Go: package main

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

type vertexId int

type vertex struct {
	id vertexId
	firstVisitAt int
	finishVisitAt int
	adjs []vertexId
}

func createVertex(id int, adjsInt []int) vertex {
	adjs := make([]vertexId, len(adjsInt))
	for i := 0; i < len(adjs); i++ {
		adjs[i] = vertexId(adjsInt[i])
	}
	return vertex{
		id: vertexId(id),
		firstVisitAt: 0,
		finishVisitAt: 0,
		adjs: adjs,
	}
}

func (v *vertex) isVisited() bool {
	return v.firstVisitAt > 0
}

func dfs(currentId vertexId, timestamp int, vertices []vertex) int {
	currentVertex := &vertices[currentId-1]
	if currentVertex.isVisited() {
		return timestamp
	}
	timestamp = timestamp + 1
	currentVertex.firstVisitAt = timestamp
	for _, adjId := range currentVertex.adjs {
		timestamp = dfs(adjId, timestamp, vertices)
	}
	timestamp = timestamp + 1
	currentVertex.finishVisitAt = timestamp
	return timestamp
}

func solveDfs(vertices []vertex) {
	timestamp := 0
	for {
		vid := vertexId(-1)
		for i := 0; i < len(vertices); i++ {
			if !vertices[i].isVisited() {
				vid = vertexId(i+1)
				break
			}
		}
		if vid > 0 {
			timestamp = dfs(vid, timestamp, vertices)
		} else {
			break
		}
	}
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	vertices := make([]vertex, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjN, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjs := make([]int, adjN)
		for j := 0; j < adjN; j++ {
			adjId, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			adjs[j] = adjId
		}
		vertices[i] = createVertex(id, adjs)
	}

	solveDfs(vertices)

	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", vertices[i].id, vertices[i].firstVisitAt, vertices[i].finishVisitAt)
	}
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func nextInt(sc *bufio.Scanner) (int, error) {
	return strconv.Atoi(nextText(sc))
}

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

using namespace std;

#define MAX 110
int num;
int matrix[MAX][MAX];
int dst[MAX];

void input(){
    for(int i=0;i<MAX;i++){
        dst[i] = -1;
        for(int j=0;j<MAX;j++){
            matrix[i][j] = 0;
        }
    }
    for(int i=1;i<=num;i++){
        int v; cin >> v;
        int tmp; cin >>tmp;
        for(int j=0;j<tmp;j++){
            int vi; cin >> vi;
            matrix[v-1][vi-1] = 1;
        }
    }
}

void bfs(){
    stack<int> S;
    S.push(0);
    dst[0] = 0;
    while(S.size() != 0){
        int cur = S.top();
        for(int i=0;i<num;i++){
            if(matrix[cur][i]==1){
                if(dst[i]==-1){
                    S.push(i);
                    dst[i] = dst[cur] + 1;
                }
            }
        }
        S.pop();
    }
    for(int i=0;i<num;i++){
        cout << i+1 << " " <<  dst[i] << endl;
    }
}

int main(){
    cin >> num;
    input();
    bfs();
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (n); i++)
using namespace std;
using ll = long long;
using pii = pair<int, int>;

vector<vector<int>> g;
vector<int> d, f;

void dfs(int v, int &t) {
	d[v] = t++;
	for (auto nv : g[v]) {
		if (d[nv]) continue;
		dfs(nv, t);
	}
	f[v] = t++;
}

int main() {
	int n;
	cin >> n;
	g.resize(n);
	rep(i, n) {
		int u, k;
		cin >> u >> k;
		u--;
		rep(i, k) {
			int v;
			cin >> v;
			v--;
			g[u].push_back(v);
		}
	}
	d.assign(n, 0);
	f.assign(n, 0);
	int t = 1;
	for (int i = 0; i < n; i++) {
		if (d[i]) continue;
		dfs(i, t);
	}
	rep(i, n) {
		cout << i + 1 << " " << d[i] << " " << f[i] << endl;
	}
	return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <vector>
#include <stack>
#include <string>
#include <queue>

using namespace std;

int d[101];
int f[101];
bool isUsed[101];
int cnt = 0;

void DFS(vector< vector<int> >& G, int vertex)
{
	d[vertex] = ++cnt;
	for (int i = 0; i < G[vertex].size(); ++i)
	{
		if (G[vertex][i] == 1 && isUsed[i] == false)
		{
			isUsed[i] = true;
			DFS(G, i);
		}
	}
	f[vertex] = ++cnt;
}

void solve()
{
	int n;
	cin >> n;
	vector< vector<int> > G(n, vector<int>(n));
	for (int i = 0; i < n; ++i)
	{
		int u, k;
		cin >> u >> k;
		--u;
		for (int j = 0; j < k; ++j)
		{
			int v;
			cin >> v;
			--v;
			G[u][v] = 1;
		}
	}
	for (int i = 0; i < 101; ++i)
	{
		isUsed[i] = false;
	}
	for (int i = 0; i < n; ++i)
	{
		if (isUsed[i] == false)
		{
			isUsed[i] = true;
			DFS(G, i);
		}
	}
	for (int i = 0; i < n; ++i)
	{
		cout << i + 1 << " " << d[i] << " " << f[i] << endl;
	}
}

int main()
{
	solve();
	return(0);
}

C++: #ifdef LOCAL_BUILD
#include "pch.h"
#define DLOG(msg) cout << "#" << __LINE__ << ":" << msg << endl;
#define DLOG_V(var) \
  cout << "#" << __LINE__ << ":" << #var << " : " << var << endl;
#else
#include <bits/stdc++.h>
#define DLOG(msg)
#define DLOG_V(var)
#endif
using namespace std;

constexpr auto no_value = numeric_limits<uint64_t>::max();

struct GraphParser {
  GraphParser(vector<vector<int>>& edges_)
      : edges(edges_), start(edges.size(), 0), end(edges.size(), 0) {
  }

  void run() {
    t = 0;
    for (size_t i = 0; i < edges.size(); ++i) {
      if (!start[i]) {
        recur(i);
      }
    }
  }

  void run_stack() {
    t = 0;
    for (size_t j = 0; j < edges.size(); ++j) {
      if (start[j]) continue;
      start[j] = ++t;
      st.push(make_pair(j, 0));
      while(!st.empty()) {
        auto& p = st.top();
        auto v = p.first;
        auto& i = p.second;
        if (i < edges[v].size()) {
          auto v2 = edges[v][i++];
          if (!start[v2]) {
            start[v2] = ++t;
            st.push(make_pair(v2, 0));
          }
        } else {
          end[v] = ++t;
          st.pop();
        }
      }
    }
  }

  vector<vector<int>>& edges;
  vector<int> start;
  vector<int> end;
  stack<pair<int, size_t>> st;
  int t;

 private:
  void recur(int cur) {
    if (start[cur]) {
      return;
    }
    start[cur] = ++t;
    for (auto&& e : edges[cur]) {
      recur(e);
    }
    end[cur] = ++t;
  }
};

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

  GraphParser p(edges);
  p.run_stack();
  for (int i = 0; i < n; ++i) {
    cout << (i + 1) << " " << p.start[i] << " " << p.end[i] << endl;
  }
}