Go: package main

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

/***************************************************************
stackによる深さ優先探索を実装する。
***************************************************************/

const (
	N     = 100
	WHITE = 0
	GRAY  = 1
	BLACK = 2
)

var (
	n            int
	Adj          [N][N]int
	statusColor  [N]int
	discoverTime [N]int
	finishTime   [N]int
	clock        int
	nt           [N]int
)

/***************************************************************
Stackの定義:
- field
	container: ノードの格納されたスライス
	sp: スタックポインタ
- method
	size(): スタックに積まれているノードの個数を返す
	top(): スタックの一番上に積まれているノードを返す
	isEmpty(): スタックが空かどうかを返す
	pop(): スタックの要素をポップし削除する
	push(): スタックに要素を積む
***************************************************************/

type Stack struct {
	container []int
	sp        int
}

func (s *Stack) size() int {
	return len(s.container)
}

func (s *Stack) top() int {
	return s.container[s.sp]
}

func (s *Stack) isEmpty() bool {
	return s.sp == 0
}

func (s *Stack) pop() int {
	_pop := func() {
		s.container = s.container[:len(s.container)-1]
	}
	defer _pop()
	if s.isEmpty() {
		panic("There is no elements in stack!")
	}
	s.sp--
	return s.container[s.sp]
}

func (s *Stack) push(n int) {
	s.sp++
	s.container[s.sp] = n
}

func next(u int) int {
	for v := nt[u]; v < n; v++ {
		nt[u] = v + 1
		if Adj[u][v] == 1 {
			return v
		}
	}
	return -1
}

func _DFS(target int) {
	for i := 0; i < n; i++ {
		nt[i] = 0
	}
	stack := new(Stack)
	stack.container = make([]int, N+1)
	stack.push(target)
	statusColor[target] = GRAY
	clock++
	discoverTime[target] = clock
	for !stack.isEmpty() {
		u := stack.top()
		v := next(u)
		if v != -1 {
			if statusColor[v] == WHITE {
				statusColor[v] = GRAY
				clock++
				discoverTime[v] = clock
				stack.push(v)
			}
		} else {
			stack.pop()
			statusColor[u] = BLACK
			clock++
			finishTime[u] = clock
		}
	}
}

func DFS() {
	for i := 0; i < n; i++ {
		statusColor[i] = WHITE
		nt[i] = 0
	}
	clock = 0
	for i := 0; i < n; i++ {
		if statusColor[i] == WHITE {
			_DFS(i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, discoverTime[i], finishTime[i])
	}
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ = strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			Adj[i][j] = 0
		}
	}
	for i := 0; i < n; i++ {
		scanner.Scan()
		u, _ := strconv.Atoi(scanner.Text())
		scanner.Scan()
		k, _ := strconv.Atoi(scanner.Text())
		u--
		for j := 0; j < k; j++ {
			scanner.Scan()
			v, _ := strconv.Atoi(scanner.Text())
			v--
			Adj[u][v] = 1
		}
	}

	DFS()
}

C++: ///
// File:  alds1_11_b.cpp
// Author: ymiyamoto
//
// Created on Wed Oct 18 00:19:44 2017
//

#include <cstdint>
#include <iostream>

using namespace std;

static uint32_t n;
static uint32_t graph[100][100];
static uint32_t count = 0;
static uint32_t d[100];
static uint32_t f[100];

static void dfs(uint32_t index)
{
  count++;
  d[index] = count;
  for (uint32_t i = 0; i < n; i++) {
    if (d[i] == 0 && graph[index][i] == 1) {
      dfs(i);
    }
  }
  count++;
  f[index] = count;
}

int32_t main()
{
  cin >> n;

  for (uint32_t i = 0; i < n; i++) {
    uint32_t id, k;
    cin >> id >> k;
    for (uint32_t j = 0; j < k; j++) {
      uint32_t v;
      cin >> v;
      graph[id - 1][v - 1] = 1;
    }
  }

  dfs(0);

  for (uint32_t i = 0; i < n; i++) {
    cout << i + 1 << " " << d[i] << " " << f[i] << endl;
  }

  return 0;
}

C++: #include<iostream>
#include<stack>
using namespace std;
static const int N = 100; 
static const int WHITE = 0;
static const int GRAY = 1; 
static const int BLACK = 2;

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

int next(int u) {
	for(int v = nt[u]; v < n; v++) {
		nt[u] = v + 1;
	    if(M[u][v]) return v;
	}
	return -1;
}

void dfs_visit(int r) {
	for(int i = 0; i < n; i++) nt[i] = 0;
	
	stack<int> S;
	S.push(r);
	color[r] = BLACK;
	d[r] = ++tt;
	
	while(!S.empty()) {
		int u = S.top();
		int v = next(u);
		if(v != -1) {
			   d[v] = ++tt;
			   S.push(v);	
		} else {
			S.pop();
			color[u]  = BLACK;
			f[u] = ++tt;
		}
	}
}


void dfs() {
	for(int i = 0; i < n; i++){
		color[i] = WHITE; nt[i] = 0;
	}
	tt = 0; 
	
	for(int j = 0; j < n; j++) {
		if(color[j] == WHITE) {
			dfs_visit(j);
		}
	}
	
	for(int i =0; i < n; i++ ) {
    	cout << i+1 << " " << d[i] << " " << f[i] << endl;
	}
}


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

C++: #include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <map>
#include <unordered_map>
#include <cstring>

using namespace std;
using ll = long long;
using pint = pair<int, int>;
using Graph = vector<vector<int>>;

ll INF = 1LL << 60;

Graph G;
vector<bool> seen;
vector<int> d, f;

void dfs(Graph& G, int v, int& num) {
	seen[v] = true;
	d[v] = num++;
	for (int nv : G[v]) {
		if (seen[nv]) continue;
		dfs(G, nv, num);
	}
	f[v] = num++;
}

int main() {
	int n;
	cin >> n;
	G.resize(n);
	seen.resize(n);
	d.resize(n);
	f.resize(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].push_back(v);
		}
	}

	int num = 1;
	for (int i = 0; i < n; i++) {
		if (!seen[i]) dfs(G, i, num);
	}
	for (int i = 0; i < n; i++) {
		cout << i + 1 << " " << d[i] << " " << f[i] << endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
static const int N = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

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

int next(int u) {
  for (int v = nt[u]; v < n; v ++) {
    nt[u] = v + 1;
    if (M[u][v]) return v;
  }
  return -1;
}

void dfs_visit(int r) {
  for (int i = 0; i < n; i ++) nt[i] = 0;

  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 != -1) {
      if (color[v] == WHITE) {
        color[v] = GRAY;
        d[v] = ++tt;
        S.push(v);
      }
    } else {
      S.pop();
      color[u] = BLACK;
      f[u] = ++tt;
    }
  }
}

void dfs() {
  for (int i = 0; i < n; i ++) {
    color[i] = WHITE;
    nt[i] = 0;
  }
  tt = 0;

  for (int u = 0; u < n; u ++) {
    if (color[u] == WHITE) dfs_visit(u);
  }
  for (int i = 0; i < n; i ++) {
    cout << i+1 << " " << d[i] << " " << f[i] << endl;
  }
}

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

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

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

  dfs();

  return 0;
}