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
	startNode := 1
	for {
		visit(startNode, &timer, childrenMap, timeRecordMap)
		startNode = findStartNode(childrenMap, timeRecordMap)
		if startNode < 0 {
			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
		}
	}
	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<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)//未訪問なら訪問
            {
                color[v]=GRAY;
                d[v]=++tt;
                S.push(v);
            }
        }
        else
        {
            S.pop();//もどる
            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 <iostream>
#include <queue>

using namespace std;

int G[100][100];
int In[100];
int Out[100];
void init() {
	for (int i = 0; i < 100; i++) {
		for(int j = 0; j < 100; j++)
			G[i][j] = 0;
		In[i] = -1;
		Out[i] = -1;
	}	
}

void dfs(int src);

int main() {
	init();
	int n;
	cin >> n;
	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			int v_j;
			cin >> v_j;
			G[u - 1][v_j - 1] = 1;
		}
	}
	dfs(0);
	for (int i = 0; i < n; i++)
		cout << i + 1 << " " << In[i] << " " << Out[i] << endl;
}

int t = 1;

void dfs(int cur) {
	In[cur] = t;
	t++;
	for (int dst = 0; dst < 100; dst++)
		if (G[cur][dst] == 1 && In[dst] == -1)
			dfs(dst);
	Out[cur] = t;
	t++;
}

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

#define N 100
// 未訪問
#define WHITE 0
// 訪問中
#define GRAY 1
// 訪問済み
#define BLACK 2

int n,M[N][N];
int color[N];
// 訪問時間
int d[N];
// 探索終了時間
int f[N];
// 時間
int t = 0;
// 探索済みの頂点を一から探索しないように、nt[u]にすでに探索済みの番号を入れ、次回は探索した移行の頂点から探索されるようにする
int nt[N];

/**
    uに隣接するvを番号順に取得する
*/
int next(int u){
    // 探索済み移行の頂点から探索を始める
    for(int v = nt[u];v < n;++v){
        nt[u] = v + 1;
        if(M[u][v]){
            return v;
        }
    }
    return -1;
}

/**
    スタックを用いた深さ優先探索
*/
void dfs(int u){
    for(int i = 0;i < n;++i){
        nt[i] = 0;
    }
    
    stack<int> S;
    S.push(u);
    color[u] = GRAY;    // 訪問中
    d[u] = ++t;      // 訪問時間
    
    while(!S.empty()){
        int topU = S.top();
        // 隣接する頂点
        int v = next(topU);
        // 隣接する頂点が見つかった場合
        if(v != -1){
            // 未探索のケース
            if(color[v] == WHITE){
                color[v] = GRAY;
                // 訪問時間
                d[v] = ++t;
                S.push(v);
            }
        }else{
            // 未訪問の頂点が見つからなかった
            S.pop();
            // 探索終了
            color[topU] = BLACK;
            // 探索終了時間
            f[topU] = ++t;
        }
    }
}

int main(){
    int u,k,v;
    cin >> n;
    
    // 初期化
    for(int i = 0;i < n;++i){
        color[i] = WHITE;
        for(int j = 0;j < n;++j){
            M[i][j] = 0;
        }
    }
    
    for(int i = 0;i < n;++i){
        cin >> u >> k;
        // 頂点を移動する
        u--;
        // 頂点の数だけ回す
        for(int j = 0;j < k;++j){
            cin >> v;
            --v;    // ずらす
            M[u][v] = 1;
        }
    }
    for(int i = 0;i < n;++i){
        if(color[i] == WHITE){
            dfs(i);
        }
    }
    
    for(int i = 0;i < n;++i){
        cout << i + 1 << " " << d[i] << " " << f[i] << endl;
    }
    
    return 0;
}