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
		}
	}

	timer := 1
	for {
		startNode := findStartNode(childrenMap, timeRecordMap)
		if startNode > 0 {
			visit(startNode, &timer, childrenMap, timeRecordMap)
		} else {
			break
		}
	}
	for k, v := range timeRecordMap {
		fmt.Printf("%d %d %d\n", k+1, v.discoverTime, v.finishTime)
	}
}

func findStartNode(childrenMap [][]int, timeRecordMap []TimeRecord) int {
	x := -1
	for node, timeRecord := range timeRecordMap {
		if timeRecord.discoverTime < 0 {
			x = node + 1
			break
		}
	}
	if x < 0 {
		return -1
	}

	found := false
	i := 0
	for i < len(childrenMap) {
		children := childrenMap[i]
		for j := 0; j < len(children); j++ {
			if children[j] == x {
				x = j + 1
				found = true
				break
			}
		}
		if found {
			i = 0
		} else {
			i++
		}
	}
	return x
}

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 <cstdio>
#include <iostream>
#include <stack>
using namespace std;

static const int MAX_NUM = 101;

static const int NO_VISIT  = 0;
static const int NOW_VISIT = 1;
static const int END_VISIT = 2;

void DSF(int* matrix, int num)
{
    int i;
    int ttime = 0;
    int stime[MAX_NUM+1] = {0};
    int etime[MAX_NUM+1] = {0};
    int state[MAX_NUM+1] = {0};
    stack<int> S;
    int target, next;
    int *tmp;

    S.push(1);
    ++ttime;
    stime[1] = ttime;
    state[1] = NOW_VISIT;

    while (S.empty() == false) {
        target = S.top();
        for (i = 1; i <= num; i++) {
            tmp = matrix + MAX_NUM * target + i;
            if ((*tmp == 1) && (state[i] == NO_VISIT)) {
                *tmp = 2;
                S.push(i);
                ++ttime;
                stime[i] = ttime;
                state[i] = NOW_VISIT;
                break;
            }
        }

        if (i == num + 1) {
            S.pop();
            ++ttime;
            etime[target] = ttime;
            state[target] = END_VISIT;
        }
    }

    for (i = 1; i <= num; i++) {
        printf("%d %d %d\n", i, stime[i], etime[i]);
    }

    return;
}

int main(void)
{
    int i, j;
    int num;
    int elem;
    int nume;
    int tmp;
    int matrix[MAX_NUM][MAX_NUM] = {0};

    scanf("%d", &num);

    for (i = 0; i < num; i++) {
        scanf("%d %d", &elem, &nume);
        for (j = 0; j < nume; j++) {
            scanf("%d", &tmp);
            matrix[elem][tmp] = 1;
        }
    }

    DSF(&matrix[0][0], num);

    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define ll long long 

int n,t;
vector<int>G[101];
int d[101],f[101];
bool used[101];

void dfs(int v){
  used[v]=true;
  d[v]=++t;
  rep(i,G[v].size()){
    int e=G[v][i];
    if(used[e]==false)dfs(e);
  }
  f[v]=++t;
}

int main(){
  cin>>n;
  rep(i,n){
    int u,k;
    cin>>u>>k;
    u--;
    rep(j,k){
      int v;
      cin>>v;
      v--;
      G[u].push_back(v);
    }
  }
  rep(i,n)if(used[i]==false)dfs(i);
  rep(i,n)cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
  return 0;
}

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

int n, t = 0, d[110] = {}, f[110];
bool a[110][110] = {};

void dfs(int u){
  d[u] = ++t;
  
  for(int i = 1;i <= n;i++) if(a[u][i] && d[i] == 0) dfs(i);
  
  f[u] = ++t;
}

int main(){
  
  int u, k, v;
  
  cin >> n;
  for(int i = 0;i < n;i++){
    cin >> u >> k;
    for(int j = 0;j < k;j++){
      cin >> v;
      a[u][v] = true;
    }
  }
  
  for(int i = 1;i <= n;i++){
    for(int j = 1;j <= n;j++){
      if(a[i][j] && d[i] == 0) dfs(i);
    }
  }
  
  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  //未访问节点
#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,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;
}

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 BRACK = 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????????????
		nt[i] = 0;
	}

	stack<int> S;//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] = BRACK;
			f[u] = ++tt;
		}
	}
}

void dfs() {
	//?????????
	for (int i = 0; i < n; i++) {
		color[i] = WHITE;
		nt[i] = 0;
	}
	tt = 0;

	//????¨???????u????§??????¨????????±???????????¢?´¢
	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++) {//??????M????????????????´?
		cin >> u >> k;
		u--;//0?????????????????????
		for (int j = 0; j < k; j++) {
			cin >> v;
			v--;//0?????????????????????
			M[u][v] = 1;
		}
	}

	dfs();

	return 0;
}