Go: package main

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

// repr state of visited node
// WHITE yet visit
// GEAY  visiting
// BLACK visited
const (
	WHITE int = iota
	GRAY
	BLACK
)

type dfsGraph struct {
	g      [][]int
	colors []int
	stime  []int // Start time of visiting node
	ftime  []int // Finish time of visiting node
}

var time int

func makeAdjList() [][]int {
	var n int
	fmt.Scanf("%d", &n)

	adj := make([][]int, n)
	for i := 0; i < n; i++ {
		adj[i] = make([]int, n)
	}

	sc := bufio.NewScanner(os.Stdin)
	for i := 0; i < n; i++ {
		sc.Scan()
		nodeInfo := strings.Split(sc.Text(), " ")
		outDegree, _ := strconv.Atoi(nodeInfo[1])

		if outDegree > 0 {
			for k := 0; k < outDegree; k++ {
				j, _ := strconv.Atoi(nodeInfo[k+2])
				j-- // convert 1 based to 0 based
				adj[i][j] = 1
			}
		}
	}

	return adj
}

func (dg dfsGraph) dfsVisit(u int) {
	// 頂点uを訪問中に設定
	dg.colors[u] = GRAY
	time++
	dg.stime[u] = time

	// uの隣接nodeを訪問
	for v := 0; v < len(dg.g); v++ {
		if dg.g[u][v] == 0 {
			continue // 辺がなければスキップ
		}

		// vが未訪問なら訪問
		if dg.colors[v] == WHITE {
			dg.dfsVisit(v)
		}
	}

	// 頂点uを訪問済みに設定
	dg.colors[u] = BLACK
	time++
	dg.ftime[u] = time
}

func (dg dfsGraph) dfs() {
	for i := 0; i < len(dg.g); i++ {
		if dg.colors[i] == WHITE {
			dg.dfsVisit(i)
		}
	}
}

func (dg dfsGraph) printDfsTime() {
	for i := 0; i < len(dg.g); i++ {
		fmt.Printf("%d %d %d\n", i+1, dg.stime[i], dg.ftime[i])
	}
}

func main() {
	adj := makeAdjList()
	colors := make([]int, len(adj))
	stime := make([]int, len(adj))
	ftime := make([]int, len(adj))
	graph := dfsGraph{adj, colors, stime, ftime}
	graph.dfs()
	graph.printDfsTime()
}

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

int n, G[101][101], S[101], T[101];

int dfs(int p, int s) {
    if (S[p] != 0) return 0;
    S[p] = s;
    s++;
    for (int i = 0; i < n; i++) {
        if (G[p][i] == 1) {
            s = max(s, dfs(i, s) + 1);
        }
    }
    T[p] = s;
    return s;
}


int main(void) {
    int u, k, v, s;
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            cin >> v;
            G[u - 1][v - 1] = 1;
        }
    }

    s = 0;
    for (int i = 0; i < n; i++)
        if (S[i] == 0) s = dfs(i, s);

    for (int i = 0; i < n; i++)
        printf("%d %d %d\n", i + 1, S[i], T[i]);

    return 0;
}

C++: #include<iostream>
#include<string>
#include<algorithm>
#include<utility>
#include<vector>
#include<map>
#include<set>
#include<tuple>
#include<stack>
#include<queue>
#include<functional>
#include<iterator>
#include<cmath>

using namespace std;

typedef pair<int,int> P;

vector<int> g[100];
int ans[100][2]; //[i][0] 到着　　[i][1] 終了
int t=1;

void dfs(int v){
	ans[v][0] = t;
	t++;
	for(int i=0;i<g[v].size();i++){
		dfs(g[v][i]);
		t++;
	}
	ans[v][1] = t;

	return;
}

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

	int n;
	cin >> n;
	
	for(int i=0;i<n;i++){
		int u, nume;
		cin >> u >> nume;

		int v;
		for(int j=0;j<nume;j++){ //jは回数数えるだけ
			cin >> v;
			g[u-1].push_back(v-1);
		}
	}

//	for(int i=0;i<n;i++){
//		for(int j=0;j<g[i].size();j++){
//			cout << g[i][j] + 1 << " ";
//		}
//		cout << "\n";
//	}

	dfs(0);
	
	for(int i=0;i<n;i++){
		cout << i+1 << " " << ans[i][0] << " " << ans[i][1] << "\n";
	}

	return 0;
}

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

vector<vector<int>> graph;
vector<pair<int, int>> timestamp;
int time__=0;

void dfs(int v){
  if (timestamp[v].first == 0)
    timestamp[v].first = ++time__;
  else
    return;
  for (int i=0;i<graph[v].size();++i){
    dfs(graph[v][i]);
  }
  timestamp[v].second = ++time__;
}

