Go: package main

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

type TimeRecord struct {
	discoverTime int
	finishTime   int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	timeRecordMap := make([]TimeRecord, n)
	childrenMap := make([][]int, n)
	for i := 1; i <= n; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		timeRecordMap[node-1] = TimeRecord{-1, -1}

		childNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		childrenMap[node-1] = make([]int, childNum)
		for j := 0; j < childNum; j++ {
			child, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			childrenMap[node-1][j] = child
		}
	}

	// TODO: always start with 1?
	timer := 1
	visit(1, &timer, childrenMap, timeRecordMap)
	for k, v := range timeRecordMap {
		fmt.Printf("%d %d %d\n", k+1, v.discoverTime, v.finishTime)
	}
}

func visit(currentNode int, timer *int, childrenMap [][]int, timeRecordMap []TimeRecord) {
	if timeRecordMap[currentNode-1].discoverTime > 0 {
		return
	}
	children := childrenMap[currentNode-1]
	timeRecordMap[currentNode-1] = TimeRecord{*timer, timeRecordMap[currentNode-1].finishTime}
	(*timer)++
	for i := 0; i < len(children); i++ {
		visit(children[i], timer, childrenMap, timeRecordMap)
	}
	timeRecordMap[currentNode-1] = TimeRecord{timeRecordMap[currentNode-1].discoverTime, *timer}
	(*timer)++
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

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;
}