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 <iostream>
#include<string>
#include<cmath>
#include<algorithm>
#include<cctype>
#include<queue>
#include<stack>
#include<stdio.h>
#include<vector>
#include<set>
#include<map>
#include<array>
#include<iomanip>
#define rep(i,n) for(int i=0;i<n;i++)
typedef int long long ll;

using namespace std;
static const int WHITE =0;
static const int GRAY=1;
static const int BLACK=2;
static const int N=100;

int n,color[N],tt,d[N],f[N];
int M[N][N];
int nt[N];
int next(int u){
    for(int v=nt[u];v<n;v++){
        nt[u]=v+1;//頂点に複数頂点隣接してる場合、小さいのから取り出せるように、
        //nt[u]nextで渡した頂点の数がはいる
        if(M[u][v])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){
            if(color[v]==WHITE){
                color[v]=GRAY;
                d[v]=++tt;
                S.push(v);
            }
        }else{
            S.pop();
            color[v]=BLACK;
            f[u]=++tt;
        }
    }
    
}

void dfs(){
    
    rep(i,n){color[i]=WHITE;nt[i]=0;}tt=0;
    
    
    rep(i,n){
        if(color[i]==WHITE){
            dfs_visit(i);
           }
    }
        
        
    rep(i,n){
        
        cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
    }
    
    
    
    
    
}



int main(){
    
    cin>>n;
    rep(i,n){
        int k,l;cin>>k>>l;
        k--;
        for(int j=0;j<l;j++){
            int u;
            cin>>u;
            M[k][u-1]=1;
        }
    }
  /*  rep(i,n){
        rep(j,n){cout<<M[i][j];}
    cout<<endl;
    }*/
    dfs();
    
    
return 0;
}

C++: #include <iostream>
#include <utility>
#include <string>
#include <algorithm>
#include <set>
#include <queue>
#include <vector>
#define MAX 10010
#define rep(i,p) for(int i=0;i<p;i++)
#define pb push_back
using namespace std;
int n,hoge,foo,visit_time=1;
int graph[MAX][MAX] = {0};
int d[MAX]; // ????????????
int f[MAX]; // ??£??\????????????????????????

void dfs (int cur) {
  // visiting cur
  d[cur] = visit_time;
  visit_time++;

  rep(dst,n) {
    if (graph[cur][dst] == 1 && d[dst] == -1) dfs(dst);
  }
  f[cur] = visit_time;
  visit_time++;
}

int main(){
  cin >> n;
  rep(i,n) {
    d[i] = -1;
    f[i] = -1;
  }
  rep(i,n) {
    cin >> hoge >> foo;
    rep(j,foo) {
      cin >> hoge;
      graph[i][hoge-1] = 1;
    }
  }
  dfs(0);
  rep(i,n) cout << i+1 << " " << d[i] << " " << f[i] << endl;
  return 0;
}

C++: #include<bits/stdc++.h>
#define r(i,a,n) for(int i=a;i<n;i++)
using namespace std;
int n,u,k,v,a[101][101],start[101],end[101],p,f[101];
void dfs(int u){
	if(!f[u]){
    f[u]++;
    start[u]=++p;
    r(i,1,n+1)if(a[u][i])dfs(i);
    end[u]=++p;
  }
}
int main(){
	cin>>n;
	r(i,0,n){
    cin>>u>>k;
		r(i,0,k){
      cin>>v;
			a[u][v]++;
		}
	}
	r(i,1,n+1)if(!f[i])dfs(i);
	r(i,1,n+1)cout<<i<<' '<<start[i]<<' '<<end[i]<<endl;
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#define rep(i,n) for(int i=0;i<n;++i)
#define rep1(i,n) for(int i=1;i<=n;++i)
using namespace std;
class Graph{
private:
  int node;
  int edge_num;
  vector<vector<int>> edge;  
  vector<int> f;
  vector<int> d;
  int time;
public:
  //***************Constractor****************************
  Graph(int n,vector<int> a,vector<int> b){
    node = n;
    edge_num = a.size();
    time = 1;
    edge.resize(node);
    f.resize(node,0);
    d.resize(node);    
    rep(i,edge_num){
      edge[a[i]].push_back(b[i]);
    }
  }

  //***********************************************
  
  void simple_dfs(int v){
    f[v] = time++;
    for(auto w:edge[v]){
      if(f[w]>0) continue;
      simple_dfs(w);
    }
    d[v] = time++;
  }

  void run_dfs(int s){//check each node can reach goal
    rep(i,node){
      if(f[i]<=0) simple_dfs(i);
    }
  }

  void show(){
    rep(i,node){
      cout << i+1 << " " << f[i] << " " << d[i] << "\n";
    }
  }
};


int main()
{
  int n;
  cin >> n;
  vector<int> a,b;
  rep(i,n){
    int aa;cin >> aa;aa--;
    int m;cin >> m;
    rep(i,m){
      int bb;cin >> bb;bb--;
      a.push_back(aa);
      b.push_back(bb);      
    }
  }

  Graph gp(n,a,b);
  gp.run_dfs(0);
  gp.show();
  
  return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> pll;

vector<set<ll>> v(101);
vector<ll> st(101,-1);
vector<ll> et(101,-1);

ll dfs(ll n,ll time) {
  st[n]=time;
  time++;
  for(auto p:v[n]) {
    if(st[p]<0) {
      time=dfs(p,time);
    }
  }
  et[n]=time;
  return time+1;
}

int main() {
  ll n;
  cin >> n;
  for(ll i=0;i<n;i++) {
    ll f,tn;
    cin >> f >> tn;
    for(ll j=0;j<tn;j++) {
      ll temp;
      cin >> temp;
      v[f].insert(temp);
    }
  }
  for(ll i=1;i<=n;i++) {
    v[0].insert(i);
  }
  dfs(0,0);
  for(ll i=1;i<=n;i++) {
    cout << i << " " << st[i] << " " << et[i] << endl;
  }
}

C++: #include <iostream>
#include <stdio.h>
#include <vector>
#include <utility>
#include <string>
#include <algorithm>
#include <cmath>
#include <queue>
 
typedef long long ll;

#define rep(i,n) for(ll i = 0; i < n; i++)
 
using namespace std;
 
const ll INF = ll(1e18)+1;
const double PI=3.14159265358979323846;

vector<vector<int> > G(105);
vector<int> go(105), back(105);
vector<bool> seen(105);
int now=1;

void dfs(int s){

  go[s]   = now++;
  seen[s] = true;

  rep(i,G[s].size()){
    if(seen[G[s][i]]) continue;    
    dfs(G[s][i]);
  }
  
  back[s] = now++;
}

int main(){
  int n;
  cin >> n;
  rep(i,n){
    int u,k;
    cin >> u >> k;
    rep(j,k){
      int x;
      cin >> x;
      G[u].push_back(x);
    }    
  }
  for(int i=1; i<=n; i++) if(!seen[i]) dfs(i);
  rep(i,n){
    cout << i+1 << " " << go[i+1] << " " << back[i+1] << endl;
  }
}