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<algorithm>
#include<iostream>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<vector>
#include<queue>
#include<stack>
#include<cmath>
#include<list>
#include<map>
#include<set>
using namespace std;

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef stack<int> SI;
typedef pair<int,int> PII;
typedef long long LL;

#define d(x)  cout<<#x<<" = "<<(x)<<endl;
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define REACH(i,c) for(typeof((c).rbegin()) i=(c).rbegin(); i!=(c).rend(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c,n) sort(c,c+n)
#define VSORT(c) sort((c).begin(),(c).end())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define DFOR(i,b,a) for(int i=(b)-1;i>=(a);--i)
#define DREP(i,n) DFOR(i,n,0)
#define INF 2000000000

const double EPS = 1e-10;
const double PI  = acos(-1.0);
////////////////////////////////////////////////
//?????????????????????????????????
SI s;//?¨?????????????????????????
int n;//??????????????°
int t;//??????
int d[101];//??????????????????????¨????????????????????????????????????????
int f[101];//??????????????£??\?????????????????????????????????????????????????????????
int a[101][101];//??£??\?????????
int p[101];//??£??\?????????????¨???????????????????????????????
int flag;//???
int main()
{
	cin>>n;
	FOR(i,1,n+1)//??£??\??????????????????
	{
		int k,m;cin>>k>>m;
		a[k][0]=m;
		FOR(j,1,m+1)
		{
			int x;cin>>x;
			a[k][j]=x;
		}
	}
	d[1]=1;
	FOR(i,1,101)p[i]=1;//??£??\??????????????????????????????????????????1???????????????
	for(s.push(1),t=2;;t++)
	{
		//s.top()?????????????????????????????????
		if(a[s.top()][0]==0)
		{
			f[s.top()]=t;
			s.pop();
		}
		else
		{
			int next=a[s.top()][p[s.top()]];
			for(;d[next]!=0;)
			{
				p[s.top()]++;
				if(p[s.top()]>a[s.top()][0])
				{
					f[s.top()]=t;
					s.pop();
					flag=1;
					break;
				}
				next=a[s.top()][p[s.top()]];
			}
			if(flag==0)
			{
				s.push(next);
				d[s.top()]=t;
			}
		}
		flag=0;
		if(f[1]!=0)break;
	}
	FOR(i,1,n+1)cout<<i<<" "<<d[i]<<" "<<f[i]<<endl;
	return 0;
}

C++: #include <bits/stdc++.h>
#define _GLIBCXX_DEBUG
using namespace std;
using ll = long long;
using vec = vector<ll>;
using vect = vector<double>;
using Graph = vector<vector<ll>>;
#define loop(i, n) for (ll i = 0; i < n; i++)
#define Loop(i, m, n) for (ll i = m; i < n; i++)
#define pool(i, n) for (ll i = n; i >= 0; i--)
#define Pool(i, m, n) for (ll i = n; i >= m; i--)
#define mod 1000000007ll;
#define setbit bitset<8>
#define flagcount __builtin_popcount
#define flag(x) (1 << x)
#define flagadd(bit, x) bit |= flag(x)
#define flagpop(bit, x) bit &= ~flag(x)
#define flagon(bit, i) bit &flag(i)
#define flagoff(bit, i) !(bit & (1 << i))
#define all(v) v.begin(), v.end()
#define low2way(v, x) lower_bound(all(v), x)
#define high2way(v, x) upper_bound(all(v), x)
#define count2way(v, x) high2way(v, x) - low2way(v, x)
#define lower(v, x) low2way(v, x) - v.begin()       //1番左が0、もし見つから無いならｎを出力
#define higher(v, x) high2way(v, x) - v.begin() - 1 //1番左が0、もし見つからないならn-1を出力（注意）
#define putout(a) cout << a << endl
#define putout2(a, b) \
  putout(a);          \
  putout(b)
#define putout3(a, b, c) \
  putout(a);             \
  putout(b);             \
  putout(c)
#define putout4(a, b, c, d) \
  putout(a);                \
  putout(b);                \
  putout(c);                \
  putout(d)
#define putout5(a, b, c, d, e) \
  putout(a);                   \
  putout(b);                   \
  putout(c);                   \
  putout(d);                   \
  putout(e)
#define Gput(a, b) G[a].push_back(b)
#define cin1(a) cin >> a
#define cin2(a, b) cin >> a >> b
#define cin3(a, b, c) cin >> a >> b >> c
#define cin4(a, b, c, d) cin >> a >> b >> c >> d
#define cin5(a, b, c, d, e) cin >> a >> b >> c >> d >> e
#define sum(v) accumulate(all(v), 0ll)
#define gcd(x, y) __gcd(x, y)
ll ctoi(char c)
{
  if (c >= '0' && c <= '9')
  {
    return c - '0';
  }
  return 0;
}
ll lcm(ll x, ll y)
{
  ll z = gcd(x, y);
  return x * y / z;
}

ll primejudge(ll n)
{
  if (n < 2)
    return 0;
  else if (n == 2)
    return 1;
  else if (n % 2 == 0)
    return 0;
  double sqrtn = sqrt(n);
  Loop(i, 3, sqrtn + 1)
  {
    if (n % i == 0)
    {
      return 0;
    }
    i++;
  }
  return 1;
}

vector<bool> seen;
vec first;
vec last;
void dfs(const Graph &G, ll v, ll &time)
{
  if (!(seen[v]))
  {
    seen[v] = true;
    first[v] = time++;
    for (auto next_v : G[v])
    {
      if (seen[next_v])
        continue;
      dfs(G, next_v, time);
    }
    last[v] = time++;
  }
}
int main()
{
  ll n;
  cin >> n;
  Graph G(n);
  loop(i, n)
  {
    ll u, k;
    cin >> u >> k;
    while (k--)
    {
      ll x;
      cin >> x;
      Gput(u - 1, x - 1);
    }
  }
  vec id(n);
  loop(i, n) id[i] = i + 1;
  seen.assign(n, false); // 全頂点を「未訪問」に初期化
  first.resize(n);
  last.resize(n);
  ll time = 1;
  loop(i, n) dfs(G, i, time);
  loop(i, n)
  {
    cout << id[i] << " " << first[i] << " " << last[i] << endl;
  }
  return 0;
}