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<iostream>
#include<stack>
#include<vector>
#include<string>
#include<algorithm>

struct node {
	int num;
	std::vector<int> child;
};

int recurcive(node nodes[],int d[100], int f[100], int n, int count) {
	d[n] = count++;
	for (size_t i = 0; i < nodes[n].child.size(); i++) {
		if (d[nodes[n].child[i]] == 0) {
			count = recurcive(nodes, d, f, nodes[n].child[i], count);
		} else {
			nodes[n].child.erase(std::find(nodes[n].child.begin(), nodes[n].child.end(), nodes[n].child[i]));
			i--;
		}
	}
	f[n] = count++;

	return count;
}

int main() {
	int node_num;
	node nodes[100];
	std::cin >> node_num;

	for (int i = 0; i < node_num; i++) {
		int n, num;
		std::cin >> n >> num;
		for (int j = 0; j < num; j++) {
			int val;
			std::cin >> val;
			nodes[n - 1].child.push_back(val - 1);
		}
	}

	std::stack<int> st, st2;
	std::vector<int> gone;
	int d[100], f[100];
	int count = 1;

	for (int i = 0; i < 100; i++)
		d[i] = f[i] = 0;

	for (int i = 0; i < node_num; i++) {
		if (d[i] == 0) {
			count = recurcive(nodes, d, f, i, count);
		}
	}

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

C++: #include<bits/stdc++.h>
using namespace std;

int times;
vector<vector<int> > lists;
vector<int> stampA;
vector<int> stampB;

void dfs(int point){
    times++;
    stampA.at(point-1)=times;
    for(int i=0;i<(int)lists.at(point-1).size();i++){
        if(stampA.at(lists.at(point-1).at(i)-1)==0) dfs(lists.at(point-1).at(i));
    }
    times++;
    stampB.at(point-1)=times;
    
}

int main(){
    times=0;
    int n;
    cin >> n;
    lists.resize(n,vector<int>());
    stampA.resize(n,0);
    stampB.resize(n,0);
    for(int i=0;i<n;i++){
        int u,k;
        cin >> u >> k;
        for(int j=0;j<k;j++){
            int v;
            cin >> v;
            lists.at(u-1).push_back(v);
        }
    }
    
    for(int i=0;i<n;i++){
        if(stampA.at(i)==0) dfs(i+1);
    }
    
    for(int i=0;i<n;i++){
        cout << i+1 << " " << stampA.at(i) << " " << stampB.at(i) << endl;
    }
}

C++: #include <bits/stdc++.h>
#define r(i,a,n) for(int i=a;i<n;i++)
using namespace std;
int a[101][101],start[101],end[101],n,p=0,v[101];
void dfs(int u){
    if(!v[u]){v[u]++;
    start[u]=++p;
    r(i,1,n+1)if(a[u][i])dfs(i);
    end[u]=++p;}
}
int main(){
    int q,qq,qqq;
    cin>>n;
    r(i,0,n){cin>>q>>qq;
        r(i,0,qq){cin>>qqq;
            a[q][qqq]++;
        }
    }
    r(i,1,n+1)if(!v[i])dfs(i);
    r(i,1,n+1)cout<<i<<' '<<start[i]<<' '<<end[i]<<endl;
}

C++: /* ALDS1_11_B: Depth First Search */

#include <iostream>
#include <cstdio>
#include <vector>
using std::vector;

vector<int> *graph;
int elapsed = 1;

// Search the graph recursively by depth-first search.
void traverse(int id, int found[], int finished[]) {
    if (0 < found[id]) {
        return;
    }

    found[id] = elapsed++;
    vector<int> degrees = graph[id];
    for (int i = 0; i < degrees.size(); i++) {
        traverse(degrees[i], found, finished);
    }
    finished[id] = elapsed++;
}

int main() {
    int n_v;
    scanf("%d", &n_v);

    int max_v = n_v + 1;
    graph = new vector<int>[max_v];

    for (int i = 0; i < max_v; i++) {
        int id, n_degrees;
        scanf("%d %d", &id, &n_degrees);

        for (int j = 0; j < n_degrees; j++) {
            int deg_id;
            scanf("%d", &deg_id);
            graph[id].push_back(deg_id);
        }
    }

    int found[max_v];
    int finished[max_v];
    std::fill_n(found, max_v, 0);
    std::fill_n(finished, max_v, 0);

    traverse(1, found, finished);

    for (int id = 1; id < max_v; id++) {
        printf("%d %d %d\n", id, found[id], finished[id]);
    }
    return 0;
}

C++: //#include <bits/stdc++.h>
#include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <cmath>
#include <algorithm>
#include <map>
#include <iomanip>
#include <stdlib.h>
#include <stdio.h>
#include <queue>
#include <deque>
#include <set>
#include <stack>
#include <time.h>
 
using namespace std;
 
typedef long long ll;
typedef long double ld;
typedef pair<int, int> Pii;
typedef pair<int, ll> Pil;
typedef pair<ll, ll> Pll;
typedef pair<ll, int> Pli;
 
const ll MOD = 1e9 + 7;
const ll MOD2 = 998244353;
const ll INF = 1ll << 60;
const double PI = 2 * asin(1);

int N, Start[105], Goal[105];
vector <int> Graph[105];

int Time = 0;
int DFS(int node){
  for (int i = 0; i < Graph[node].size(); i++){
    int next = Graph[node][i];
    if (Start[next] == 0){
      Time++;
      Start[next] = Time;
      DFS(next);
    }
  }
  Time++;
  Goal[node] = Time;
  return 0;
}

int main(){
  cin >> N;
  for (int i = 0; i < N; i++){
    int M, K; cin >> M >> K;
    for (int j = 0; j < K; j++){
      int Node; cin >> Node;
      Graph[M].push_back(Node);
    }
  }

  for (int i = 1; i <= N; i++){
    if (Graph[i].size() > 0) sort(Graph[i].begin(), Graph[i].end());
  }
  
  for (int i = 1; i <= N; i++){
    if (Start[i] == 0){
      Time++; Start[i] = Time; DFS(i);
    }
  }
  

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