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 <bits/stdc++.h>
using namespace std;

void dfs(int& time,
    int start,
    const vector<vector<int>>& graph,
    vector<int>& arraialTimes,
    vector<int>& leftTimes,
    vector<bool>& checkList)
{
    stack<int> stack;
    stack.push(start);
    checkList[start] = true;
    arraialTimes[start] = ++time;
 
    while (!stack.empty())
    {
        int v = stack.top();
        int vSize = 0;
        for (int w : graph[v]) {
            if (!checkList[w]) {
                ++vSize;
                stack.push(w);
                checkList[w] = true;
                arraialTimes[w] = ++time;
                break;
            }
        }
        if (vSize == 0) {
            stack.pop();
            leftTimes[v] = ++time;
        }
    }
}

int main() {
    int n;
    cin >> n;
    vector<vector<int>> graph(n);
    vector<bool> checkList(n);
    vector<int> arrivalTimes(n);
    vector<int> leftTimes(n);


    graph.reserve(n);
    for (auto& g : graph) {
        int id;
        cin >> id;
        int size;
        cin >> size;
        for (int j = 0; j < size; ++j) {
            int k;
            cin >> k;
            g.push_back(k-1);
        }
    }
    int time = 0;
    for (int i = 0; i < n; ++i) {
        if (!checkList[i]) {
            dfs(time, i, graph, arrivalTimes, leftTimes, checkList);
        }
    }
    for (int i = 0; i < n; ++i) {
        cout << i+ 1 << " " << arrivalTimes[i] << " " << leftTimes[i]<< endl;
    }

}

C++: #include <iostream>
#include <cstdio>
#include <cstring>
#include <stack>
using namespace std;
const int maxx = 110;
int n, m[maxx][maxx];
int u, num, v;
int d[maxx], f[maxx];
int flag[maxx];
int nowtime = 1;

void dfs(int u) {

    // 入栈时间
    flag[u] = 1;
    d[u] = nowtime++;
    for (int i = 1; i <= n; i++) {
        if (flag[i] == 0 && m[u][i] == 1) {
            dfs(i);
        }
    }
    //出栈时间
    f[u] = nowtime++;
}

int main()
{

    scanf("%d", &n);
    memset(m, 0, sizeof(m));
    memset(f, 0, sizeof(f));
    for (int i = 1; i <= n; i++) {
        scanf("%d %d", &u, &num);
        for (int j = 1; j <= num; j++) {
            scanf("%d", &v);
            m[u][v] = 1;
        }
    }
    for (int i = 1; i <= n; i++) {
        if(flag[i] == 0)
            dfs(i);
    }
    for (int i = 1; i <= n; i++) {
        printf("%d %d %d\n", i, d[i], f[i]);
    }
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
int n,lis[111][111]={},d[111]={},f[111],t=1;

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

int main(){
  cin>>n;
  for(int c=0;c<n;c++){
    int u,k,v;
    cin>>u>>k;
    for(int i=0;i<k;i++){
      cin>>v;
      lis[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<stack>
#include<vector>
#include<string>

struct node {
	int num;
	std::vector<int> child;
};

int recurcive(node nodes[],int d[100], int f[100], int n, int count) {
	d[n] = count++;
	for (size_t i = 0; i < nodes[n].child.size(); i++) {
		if (d[nodes[n].child[i]] == 0) {
			count = recurcive(nodes, d, f, nodes[n].child[i], count);
		} else {
			nodes[n].child.erase(std::find(nodes[n].child.begin(), nodes[n].child.end(), nodes[n].child[i]));
		}
	}
	f[n] = count++;

	return count;
}

int main() {
	int node_num;
	node nodes[100];
	std::cin >> node_num;

	for (int i = 0; i < node_num; i++) {
		int n, num;
		std::cin >> n >> num;
		for (int j = 0; j < num; j++) {
			int val;
			std::cin >> val;
			nodes[n - 1].child.push_back(val - 1);
		}
	}

	std::stack<int> st, st2;
	std::vector<int> gone;
	int d[100], f[100];
	int count = 1;

	for (int i = 0; i < 100; i++)
		d[i] = 0;

	recurcive(nodes, d, f, 0, 1);

	for (int i = 0; i < node_num; i++) {
		std::cout << i + 1 << " " << d[i] << " " << f[i] << std::endl;
	}
	
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define int long long 

int d[110],f[110];
bool visited[110];
int timestamp = 1;

int n; vector<vector<int>> to;

void dfs(int u){
  if( visited[u] ){ return ;}
  visited[u] = true;
  d[u] = timestamp;
  timestamp++;
  for(auto ne : to[u]){
    if(visited[ne]){continue;}
    dfs(ne);
  }
  f[u] = timestamp;
  timestamp++;
  
  return ;
}
  

signed main(void){
  cin >> n;
  to.resize(n);
  for(int i = 0; i < n; i++){
    int u,k; cin >> u >> k; u--;
    for(int j = 0; j < k; j++){
      int a; cin >> a; a--;
       to[u].push_back(a);
    }
  }
  
  for(int i = 0; i < n; i++){ 
    sort(to[i].begin(),to[i].end());
  }
  
  for(int i = 0; i < n; i++){ dfs(i);}
  
  for(int i = 0; i < n; i++){ cout << i+1 << " " << d[i] << " "<< f[i] << endl;}
  
  return 0;
}