Go: package main

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

var N int
var A [][]int
var t int
var color, d, f []int

const (
	WHITE = iota
	GRAY
	BLACK
)

func dfsVisit(u int) {
	color[u] = GRAY
	t ++
	d[u] = t
	for v:=0; v<N; v++ {
		if A[u][v] == 0 {
			continue
		}
		if color[v] == WHITE {
			dfsVisit(v)
		}
	}
	color[u] = BLACK
	t++
	f[u] = t
}

func dfs() {
	for u:=0; u<N; u++ {
		if color[u] == WHITE {
			dfsVisit(u)
		}
	}
	for u:=0; u<N; u++{
		fmt.Printf("%d %d %d\n", u+1, d[u], f[u])
	}
}


func nextInt(scanner *bufio.Scanner) int {
	scanner.Scan()
	num, _ := strconv.Atoi(scanner.Text())
	return num
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	N = nextInt(scanner)
	color = make([]int, N)
	d = make([]int, N)
	f = make([]int, N)
	A = make([][]int, N)
	for i:=0; i<N; i++{
		A[i] = make([]int, N)
	}
	for i:=0; i<N; i++{
		index := nextInt(scanner) - 1
		cnt := nextInt(scanner)
		for j:=0; j<cnt; j++ {
			v := nextInt(scanner) - 1
			A[index][v] = 1
		}
	}
	dfs()
}

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

using namespace std;

static const int N = 100;
static const int YET = 0;
static const int ALREADY = 1;

int state[N];
int timeTable[N][2];
int timeCount = 0;
int currentV;
stack<int> st;
int M[N][N];

void travel() {
  while(!st.empty()) {
    currentV = st.top();
    st.pop();

    if(state[currentV] == YET) {
      timeCount++;
      timeTable[currentV][0] = timeCount;
      state[currentV] = ALREADY;
      st.push(currentV);

      for(int i = N; i > -1; i--) {
        if(M[currentV][i] == 1 && state[i] == YET) {
          st.push(i);
        }
      }
    }
    else if(timeTable[currentV][1] == 0){
      timeCount++;
      timeTable[currentV][1] = timeCount;
    }
  }
}
int main(void) {


  int n, u, k, v;

  cin >> n;

  //?????????
  for(int i = 0; i < n; i++) {
    for(int j = 0; j < n; j++) {
      M[i][j] = 0;
    }
  }

  //Graph -> Matrix
  for(int i = 0; i < n; i++) {
    cin >> u >> k;
    u--;//0-origian
    for(int j = 0; j < k; j++) {
      cin >> v;
      v--;
      M[u][v] = 1;
    } 
  }

  st.push(0);
  travel();
  for(int i = 0; i < N; i++) {
    if(state[i] == YET) {
      st.push(i);
      travel();
    }
  }


  for(int i = 0; i < n; i++) {
    cout << i + 1 << " " << timeTable[i][0] << " " << timeTable[i][1] << endl;
  }
  return 0;
}

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

static const int MAX_NUM = 100;

void dsf_cal(int matrix[][MAX_NUM + 1], int state[], int time[][2], int index, int num)
{
    static int t = 0;
    stack<int> S;

    S.push(index);
    state[index]   = 1;
    time[index][0] = t;
    ++t;

    while (S.empty() != true) {
        int i;
        int target = S.top();
        for (i = 0; i < num; i++) {
            if (state[i] == 0) {
                S.push(i);
                state[i]   = 1;
                time[i][0] = t;
                ++t;
                break;
            }
        }
        if (i == num) {
            time[target][1] = t;
            ++t;
            S.pop();
        }
    }

    return;
}

void DSF(int matrix[][MAX_NUM + 1], int num)
{
    int state[MAX_NUM]   = {0};
    int time[MAX_NUM][2] = {0};

    for (int i = 0; i < num; i++) {
        if (state[i] == 0) {
            dsf_cal(matrix, state, time, i, num);
        }
    }

    for (int i = 0; i < num; i++) {
        printf("%d %d %d\n", i, time[i][0], time[i][1]);
    }

    return;
}

int main(void)
{
    int num;
    int index, elemNum;
    int matrix[MAX_NUM + 1][MAX_NUM + 1] = {0};

    scanf("%d", &num);
    for (int i = 0; i < num; i++) {
        scanf("%d %d", &index, &elemNum);
        for (int j = 0; j < elemNum; j++) {
            scanf("%d", matrix[i+1][j]);
        }
    }

