 0; i < n; i++) {
        if (ans[p][i] == 1 && is_reach[i] == false && p != i) {
            dfs(i);
        }
    }
    if (f[p] == -1) f[p] = timecount;
    timecount++;
    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 <bits/stdc++.h>
using namespace std;

vector<bool> seen;
vector<int> d;
vector<int> f;

void dfs(const vector<vector<int>> &G, int v, int &time){
    seen[v] = true;
    d[v] = time;
    time++;

    for(auto next_v: G[v]){
        if(seen[next_v]) continue;
        dfs(G, next_v, time);
    }

    f[v] = time;
    time++;
}

int main(){
    int n;
    cin >> n;
    vector<vector<int>> G(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);
        }
    }


    int time = 1;
    seen.assign(n, false);
    d.resize(n);
    f.resize(n);
    
    for(int i = 0; i < n ; i++){
        if(!seen[i]) dfs(G, i, time);
    }

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

C++: #include <iostream>
#include <cstring>
#include <cstdlib>
#include <sstream>
#include <stack>
#include <queue>
#include <list>
#include <stdio.h>
#include <algorithm>
#define MAX 100000
using namespace std;
typedef long long ll;
int map[255][255];
int f[255],d[255],time;
bool vis[255];
void dfs(int n,int u)
{
	if(vis[u]) return;
	vis[u]=true;
	d[u]=++time;
	for(int i=1;i<=n;i++)
	{
		if(map[u][i]) dfs(n,i);
	}
	f[u]=++time;
	return; 
}
int main()
{	
	int n;
	cin>>n;
	for(int i=1;i<=n;i++)
		for(int j=1;j<=n;j++)
		{
			map[i][j]=0;
		}
	for(int i=0;i<n;i++)
	{
		int cur,k,u;
		cin>>cur>>k;
		while(k--)
		{
			cin>>u;
			map[cur][u]=1;
		}
	}
	for(int i=1;i<=n;i++)
	{
		vis[i]=false;
	}
	dfs(n,1);
	for(int i=1;i<=n;i++)
	{
		cout<<i<<" "<<d[i]<<" "<<f[i]<<endl;
	}
	return 0;
}

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;

// 再帰関数による深さ優先探索
void dfs_visit(int u) {
  int v;
  color[u] = GRAY;
  d[u] = ++tt;  // 最初の訪問
  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;  // 訪問の完了
}

void dfs() {
  int u;
  // 初期化
  for ( u = 0; u < n; u++ ) color[u] = WHITE;
  tt = 0;

  for ( u = 0; u < n; u++ )
    // 未訪問の u を始点として深さ優先探索
    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, v, k, i, j;

  scanf("%d", &n);
  for ( i = 0; i < n; i++ )
    for ( j = 0; j < n; j++ ) M[i][j] = 0;

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

  dfs();

  return 0;
}