int main(){
  int n;
  cin >> n;
  graph.resize(n+1); timestamp.resize(n+1);
  for (int i=0;i<n;++i){
    int id,k;
    cin >> id >> k;
    for(int j=0;j<k;++j){
      int temp;
      cin >> temp;
      graph[i].push_back(temp-1);
    }
  }

  for (int i=0;i<n;i++)
    dfs(i);

  for (int i=0;i<n;i++){
    cout << i+1 << " " <<timestamp[i].first << " " << timestamp[i].second << endl;
  }

  return 0;
}

C++: #include <vector>
#include <iostream>
using namespace std;
int n, u, k, v, t, d[100][2]; vector<int> g[100];
void rec(int pos) {
	d[pos][0] = ++t;
	for(int i = 0; i < g[pos].size(); i++) {
		if(!d[g[pos][i]][0]) rec(g[pos][i]);
	}
	d[pos][1] = ++t;
}
int main() {
	cin >> n;
	for(int i = 0; i < n; i++) {
		cin >> u >> k;
		for(int j = 0; j < k; j++) cin >> v, g[u - 1].push_back(v - 1);
	}
	rec(0);
	for(int i = 0; i < n; i++) cout << i + 1 << ' ' << d[i][0] << ' ' << d[i][1] << endl;
}

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

using namespace std;

int n;
int V[105][105];
vector<int> d(105, 0), f(105, 0);
int t = 0;

void dfs(int x) {
	bool p = false;
	if (d[x] != 0) p = true;
	if (d[x] == 0) {
		t++;
		d[x] = t;
	}
	for (int j = 1; j <= n; j++) {
		if (V[x - 1][j - 1] == 1 && d[j] == 0) {
			dfs(j);
		}
	}
	t++;
	if (p) t--;
	if (f[x] == 0) f[x] = t;
}


int main() {
	cin >> n;
	for (int i = 0; i<n; i++) {
		for (int j = 0; j<n; j++) {
			V[i][j] = 0;
		}
	}
	for (int i = 0; i<n; i++) {
		int p, m;
		cin >> p >> m;
		for (int j = 0; j<m; j++) {
			int q;
			cin >> q;
			V[p - 1][q - 1] = 1;
		}
	}
	for (int i = 0; i<n; i++) {
		dfs(i + 1);
	}
	for (int i = 0; i<n; i++) {
		cout << i + 1 << " " << d[i + 1] << " " << f[i + 1] << endl;
	}
}

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

ll N = 100;
vector<ll> ans1;
vector<ll> ans2;
vector<bool> seen;
ll C = 0;

ll gcd(ll a, ll b) { return b?gcd(b,a%b):a;}
ll lcm(ll a, ll b) { return b/gcd(a,b)*b;}


void dfs(vector< vector<ll> > &G, int v) {
  seen[v] = true;
  // v から行ける各頂点 next_v について
  for (auto next_v : G[v]) {
    if (seen[next_v]) continue; // next_v が探索済だったらスルー
    ans1[next_v] = ++C;
    //printf("ans1[%d] = %d\n", next_v+1, C);
    dfs(G, next_v); // 再帰的に探索
    ans2[next_v] = ++C;
    //printf("ans2[%d] = %d\n", next_v+1, C);
  }
}

int main() {
  cin >> N;
  vector< vector<ll> > G(N);
  G.resize(N);
  seen.resize(N, false);
  ans1.resize(N, 0);
  ans2.resize(N, 0);
  int k;
  int tmp;
  rep(i, N) {
    cin >> tmp >> k;
    rep(j, k) {
      int tmp;
      cin >> tmp;
      G[i].push_back(tmp-1);
    }
  }

  rep(i, N) {
    if (!seen[i]) {
      ans1[i] = ++C;
      dfs(G, i);
      ans2[i] = ++C;
    }
  }
  rep(i, N) {
    cout << i+1 << " " << ans1[i] << " " << ans2[i] << endl;
  }
  return 0;
}

C++: #include <iostream>
using namespace std;
struct Node{
  int u;
  int k;
  int v[99];

  int start;
  int finish;
};

int deep(Node nod[],int x,int count){
  if(nod[x].start)
    return count;

  nod[x].start=(++count);
  for(int i=0; i<nod[x].k; i++)
    count = deep(nod,nod[x].v[i]-1,count);

  nod[x].finish= (++count);
  return count;
}

int main(){
  int n,count=0;
  Node nod[100];

  cin >> n;
  for(int i=0; i<n; i++){
    cin >> nod[i].u >> nod[i].k;
    
    for(int j=0; j<nod[i].k; j++)
      cin >> nod[i].v[j];
    
    nod[i].start=0;
    nod[i].finish=0;
  }

  for(int i=0; i<n; i++)
    count = deep(nod,i,count);
  
  for(int i=0; i<n; i++){
    cout << nod[i].u << " " << nod[i].start << " " << nod[i].finish << endl;
  }
}