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++: // -*- mode:c++; coding:utf-8; c-basic-offset:2; -*-
// ALDS1_11_B: Depth First Search

#include <algorithm>
#include <cstdio>
#include <stack>
#include <utility>

using uint = unsigned int;

class Graph {
  const uint n_;
  uint* const g_;
  std::pair<uint, uint>* const visited_;
  uint time_;
  
public:
  Graph(uint n) : n_(n),
                  g_(new uint[(n_*n_)]),
                  visited_(new std::pair<uint, uint>[n_])
  {
    std::fill(g_, g_+(n_*n_), 0u);
  }

  ~Graph()
  {
    delete[] g_;
    delete[] visited_;
  }
  
  uint* operator [](uint i) const { return g_+(n_*i); }

  std::pair<uint, uint>* visited() const { return visited_; }

  void dfs()
  {
    init_visited();
    for (auto i = 0u; i < n_; ++i) {
      inner_dfs(i);
    }
  }

private:
  void init_visited()
  {
    time_ = 0u;
    for (auto i = 0u; i < n_; ++i) {
      visited_[i].first = 0u;
    }
  }

  void inner_dfs(uint i)
  {
    if (visited_[i].first) {
      return;
    }
    visited_[i].first = time_++;
    for (auto j = 0u; j < n_; ++j) {
      auto k = (*this)[i][j];
      if (k) {
        inner_dfs(j);
      }
    }
    visited_[i].second = time_++;
  }
};

int main()
{
  uint n;
  std::scanf("%u", &n);

  Graph g(n);

  uint u, k, v;
  for (auto i = 0u; i < n; ++i) {
    std::scanf("%u %u", &u, &k);
    for (auto j = 0u; j < k; ++j) {
      std::scanf("%u", &v);
      g[u-1][v-1] = 1;
    }
  }

  g.dfs();
  auto visited = g.visited();
  for (auto i = 0u; i < n; ++i) {
    std::printf("%u %u %u\n", i+1, visited[i].first+1, visited[i].second+1);
  }
}

// eof

C++: #include <iostream>
#include <string>
#include <vector>
using namespace std;
typedef long long ll;
const int INF = 1<<30; 
const int MOD = 1e9 + 7;
const int MAX_N = 150;
int G[MAX_N][MAX_N], found[MAX_N], finished[MAX_N];
int Time, N;
void dfs(int u)
{
    Time++;
    found[u] = Time;
    for(int nextV = 1; nextV <= N; nextV++)
    {
        if(found[nextV] || G[u][nextV] == 0) continue;
        dfs(nextV);
    }
    Time++;
    finished[u] = Time;
}
void init()
{
    Time = 0;
    for(int i = 0; i <= N; i++)
    {
        found[i] = 0;
        finished[i] = 0;
    }
    for(int i = 0; i <= N; i++) for(int j = 0; j <= N; j++) G[i][j] = 0;
}
int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    cin >> N;
    init();
    for(int i = 0; i < N; i++)
    {
        int u, k; cin >> u >> k;
        for(int j = 0; j < k; j++)
        {
            int v; cin >> v;
            G[u][v] = 1;
        }
    }
    int u = 1;
    while(u <= N)
    {
        if(found[u] == 0) dfs(u);
        u++;
    }
    for(int v = 1; v <= N; v++)
    {
        cout << v << " " << found[v] << " " << finished[v] << endl;
    }
    return 0;
}

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

void solve(){
  int n; cin >> n;
  vector<vector<int> > v(n + 1, vector<int>(n + 1, 0));
  for(int i = 0; i < n; i++){
    int u, k; cin >> u >> k;
    for(int j = 0; j < k; j++){
      int x; cin >> x;
      v[u][x] = 1;
    }
  }
  vector<int> d(n + 1), f(n + 1), c(n + 1, 0);
  stack<int> s;
  int t = 0;
  for(int j = 1; j <= n; j++){
    if(c[j] == 0){
      s.push(j);
      d[j] = ++t;
      c[j] = 1;
      while(s.size() != 0){
        t++;
        int x = s.top();
        int i;
        for(i = 1; i <= n; i++){
          if(v[x][i] == 1 && c[i] == 0){
            d[i] = t;
            c[i] = 1;
            s.push(i);
            break;
          }
        }
        if(i == n + 1){
          f[x] = t;
          s.pop();
        }
      }
    }
  }
  for(int i = 1; i <= n; i++){
    cout << i << " " << d[i] << " " << f[i] << endl;
  }
  return;
}

int main(){
  solve();
  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 n,m[N][N];
int color[N],sta[N],fin[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; //下に辺があれば返す
  }
  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;
  sta[r]= ++tt;

  while(!s.empty()) //空じゃない間
  {
    int u=s.top();
    int v= next(u);
    if(v != -1)
    {
      if(color[v]==white)
      {
        color[v]=gray;
        sta[v]= ++tt;
        s.push(v);
      }
    }
    else //v=-1
    {
      s.pop();
      color[u]=black;
      fin[u]= ++tt;
    }
  }
}

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

  //未訪問のuを始点としてdfsする
  for(int u=0;u<n;u++)
  {
    if(color[u]==white) dfs_visit(u);
  }
  for(int i=0;i<n;i++)
  {
    cout<<i+1<<" "<<sta[i]<<" "<<fin[i]<<endl;
  }
}

int main()
{
  //入力
  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; //辺があれば1と定義される
    }
  }

  dfs();
}