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>
#include <vector>
#include <algorithm>
using namespace std;

struct status{
    int idx_node;
    vector<int> children;
    int finded = 0;
    int visited = 0;
};

int step = 0;
vector<status> graph;

void dfs(int now_node){
    ++step;
    graph[now_node-1].finded = step;
    for(auto&& next_node:graph[now_node-1].children){
        if(not graph[next_node-1].finded){
            dfs(next_node);
        }
    }
    ++step;
    graph[now_node-1].visited = step;
}

int main(void){cin.tie(0);ios::sync_with_stdio(false);

    //stdi
    int nb_nodes; cin >> nb_nodes;
    graph.resize(nb_nodes);
    for(auto& times:graph){
        int idx_node; cin >> idx_node; graph[idx_node-1].idx_node = idx_node;
        int nb_edges; cin >> nb_edges; graph[idx_node-1].children.resize(nb_edges);
        for(auto& a:graph[idx_node-1].children){
            cin >> a;
        }
        sort(graph[idx_node-1].children.begin(),graph[idx_node-1].children.end());
    }
    
    //dfs
    int root = 1;
    dfs(root);
    
    //stdo
    for(auto& a:graph){
        cout<<a.idx_node<<" "
            <<a.finded<<" "
            <<a.visited<<"\n";
    }
}

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

int n;
vector<vector<int> > A;
vector<vector<int> > T;
int timer = 0;

void dfs(int cur){
    timer += 1;
    T[cur][0] = timer;

    for(int dst = 0; dst < n; ++dst){
        if(A[cur][dst] == 1 && T[dst][0] == -1){
            dfs(dst);
        }
    }
    timer += 1;
    T[cur][1] = timer;
}

int main(){
    cin >> n;
    A = vector<vector<int> >(n, vector<int>(n, 0));
    T = vector<vector<int> >(n, vector<int>(2, -1));
    for(int i=0; i<n; ++i){
        int k;
        cin >> k;
        k -= 1;
        int u;
        cin >> u;
        for(int j=0; j<u; ++j){
            int v;
            cin >> v;
            v -= 1;
            A[k][v] = 1;
        }
    }
    for(int i=0; i<n; ++i){
        if(T[i][0] == -1){
          dfs(i);
        }
    }
    for(int i=0; i<n; ++i){
        cout << i+1 << " " << T[i][0] << " " << T[i][1] << endl;
    }
}

C++: #include <stdio.h>
#define N 100
#define WHITE 0
#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 <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, start, n) for (int i = (int)(start); i < (int)(n); ++i)
void func(vector<vector<int> > &G, int *d, int *c)
{
    int time(0);
    stack<int> s;
    int count = 0;
    bool check;
    rep(p, 1, G.size())
    {
        if (d[p] == 0)
        {
            do
            {
                // cout << p << endl;
                check = true;
                if (d[p] == 0)
                {
                    s.push(p);
                    d[p] = ++count;
                }
                rep(i, 0, G[p].size())
                {
                    if (d[G[p][i]] == 0)
                    {
                        check = false;
                        p = G[p][i];
                        break;
                    }
                }
                if (check)
                {
                    c[p] = ++count;
                    s.pop();
                    if (s.size())
                        p = s.top();
                    else
                    {
                        p = 0;
                    }
                }
            } while (s.size());
        }
    }
}
int main()
{
    int n;
    cin >> n;
    int u, k, v;
    vector<vector<int> > G(n + 1, vector<int>(0));   //グラフ
    int discover[n + 1] = {}, complete[n + 1] = {}; //発見時刻と完了時刻
    rep(i, 0, n)
    {
        cin >> u >> k;
        rep(j, 0, k)
        {
            cin >> v;
            G[u].push_back(v);
        }
    }
    func(G, discover, complete);
    rep(i, 1, n + 1)
    {
        printf("%d %d %d\n", i, discover[i], complete[i]);
    }
}