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 <stdio.h>
#include <iostream>
#include <algorithm>

using namespace std;

int G[101][101];
bool Memo[101];
int d[101];
int f[101];
int count1;

void dfs(int i, int n) {
  if (Memo[i]) {
    count1++;
    d[i] = count1;
    Memo[i] = false;
    for (int j = 0; j < n; j++) {
      if (G[i][j] == 1) {
        dfs(j,n);
      }
    }
    count1++;
    f[i] = count1;
  }
}

int main() {
  int n;
  scanf("%d",&n);
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < n; j++) {
      G[i][j] = 0;
    }
  }
  for (int i = 0; i < n; i++) {
    int row,col;
    scanf("%d %d",&row,&col);
    for (int j = 0; j < col; j++) {
      int d;
      scanf("%d",&d);
      G[row - 1][d - 1] = 1;
    }
  }
  for (int i = 0; i < n; i++) Memo[i] = true;
  count1 = 0;
  for (int i = 0; i < n; i++) {
    if (Memo[i]) dfs(i,n);
  }
  for (int i = 0; i < n; i++) printf("%d %d %d\n",i+1,d[i],f[i]);
  return 0;
}

C++: #include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<climits>
#include<iostream>
#include<sstream>
#include<utility>
#include<map>
#include<vector>
#include<queue>
#include<algorithm>
#include<set>
#include<stack>
using namespace std;
typedef long long ll;
typedef pair<int,int>P;
int N,u,k,x,r=0;
vector<int>V[105];
bool f[105]={0};
P c[105];

void dfs(int p)
{
	if(f[p])return;
	r++;
	f[p]=1;
	c[p].first=r;
	for(int i=0;i<V[p].size();i++)
	{
		dfs(V[p][i]);
	}
	r++;
	c[p].second=r;
}

int main()
{
	scanf("%d",&N);
	for(int i=0;i<N;i++)
	{
		scanf("%d%d",&u,&k);u--;
		for(int j=0;j<k;j++)
		{
			scanf("%d",&x);x--;
			V[u].push_back(x);
		}
		sort(V[u].begin(),V[u].end());
	}
	dfs(0);
	for(int i=0;i<N;i++)
		printf("%d %d %d\n",i+1,c[i].first,c[i].second);
	return 0;
}

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

void search(int i,int *table, int n, int *d, int *f, int *cnt){
	
	++(*cnt);
	d[i] = *cnt;
	
	for(int j=0;j<n;++j){
		if(table[i*n+j]){
			for(int k=0;k<n;++k){
				table[k*n+j] = 0;
			}
			search(j,table,n,d,f,cnt);
		}
	}
	
	++(*cnt);
	f[i] = *cnt;
}

int main() {
	int n,*table,*d,*f, cnt;
	
	cin>>n;
	table = new int[n*n];
	d = new int[n];
	f = new int[n];
	
	for(int i=0;i<n;++i){
		int u,k,v;
		cin>>u>>k;
		for(int j=0;j<k;++j){
			cin>>v;
			table[(u-1)*n+v-1]=1;
		}
	}
	cnt = 0;
	
	while(true){
		int rest = 0;
		for(int i=0;i<n;++i){
			for(int j=0;j<n;++j){
				if(table[i*n+j]){
					rest = 1;
					break;
				}
			}
			if(rest){
				search(i,table,n,d,f,&cnt);
				break;
			}
		}
		if(!rest){
			break;
		}
	}
	
	for(int i=0;i<n;++i){
		cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
	}
	
	return 0;
}

C++: #include <cstdio>
using namespace std;
int tim = 0;
bool vis[107];
int G[107][107], d[107], f[107];
void dfs(int cur) {
	vis[cur] = true;
	d[cur] = ++tim;
	for (int i = 0; G[cur][i]; i++) {
		if (!vis[G[cur][i]]) dfs(G[cur][i]);
	}
	f[cur] = ++tim;
}
int main() {
    int n;
    scanf("%d", &n);
    for (int i = 0; i < n; i++) {
    	int u, k;
    	scanf("%d%d", &u, &k);
    	for (int j = 0; j < k; j++) {
    		scanf("%d", &G[u][j]);
		}
	}
	for (int i = 1; i <= n; i++) {
		if (!vis[i]) dfs(i);
	}
	for (int i = 1; i <= n; i++) {
		printf("%d %d %d\n", i, d[i], f[i]);
	}
    return 0;
}

C++: #include<stdio.h>
#define N 100
#define WHITE 0
#define GREY 1
#define BLACK 2

int n, M[N][N];
int color[N], d[N], f[N], time;

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

void dfs()
{
	int u;
	for(u = 0; u < n; u++)
		color[u] = WHITE;
	time = 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()
{
	scanf("%d", &n);
	for(int i = 0; i < n; i++)
		for(int j = 0; j < n; j++)
			M[i][j] = 0;
	int u, k, v;
	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();
}

C++: #include <iostream>
#include <vector>
#include <stack>
#include <cstring>
#define N 101

using namespace std;

int visited[N], nt[N], discovery[N], finish[N], tt, n;
vector<int> G[N];

int next(int u) {
    for (int v = nt[u]; v < G[u].size(); v++) {
        nt[u] = v + 1;
        return G[u][v];
    }
    return -1;
}

void dfs(int r) {
    memset(nt, 0, sizeof(nt));

    stack<int> S;
    S.push(r);

    visited[r] = 1;
    discovery[r] = ++tt;

    while (!S.empty()) {
        int u = S.top();
        int v = next(u);

        if (v != -1) {
            if (visited[v] == 0) {
                visited[v] = 1;
                discovery[v] = ++tt;
                S.push(v);
            }
        }
        else {
            S.pop();
            visited[u] = 1;
            finish[u] = ++tt;
        }
    }
}

int main() {
    int u, k, v;
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> u >> k;
        u--;
        for (int j = 0; j < k; j++) {
            cin >> v;
            v--;
            G[u].push_back(v);
        }
    }

    memset(visited, 0, sizeof(visited));
    tt = 0;

    for (int i = 0; i < n; i++) {
        if (visited[i] == 0) {
            dfs(i);
        }
    }

    for (int i = 0; i < n; i++) {
        cout << i + 1 << " " << discovery[i] << " " << finish[i] << endl;
    }

    return 0;
}