Go: package main

/*
深さ優先探索
*/

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

func main() {
	scanner := makeScanner(8192)
	n := eGetInt(scanner)
	g := make([][]int, n+1)
	for i := 1; i < n+1; i++ {
		ints := eGetInts(scanner)
		num, vcount := ints[0], ints[1]
		g[i] = make([]int, vcount)
		for j := 0; j < vcount; j++ {
			g[num][j] = ints[j+2]
		}
	}
	hist := make([]struct{ d, f int }, n+1)
	t := 0
	var visit func(int)
	visit = func(num int) {
		if hist[num].d == 0 {
			stack := []int{}
			t++
			hist[num].d = t
			stack = append(stack, num)
			for len(stack) > 0 {
				// トップを訪問する
				top := stack[len(stack)-1]
				for i := 0; i < len(g[top]); i++ {
					if hist[g[top][i]].d == 0 {
						t++
						hist[g[top][i]].d = t
						stack = append(stack, g[top][i])
						goto endloop
					}
				}
				// 訪問場所がなくなったら
				// pop
				stack = stack[0 : len(stack)-1]
				t++
				hist[top].f = t
			endloop:
			}
		}
	}
	for i := 1; i < n+1; i++ {
		visit(i)
	}
	for i := 1; i < n+1; i++ {
		fmt.Println(i, hist[i].d, hist[i].f)
	}
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetInt64(r *bufio.Scanner) int64 {
	line := eGetLine(r)
	return eAtoInt64(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetInt64s(r *bufio.Scanner) []int64 {
	fields := eGetFields(r)
	ints := make([]int64, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoInt64(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}
func eAtoInt64(s string) int64 {
	n, err := strconv.ParseInt(s, 10, 64)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

C++: #include <iostream>
#include <vector>


class Graph {
public:
    std::vector<int> d, v;
    std::vector<std::vector<int>> arr;
    int n;
    int tp = 1;

    Graph(int n) : n(n) {
        d = std::vector<int>(n, 0);
        v = std::vector<int>(n, 0);
        arr = std::vector<std::vector<int>>(n);
    }
    
    void depth_search(int i) {
        if (d[i] == 0) {
            d[i] = tp;
            tp++;
            for (auto j : arr[i]) {
                depth_search(j - 1);
            }
            v[i] = tp;
            tp++;
        }
    }

    void print() {
        for (int i = 0; i < n; i++) {
            std::cout << i + 1 << " " << d[i] << " " << v[i] << std::endl;
        }
    }
};


int main() {
    int n;
    std::cin >> n;

    Graph graph(n);
    
    for (int i = 0; i < n; i++) {
        int u, k;
        std::cin >> u >> k;
        std::vector<int> vs(k);
        
        for (int i = 0; i < k; i++) {
            std::cin >> vs[i];
        }
        graph.arr[u - 1] = vs;
    }

    for (int i = 0; i < n; i++) {
        graph.depth_search(i);
    }

    graph.print();

}

C++: #include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

vector<int> d(101, -1), f(101, -1);
vector<vector<int> > c;

int n, u, k, v;
int dfs(int node, int time) {
    d[node] = time;
    for(int i=0; i<n; ++i) {
        if(c[node][i]==1&&d[i]==-1) time = dfs(i, time+1);
    }
    time++;
    f[node] = time;
    return time;
}

int main() {
    cin >> n;
    for(int i=0; i<n; ++i) {
        cin >> u >> k;
        vector<int> tmp(100, 0);
        for(int j=0; j<k; ++j) {
            cin >> v;
            tmp[v-1] = 1;
        }
        c.push_back(tmp);
    }

    bool isFinished = false;
    int node = 0;
    int time = 1;
    while(isFinished==false) {
        time = dfs(node, time);
        isFinished = true;
        for(node=0; node<n; node++) {
            if(d[node]==-1) {
                isFinished=false;
                break;
            }
        }
    }
    for(int i=0; i<n; ++i) {
        cout << i+1 << " " << d[i] << " " << f[i] << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <map>
#include <cmath>
#include <set>
#include <algorithm>
#include <iomanip>

typedef long long ll;
const ll MOD = 1e9 + 7;
const long long INF = 1LL<<60;
const double PI=3.14159265358979323846;
const int NMAX=100005;
using namespace std;

set<int> to[101];
vector<int> from[101];
vector<int> d(101);
vector<int> f(101);

int dfs(int n, int t){
    if(d[n] != -1) return t-1;
    d[n] = t;
    for(auto it = to[n].begin(); it != to[n].end(); it++){
        t = dfs((*it),t+1);
    }
    t++;
    f[n] = t;
    return t;
}

int main(){
    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;
            cin >> v;
            to[u].insert(v);
            from[v].push_back(u);
        }
        d[u] = -1;
        f[u] = -1;
    }
    
    int t = dfs(1,1);
    for(int i = 1; i <= n; i++){
        if(d[i] == -1){
            t = dfs(i,t+1);
        }
    }

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

    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define rp(i,j) for(long long i=0;i<j;i++)
#define rep(i,j,k) for(long long i=j;i<k;i++)
#define mod 1000000007
#define NIL -1
#define white 0
#define gray 1
#define black 2
typedef long long ll;
int n,tt=0,d[100],f[100];
int a[100][100]={0};
int nt[100]={1};
int color[100]={0};
void dfs_visit(int u){
    color[u]=gray;
    d[u]=++tt;
    rp(v,n){
        if(a[u][v]==0)continue;
        if(color[v]==white){
            dfs_visit(v);
        }
    }
    color[u]=black;
    f[u]=++tt;
}
void dfs(){
    rp(u,n){
        if(color[u]==white)dfs_visit(u);
    }
    rp(u,n){
        cout<<u+1<<" "<<d[u]<<" "<<f[u]<<endl; 
    }
}
int main(){
    int u,k,v;
    cin>>n;
    rp(i,n){
        cin>>u>>k;
        u--;
        rp(j,k){
            cin>>v;
            v--;
            a[u][v]=1;
        }
    }
    dfs();
    return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#include<bitset>
#include<vector>
#include<deque>
#include<queue>
#include<map>
#include<set>
#include<stack>
#include<cmath>
#include<iomanip>
#include <functional>
using namespace std;
typedef long long ll;
const int mod = 1000000007;
const int INF = 1 << 28;
//cout << fixed << std::setprecision(9)
//memset(a, 0, sizeof(a));
//--------------------------

int n;
bool g[110][110];
int d[110];
int f[110];

void dfs(int s)
{
	stack<int> stk;
	d[s] = 0;
	stk.push(s);
	int current = 0;
	while (!stk.empty()) {
		int u = stk.top();
		int flag = 0;
		for (int j = 1; j <= n; j++) {
			if (g[u][j] && d[j] == -1) {
				flag = 1;
				stk.push(j);
				d[j] = ++current;
				break;
			}
		}

		if (flag == 0) {
			f[u] = ++current;
			stk.pop();
		}

	}
}

int main()
{
	cin >> n;
	for (int i = 0; i < n; i++) {
		int u, k, v;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			cin >> v;
			g[u][v] = true;
		}
	}

	for (int i = 1; i <= n; i++) {
		d[i] = -1;
		f[i] = -1;
	}

	dfs(1);

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

	return 0;
}