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++: //aizu
#include <iostream>
#include <vector>
#include <bitset>
#include <algorithm>
using namespace std;

vector <int> v[101];

pair <int, int> af[101];

bitset <101> viz;

int cnt;

void DFS(int nod)
{
    cnt++;
    af[nod].first = cnt;
    viz[nod] = 1;

    for (size_t i = 0; i < v[nod].size(); ++i)
    {
        if (viz[v[nod][i]] == 0)
            DFS(v[nod][i]);
    }
    cnt++;
    af[nod].second = cnt;
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);

    int n, u, k, ind;
    cin >> n;
    for (int i = 1; i <= n; ++i)
    {
        cin >> u >> k;
        for (int j = 1; j <= k; ++j)
        {
            cin >> ind;
            v[u].push_back(ind);
        }
        sort(v[u].begin(), v[u].end());
    }

    for (int i = 1; i <= n; ++i)
        if (viz[i] == 0)
            DFS(i);

    for (int i = 1; i <= n; ++i)
        cout << i << " " << af[i].first << " " << af[i].second << "\n";
    return 0;
}

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

int N;
int a[110][110]={{0}};
int d[110][5]={{0}};
int T=1;

void dfs(int cur);

int main(){
        cin >> N;
        for(int i=0; i<N; i++){
                int v,n;
                cin >> v;
                cin >> n;
                for(int j=0; j<n; j++){
                        int V;
                        cin >> V;
                        a[v-1][V-1]=1;
                }
        }
        for(int i=0; i<N; i++){
                if(!d[i][0])dfs(i+1);
        }
        for(int i=0; i<N; i++){
                cout << i+1 << " ";
                for(int j=0; j<2; j++){
                        cout << d[i][j];
                        if(!j)cout << " ";
                }
        cout << endl;
        }
}


void dfs(int cur){
        d[cur-1][0]=T;
        T++;
        //cerr << "visiting_" << cur << " " << T << endl;
        for(int i=0; i<N; i++){
                if(a[cur-1][i] && !d[i][0])dfs(i+1);
        }
        d[cur-1][1]=T;
        T++;
        if(cur>1)cur--;
}

C++: #include <bits/stdc++.h>
#define ALL(a)  (a).begin(),(a).end()
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
using namespace std;
typedef long long ll;
typedef pair<int, int> P;
typedef pair<long long, long long> Pll;
typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<long long> vll;
typedef vector<vector<long long>> vvll;
template <typename T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template <typename T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

vvll edge(110, vll(0));
vll d(110, -1), f(110, -1);

void dfs(int n, int &time){
  if(edge.at(n).size() == 0){
    d.at(n) = time;
    time++;
    f.at(n) = time; time++;
    return;
  }
  d.at(n) = time; time++;
  bool flag = true;
  for(int i = 0; i < edge.at(n).size(); i++){
    if(d.at(edge.at(n).at(i)) == -1){
      dfs(edge.at(n).at(i), time);
    }
  }
  f.at(n) = time; time++;
}

int main(){
  int n;
  cin >> n;
  
  for(int i = 0; i < n; i++){
    int u, k;
    cin >> u >> k;
    u--;
    for(int j = 0; j < k; j++){
      ll v;
      cin >> v;
      v--;
      edge.at(u).push_back(v);
    }
  }
  int time = 1;
  for(int i = 0; i < n; i++){
    if(d.at(i) == -1) dfs(i, time);
  }
  
  for(int i = 0; i < n; i++){
    cout << i+1 << ' ' << d.at(i) << ' ' << f.at(i) << endl;
  }

}

C++: #include<cstdio>
#include<iostream>
#include<stack>
#include<vector>
#include<algorithm>
#include<cstring>
#include<cstdlib>
#define _USE_MATH_DEFINES // M_PI????????????????????????
#include<math.h>
#pragma warning(disable:4996)
using namespace std;

#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++){ // ????¨???????u????§??????¨????????±???????????¢?´¢
		if( color[u]==WHITE ) dfs_visit(u);
	}
	for(u=0; u<n; u++){
		cout << u+1 << d[u] << f[u] << "\n";
	}
}

int main(){
	int u, v, k, i, j;
	cin >> n;

	for(i=0; i<n; i++){
		cin >> u >> k;
		u--;
		for(j=0; j<k; j++){
			cin >> v;
			v--;
			M[u][v] = 1;
		}
	}
	dfs();
	return 0;
}

C++: #include<stdio.h>
#define N 100

const int WHITE = 0;
const int GRAY = 1;
const int BLACK = 2;

void dfs_visit(int);
void dfs();

static int n, M[N][N], color[N], d[N], f[N], tt;;

int main(){
  int u, k, v, 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++){
    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;
}

void dfs_visit(int u){
  int v;
  color[u] = GRAY;
  tt++;
  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 i, u;
  for (i = 0; i < n; i++){
      color[i] = WHITE;
  }
  tt = 0;
  for (u = 0; u < n; u++){
    if (color[u] == WHITE){
        dfs_visit(u);
    }
  }
  for (i = 0; i < n; i++){
    printf("%d %d %d\n", i+1, d[i], f[i]);
  }
}