Go: package main

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

const MAX = 101

var f [MAX]int
var d [MAX]int
var list [][]int
var sc = bufio.NewScanner(os.Stdin)

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func dfs(u, cnt int) int {
	if d[u] != 0 {
		return cnt
	}

	cnt++
	d[u] = cnt
	for _, next := range list[u] {
		cnt = dfs(next, cnt)
	}
	cnt++
	f[u] = cnt
	return cnt
}

func main() {
	n := scanInt()
	list = make([][]int, n+1)
	for i := 1; i <= n; i++ {
		u := scanInt()
		k := scanInt()
		for j := 0; j < k; j++ {
			n := scanInt()
			list[u] = append(list[u], n)
		}
	}

	cnt := 0
	for i := 1; i <= n; i++ {
		cnt = dfs(i, cnt)
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 1; i <= n; i++ {
		fmt.Fprint(w, i)
		fmt.Fprint(w, " ")
		fmt.Fprint(w, d[i])
		fmt.Fprint(w, " ")
		fmt.Fprint(w, f[i])
		fmt.Fprintln(w)
	}
	w.Flush()
}

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;
//?????\??????
int M[N][N];
//??°?????¶???????¢????
int color[N];
//??\??¶????????°??¶???
int d[N];
//??\??¶???????????¶???
int f[N];
//??¶???
int tt;

int nt[N];

//????????????????????????u?????????v
int next(int u){
    for(int v=0;v<n;v++){
        nt[u]=v+1;
        if(M[u][v]&&color[v]==WHITE)
            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&&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;
    tt=0;

    //??\????????????u?????????????????±?????????????´¢
    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();
}

C++: /**
 * @Author: yujirotakahashi
 * @Date:   2020-05-17T20:21:41+09:00
 * @Last modified by:   yujirotakahashi
 * @Last modified time: 2020-05-22T23:42:35+09:00
 */

#include<bits/stdc++.h>
using namespace std;

/*******  All Required define Pre-Processors and typedef Constants *******/
#define all(cont) cont.begin(), cont.end()
#define rall(cont) cont.end(), cont.begin()
#define rep(i,n) for(int i=0; i<(n); ++i)
#define rep1(i,n) for(int i=1; i<=(n); ++i)
#define Dcout(a) cout << setprecision(20) << a << endl
#define MP make_pair
#define PB push_back
#define EPS 1e-9
#define PI 3.1415926535897932384626433832795
#define MOD 1000000007
//const ll INF = (1LL << 60);
//const double pi=acos(-1.0);
using ll = long long;
using PAIR = pair<int, int>;
#define debug cout << "line : " << __LINE__ << " debug" << endl
/****** Template of some basic operations *****/
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
/**************************************/

/******** User-defined Function *******/
using Graph = vector<vector<int>>;
int n;
int m[100][100];
int color[100],d[100],f[100],tt;

int nt[100];

//color while-1 Gray-2 Black-3
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(int r){
    rep(i,n) nt[i] = 0;

    stack<int> S;
    S.push(r);
    color[r] = 1;
    d[r] = ++tt;

    while(!S.empty()){
        int u = S.top();
        int v = next(u);
        if(v != -1){
            if(color[v] == 0){
                color[v] = 1;
                d[v] = ++tt;
                S.push(v);
            }
        }else{
            S.pop();
            color[u] = 2;
            f[u] = ++tt;
        }
    }
}
/**************************************/

/********** Main()  function **********/
int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);

  cin >> n;
  rep(i,n)rep(j,n) m[i][j] = 0;

  rep(i,n){
      int u,k; cin >> u >> k;
      u--;
      rep(j,k){
          int v; cin >> v;
          v--;
          m[u][v] = 1;
      }
  }

  //dfs

  rep(i,n){
       color[i] = 0;
       nt[i] = 0;
   }
  tt = 0;

  rep(u,n){
      if(color[u] == 0) dfs(u);
  }

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

  return 0;
}
/********  Main() Ends Here *************/

C++: #include<bits/stdc++.h>
#define F first
#define S second
using namespace std;
void func(int p);
typedef pair<int,int>P;
int n;
array<array<int,101>,101>arr;
array<P,101>arrp;
array<bool,101>arrb;
int Time;
int main(void){
	int u,k,v;
	int i,j;
	cin>>n;
	for(i=1;i<=n;i++){
		for(j=1;j<=n;j++){
			arr[i][j]=0;
		}
	}
	for(i=0;i<n;i++){
		cin>>u>>k;
		for(j=0;j<k;j++){
			cin>>v;
			arr[u][v]=1;
		}
	}
	arrb.fill(false);
	Time=0;
	for(i=1;i<=n;i++){
		if(!arrb[i]){
			func(i);
		}
	}
	for(i=1;i<=n;i++){
		cout<<i<<" "<<arrp[i].F<<" "<<arrp[i].S<<endl;
	}
	return 0;
}
void func(int p){
	int i,j;
	//cout<<p<<endl;
	arrb[p]=true;
	Time++;
	arrp[p].F=Time;
	for(i=1;i<=n;i++){
		if(arr[p][i]==1){
			if(!arrb[i]){
				func(i);
			}
		}
	}
	Time++;
	arrp[p].S=Time;
}