    DSF(matrix, num);

    return 0;
}

C++: #include <iostream>
#include<string>
#include<cmath>
#include<algorithm>
#include<cctype>
#include<queue>
#include<stack>
#include<stdio.h>
#include<vector>
#include<set>
#include<map>
#include<array>
#include<iomanip>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
int ms[100][100],n,tt=0;
int color[101],nt[101];
int d[100],f[100];
int next(int v){
    for(int i=nt[v];i<n;i++){
        nt[v]=i+1;
        if(ms[v][i]==1)return i;
    }
    return -1;
}

void visit_dfs(int v){
    stack<int> s;
    s.push(v);
    d[v]=++tt;
    color[v]=1;
    while(!s.empty()){
        int u=s.top();
        int uu=next(u);
        if(uu!=-1){
            if(color[uu]==0){
            s.push(uu);
            d[uu]=++tt;
            color[uu]=1;
            }
        }else{
            s.pop();
            f[u]=++tt;
            color[u]=2;
        }
    }
    
    
}
void dfs(){
    for(int i=0;i<n;i++){
        color[i]=0;
        nt[i]=0;
    }
    for(int i=0;i<n;i++){
        if(color[i]==0){
            visit_dfs(i);
        }
    }
    for(int i=0;i<n;i++){
        cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
    }
}

int main(){
    
    cin>>n;
    rep(i,n){
        int a,b,c;
        cin>>a>>b;
        a--;
        rep(j,b){
            cin>>c;
            c--;
            ms[a][c]=1;
        }
    }
    
    dfs();
    return 0;

    
}

C++: #include <iostream>
#include <stack>
#define N 100
#define WHITE 0
#define GRAY  1
#define BLACK 2
#define NIL -1

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

// uの隣接点を番号順に取得する
// nt[N]には番号順での探索開始位置を保存する
// 隣接点がなければ-1を返す
int next(int u)
{
	for (int v = nt[u]; v < n; v++)
	{
		nt[u]++;
		if (M[u][v]) return v;
	}
	return NIL;
}

// rを開始地点として深さ優先探索を行う
void dfs_visit(int r)
{
	std::stack<int> S;
	S.push(r);
	color[r] = GRAY;
	d[r] = tt++;

	while (!S.empty())
	{
		int u = S.top();
		int v = next(u);
		if (v != NIL)
		{
			if (color[v] == WHITE)
			{
				S.push(v);
				color[v] = GRAY;
				d[v] = tt++;
			}
		}
		else
		{
			S.pop();
			color[u] = BLACK;
			f[u] = tt++;
		}
	}
}

//初期化処理、探索、結果出力を行う
void dfs()
{
	for (int i = 0; i < n; i++)
	{
		color[i] = WHITE;
		nt[i] = 0;
	}
	tt = 1;

	for (int i = 0; i < n; i++)
	{
		if (color[i] == WHITE) dfs_visit(i);
	}

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

int main()
{
	std::cin >> n;
	for (int i = 0; i < n; i++)
	{
		for (int j = 0; j < n; j++)
		{
			M[i][j] = 0;
		}
	}

	int u, k, v;
	for (int i = 0; i < n; i++)
	{
		std::cin >> u >> k;
		u--;
		for (int j = 0; j < k; j++)
		{
			std::cin >> v;
			v--;
			M[u][v] = 1;
		}
	}

	dfs();
}

C++: #include <iostream>
#include <stack>
using namespace std;
const int MAX_N = 100;

int A[MAX_N+1][MAX_N+1];
pair<int, int> TIMESTAMPS[MAX_N+1];
int N;

void solve() {
  int ts = 0;
  stack<int> S;

  for (int i = N; i > 0; i--) {
    if (TIMESTAMPS[i].first == 0) S.push(i);
  }

  while (!S.empty()) {
    int c = S.top();

    if (TIMESTAMPS[c].first == 0)
      TIMESTAMPS[c].first = ++ts;

    for (int i = N; i > 0; i--) {
      if (A[c][i] == 1 && TIMESTAMPS[i].second == 0)
        S.push(i);
    }

    if (S.top() == c) {
      if (TIMESTAMPS[c].second == 0)
        TIMESTAMPS[c].second = ++ts;
      S.pop();
    }
  }
}

int main() {
  cin >> N;

  for (int i = 1; i <= N; i++) {
    for (int j = 1; j <= N; j++) {
      A[i][j] = 0;

    }
    TIMESTAMPS[i] = make_pair(0, 0);
  }

  for (int i = 0; i < N; i++) {
    int u, k; cin >> u >> k;
    for (int j = 0; j < k; j++) {
      int t; cin >> t;
      A[u][t] = 1;
    }
  }

  solve();

  for (int i = 1; i <= N; i++) {
    cout << i << ' '
         << TIMESTAMPS[i].first << ' '
         << TIMESTAMPS[i].second << endl;
  }

  return 0;
}