Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	f         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []*DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]*DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes] = &DirectedGraphNode{}
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].f = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

var time = 0

func fillDistancesByDepthFirstSearch(g *DirectedGraph) {
	for _, u := range g.nodes[1:] {
		if !u.visited {
			dfsVisit(g, u)
		}
	}
}

func dfsVisit(g *DirectedGraph, u *DirectedGraphNode) {
	time++
	u.d = time

	u.visited = true
	for _, v := range u.adjacents {
		if !v.visited {
			v.parent = u
			dfsVisit(g, v)
		}
	}
	time++
	u.f = time
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	fillDistancesByDepthFirstSearch(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		fmt.Println(node.key, node.d, node.f)
	}
}

C++: #include<iostream>
using namespace std;
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 1

int n, M[N][N];
int color[N], s[N], f[N], ts; 

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

void dfs() {
    int u;
    for (u=0; u<n; u++) {
        color[u] = WHITE;
    }
    ts = 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, s[u], f[u]);
    }
}

int main() {
    int u, k, tmp;
    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;
        for (int j=0; j<k; j++) {
            cin >> tmp;
            M[u-1][tmp-1] = 1;
        }
    }
    dfs();
    return 0;
}

C++: #include <vector>
#include <iostream>
#include <set>
#include <cstdio>
#include <queue>
#include <cstdio>
#include <cstdlib>
#include <cassert>
#include <ctime>
#include <cmath>
#include <complex>
#include <algorithm>
#include <tuple>
#include <algorithm>
#include <limits>
#include <map>

using namespace std;

typedef long long ll;
typedef pair<int, int> P;
typedef tuple<int, int, int> T;

int d[110], f[110];
vector<int> g[110];
int t;
bool used[110];
void solve(int i, int b) {
    if (used[i]) return;
    used[i] = true;
    t++;
    d[i] = t;
    for (int j: g[i]) {
        if (j == b) continue;
        solve(j, i);
    }
    t++;
    f[i] = t;
}

int main() {
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
        int id, u;
        cin >> id >> u;
        for (int j = 0; j < u; j++) {
            int a;
            cin >> a;
            g[id].push_back(a-1);
        }
    }
    t = 0;
    fill_n(used, 110, false);
    solve(0, -1);
    for (int i = 0; i < n; i++) {
        printf("%d %d %d\n", i+1, d[i], f[i]);
    }
    return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

using ll = long long;
using P = pair<ll, ll>;
using Graph = vector<vector<ll>>;
#define rep(i, n) for(ll i=0;i<(ll)(n);i++)
#define rep2(i, m, n) for(ll i=m;i<(ll)(n);i++)
#define rrep(i, n, m) for(ll i=n;i>=(ll)(m);i--)
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};
const int ddx[8] = {0, 1, 1, 1, 0, -1, -1, -1};
const int ddy[8] = {1, 1, 0, -1, -1, -1, 0, 1};
const ll MOD = 1000000007;
const ll INF = 1000000000000000000L;
#ifdef __DEBUG

/**
 * For DEBUG
 * https://github.com/ta7uw/cpp-pyprint
 */
#include "cpp-pyprint/pyprint.h"

#endif

vector<ll> d, f;

void dfs(Graph &graph, ll u, ll pre, ll &c) {
    d[u] = c;
    c++;
    sort(graph[u].begin(), graph[u].end());
    for (ll v : graph[u]) {
        if (d[v] == 0) {
            dfs(graph, v, u, c);
            c++;
        }
    }
    f[u] = c;
}

void Main() {
    ll N;
    cin >> N;
    Graph graph(N);
    d.assign(N, 0);
    f.assign(N, 0);
    rep(i, N) {
        ll u, k;
        cin >> u >> k;
        u--;
        rep(j, k) {
            ll v;
            cin >> v;
            v--;
            graph[u].push_back(v);
        }
    }
    ll v = 1;
    rep(i, N) {
        if (d[i] == 0) {
            dfs(graph, i, -1, v);
            v++;
        }
    }
    rep(i, N) {
        cout << i + 1 << ' ';
        cout << d[i] << ' ';
        cout << f[i] << '\n';
    }
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(15);
    Main();
    return 0;
}

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

int n, t = 0;
int A[101][101];
int d[101], f[101];

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

int main() {
	int u, v, l;
	cin >> n;

	for (int i = 1; i <= n; i++) {
		d[i] = f[i] = 0;
	}

	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= n; j++) {
			A[i][j] = 0;
		}
	}

	for (int i = 1; i <= n; i++) {
		cin >> u >> l;
		for (int j = 0; j < l; j++) {
			cin >> v;
			A[u][v] = 1;
		}
	}

	for (int i = 1; i <= n; i++) {
		if (d[i] == 0) dfs(i);
	}

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

	return 0;
}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <string>
#include <algorithm>
#include <utility>
#include <climits>
#include <cstring>
#include <cstdio>

using namespace std;
typedef long long int llg;

const int INF = 1000001000;
#define REP(var, count) for(int var=0; var<count; var++)

template <typename T>
using reverse_queue = std::priority_queue<T, std::vector<T>, std::greater<T> >;

template<typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val){
	std::fill( (T*)array, (T*)(array+N), val );
}

vector<int> rin[105];
pair<int, int> res[105];

int dfs(int a, int time) {
	res[a].first = time;
	for ( int r : rin[a] ) {
		if ( res[r].first != -1 ) { continue; }
		time = dfs(r, time + 1);
	}
	res[a].second = time + 1;
	return res[a].second;
}

int main(void) {
	int N;
	cin >> N;
	
	for(int i=1; i<=N; i++) {
		rin[0].push_back(i);
	
		res[i].first = -1;
		res[i].second = -1;
		
		int U, K;
		cin >> U >> K;
		REP(j, K) {
			int x;
			cin >> x;
			rin[U].push_back(x);
		}
	}
	
	dfs(0, 0);
	
	for(int i=1; i<=N; i++) {
		printf("%d %d %d\n", i, res[i].first, res[i].second);
	}
}