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++: #include <stdio.h>
#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;

// 再帰関数による深さ優先探索
void dfs_visit(int u)
{
  int v;
  color[u] = GRAY;
  d[u] = ++tt; // 最初の訪問
  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;
  // 初期化
  for (u = 0; u < n; u++)
    color[u] = WHITE;
  tt = 0;

  for (u = 0; u < n; u++)
  {
    // 未訪問のuを始点として深さ優先探索
    if (color[u] == WHITE)
      dfs_visit(u);
  }
  for (u = 0; u < n; u++)
  {
    printf("%d %d %d\n", u + 1, d[u], f[u]);
  }
}

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

  scanf("%d", &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++)
  {
    scanf("%d %d", &u, &k);
    u--;
    for (j = 0; j < k; j++)
    {
      scanf("%d", &v);
      v--;
      M[u][v] = 1;
    }
  }
  dfs();

  return 0;
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <queue>
#include <stack>
#include <map>
#define FOR(i,b,e) for(int i=b;i<e;i++)
#define REP(i,n) FOR(i,0,n)
using namespace std;

const int N = 100;
int n;
int d[N+1], f[N+1], state[N+1], ns[N+1][N+1];
stack<int> s;

int next(int u) {
  FOR(i, 1, n+1) {
    if (ns[u][i] == 1 && state[i] == 0) return i;
  }
  return -1;
}
int main() {
	cin.tie(0);
 	ios::sync_with_stdio(false);

  cin >> n;

  FOR(i, 1, n+1) state[i] = 0;
  FOR(i, 1, n+1) {
    FOR(j, 1, n+1) {
      ns[i][j] = 0;
    }
  }

  REP(i, n) {
    int p, m;
    cin >> p; cin >> m;

    REP(j, m) {
      int pp; cin >> pp;
      ns[p][pp] = 1;
    }
  }

  int t = 1;

  s.push(1);
  state[1] = 1;
  d[1] = 1;
  while (!s.empty()) {
    t++;

    int p, np;
    p = s.top();
    if ((np = next(p)) != -1) {
      s.push(np);
      state[np] = 1;
      d[np] = t;
    } else {
      s.pop();
      state[p] = 2;
      f[p] = t;
    }
  }

  FOR(i, 1, n+1) {
    cout << i << " " << d[i] << " " << f[i] << endl;
  }
}

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

#define N 101

void DepthFirstSearch();

class stack{
public:
    int array[100];
    int top = -1;
    
    void push(int v) {
        top++;
        array[top] = v;
        return;
    }
    
    int pop() {
        top--;
        return array[top+1];
    }
    
    int show() {
        return array[top];
    }
};

typedef struct {
    int d;
    int f;
} P;

int n;
int t = 0;
int a[N][N] = {};
stack s;
P list[N];

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    cin>>n;
    
    int u, k, v;
    for(int i = 0; i < n; i++) {
        cin>>u>>k;
        
        for(int j = 0; j < k; j++) {
            cin>>v;
            a[u][v] = 1;
        }
    }
    
    for(int i = 1; i <= n; i++) {
        if(list[i].d == 0) {
            s.push(i);
            for(int j = 1; j <= n; j++) a[j][i] = 0;
            DepthFirstSearch();
            s.pop();
        }
    }
    
    for(int i = 1; i <= n; i++) {
        cout<<i<<' '<<list[i].d<<' '<<list[i].f<<endl;
    }
    
    return 0;
}

void DepthFirstSearch() {
    t++;
    int u = s.show();
    list[u].d = t;
    for(int i = 1; i <= n; i++) {
        if( a[u][i] == 1 ) {
            s.push(i);
            a[u][i] = 0;
            for(int j = 1; j <= n; j++) a[j][i] = 0;
            DepthFirstSearch();
            s.pop();
        }
    }
    t++;
    list[u].f = t;
}

C++: #include<bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vs = vector<string>;
using msi = map<string, int>;
using mii = map<int, int>;
using psi = pair<string, int>;
using pii = pair<int, int>;
using vlai = valarray<int>;
#define rep(i,n) for(int i=0;i<n;i++)
#define range(i,s,n) for(int i=s;i<n;i++)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define fs first
#define sc second
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define INF 1E9
#define EPS 1E-9
#define MOD (ll)(1E9+7)
#define PI 3.1415926535897932384

template <class T>ostream &operator<<(std::ostream &o, const vector<T> &v)
{
	rep(i, v.size()) {
		o << (i > 0 ? " " : "") << v[i];
	}
	return o;
}
int n,t=0;
vvi a;
vi d;
vi f;

void Depth(int pos) {
	if (d[pos] == 0) {
		d[pos] = ++t;
	}
	rep(i, n) {
		if (a[pos][i] == 1) {
			Depth(i);
		}
	}
	if (f[pos] == 0) {
		f[pos] = ++t;
	}
}


int main() {
	cin >> n;
	a.resize(n, vi(n, 0));
	d.resize(n, 0);
	f.resize(n, 0);
	rep(i, n) {
		int num,m;
		cin >>num >>m;
		rep(i, m) {
			int tmp;
			cin >> tmp;
			a[num - 1][tmp - 1] = 1;
		}
	}
	Depth(0);
	rep(i, n) {
		cout << i + 1 << " " << d[i] << " " << f[i] << endl;
	}
}