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++: /**
 * Depth first search.
 * start from node 1
 * 1) increment time 
 * 2) find non visited adjacent node
 * 3) if found move to that node.  d[v'] = time
 * 4) if not found. f[v] = time
 * 5) else end.
 * 5) go to 2.
 */

#include <iostream>
using namespace std;
const int N = 101;
int adj[N][N] = {0};
int d[N]={0};
int f[N]={0};
int t = 1;

void dfs(int n) {
	if (d[n]) return;
	d[n]=++t;
	int k = adj[n][0];
	for (int j=1;j<=k;j++) {
		dfs(adj[n][j]);
	}
	f[n]=++t;
}

int main()
{
	int n;
	cin >> n;
	for (int i=1;i<=n;i++){
		int j, k;
		cin >> j >> k;
		adj[j][0]=k;
		for (int m=1;m<=k;m++) {
			int a;
			cin >> a;
			adj[j][m]=a;
		}
	}

	for (int i=1;i<=n;i++){
		dfs(i);
	}

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

	return 0;
}

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

void dfs(int cur, vector<vector<int> > arr, int d[], int f[], int &time, int n, bool psd[]){
    d[cur] = time;
    time++;
    psd[cur] = true;
    for(int dst = 0; dst < n; dst++){
        if(arr[cur][dst] == 1 && !psd[dst]){
            dfs(dst,arr,d,f,time,n,psd);
        }
    }
    f[cur] = time;
    time++;
}

int main(){
    int n;
    scanf("%d",&n);
    vector<vector<int> > arr(n,vector<int>(n));
    for(int i = 0; i < n; i++){
        for(int j = 0; j < n; j++){
            arr[i][j] = 0;
        }
    }
    for(int i = 0; i < n; i++){
        int u,k;
        scanf("%d %d",&u,&k);
        for(int j = 0; j < k; j++){
            int v;
            scanf("%d",&v);
            arr[u-1][v-1] = 1;
        }
    }
    int d[n],f[n],time = 1;
    bool psd[n];
    for(int i = 0; i < n; i++){
        psd[i] = false;
    }
    for(int cur = 0; cur < n; cur++){
        if(!psd[cur]){
            dfs(cur,arr,d,f,time,n,psd);
        }
    }
    for(int id = 0; id < n; id++){
        printf("%d %d %d\n", id+1, d[id], f[id]);
    }
}

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

class Adjl{
private:
	int u;
	int k;
	Adjl **next;
protected:
	int d;
	int f;
public:
	Adjl(int u);
	~Adjl(){ if (next != NULL) delete[] next; }
	void setV(int k, Adjl *vk);
	int depthFirstSearch(int time);
	void print();
};

Adjl::Adjl(int u)
{
	this->u = u;
	k = 0;
	next = NULL;
	d = 0;
	f = 0;
}

void Adjl::setV(int k, Adjl *vk)
{
	if (this->k == 0) next = new Adjl*[k];
	next[this->k] = vk;
	(this->k)++;
}

int Adjl::depthFirstSearch(int time)
{
	time++;
	d = time;
	for (int i = 0; i < k; i++) {
		if (next[i]->d == 0) {
			time = next[i]->depthFirstSearch(time);
		}
	}
	time++;
	f = time;
	return time;
}

void Adjl::print()
{
	cout << u << " " << d << " " << f << endl;
}

int main(void)
{
	int n;
	cin >> n;
	
	Adjl **adjl = new Adjl*[n];
	int check[100] = {0};

	for (int i = 0; i < n; i++) {
		int u, k;
		cin >> u >> k;
		if (check[i] == 0) {
			adjl[i] = new Adjl(u);
			check[i] = 1;
		}
		check[i] = 1;
		for (int j = 0; j < k; j++) {
			int vk;
			cin >> vk;
			if (check[vk - 1] == 0) {
				adjl[vk - 1] = new Adjl(vk);
				check[vk - 1] = 1;
			}
			adjl[i]->setV(k, adjl[vk - 1]);
		}
	}

	adjl[0]->depthFirstSearch(0);

	for (int i = 0; i < n; i++) {
		adjl[i]->print();
	}

	delete[] adjl;
	return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i,n) for(int i=0; i<(n); i++)
#define FOR(i,a,n) for(int i=(a); i<(n); i++)
#define all(v) v.begin(), v.end()
using namespace std;
typedef long long ll;
const int INF = 1e9;
const int MOD = 1e9+7;

using Graph = vector<vector<int>>;
Graph G;

vector<int> d, f;

int dfs(int v, int t) {
    if(d[v]==0) d[v]=t;
    int res = t;
    for(const auto nv: G[v]) {
        if (d[nv]) continue;
        res = dfs(nv, res+1);
    }
    return f[v] = ++res;
}

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

    int n; cin >> n;
    G.resize(n);
    rep(i, n) {
        int x, k; cin >> x >> k;
        x--;
        rep(j, k) {
            int v; cin >> v; v--;
            G[x].push_back(v);
        }
    }

    d.assign(n, 0); f.assign(n, 0);

    int cur = 1;
    rep(i, n) {
        if (!d[i]) {
            cur = dfs(i, cur);
            cur++;
        }
    }
    rep(i, n) {
        cout << i+1 << " " << d[i] << " " << f[i] << endl;
    }
}