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++: // https://ei1333.github.io/luzhiled/
// http://beet-aizu.hatenablog.com/entry/2017/01/04/113233
// http://www.prefield.com/algorithm/
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using vl = vector<ll>;
using vd = vector<ld>;
using vs = vector<string>;
using vb = vector<bool>;
using vvl = vector<vector<ll>>;
using vvd = vector<vector<ld>>;
using vvs = vector<vector<string>>;
using vvb = vector<vector<bool>>;
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
template<class T> using vc = vector<T>;
template<class T> using vvc = vector<vector<T>>;
using Graph = vector<vector<ll>>;
const ll INF = 1LL << 60;
void init() {cin.tie(0);ios::sync_with_stdio(false);cout << fixed << setprecision(15);}
const ll tl= 1'000'000'007;
#define REP(i, n) for (ll i = 0; i < n; i++)
#define REREP(i, n) for (ll i = n; i >= 0; i--)
#define FOR(i, a, n) for (ll i = a; i < n; i++)
#define REFOR(i, n, a) for (ll i = n; i >= a; i--)
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() ) //被り削除
#define debug cout << "line : " << __LINE__ << " debug" << endl;
#define ini(...) int __VA_ARGS__; in(__VA_ARGS__)
#define inl(...) long long __VA_ARGS__; in(__VA_ARGS__)
#define ind(...) long double __VA_ARGS__; in(__VA_ARGS__)
#define ins(...) string __VA_ARGS__; in(__VA_ARGS__)
#define inc(...) char __VA_ARGS__; in(__VA_ARGS__)
void in(){} template <typename T,class... U> void in(T &t,U &...u){ cin >> t; in(u...);}
void out(){cout << endl;} template <typename T,class... U> void out(const T &t,const U &...u){ cout << t; if(sizeof...(u)) cout << " "; out(u...);}
template<typename T>void die(T x){out(x); exit(0);}
#define in1(A) REP(i,A.size()) in(A[i]);
#define in2(A,B) REP(i,A.size()) in(A[i],B[i]);
#define in3(s,t,u) REP(i,sz(s)){in(s[i] , t[i] , u[i]);}
#define in4(s,t,u,v) REP(i,sz(s)){in(s[i] , t[i] , u[i] , v[i]);}
#define each(x,v) for(auto& x : v)
#define all(v) (v).begin(),(v).end()
#define sz(v) ((int)(v).size())
struct Point{ ld x,y; };
ld dist(Point a, Point b){return sqrt(abs(a.x-b.x)*abs(a.x-b.x)+abs(a.y-b.y)*abs(a.y-b.y));} // ２点間の距離 
ll gcd(ll a, ll b) { return b != 0 ? gcd(b, a % b) : a; }
ll lcm(ll a,ll b){ return a / gcd(a,b) * b;} 
ll fact(ll n){ if(n < 2) return 1; return (n * fact(n-1))%tl; } //階乗
inline ll updiv(ll a,ll b){ return (a + b - 1) / b; } //切り上げ
template<typename T,typename U>ll ceil(T a,U b){return (a + b - 1) / b;}
template <class A, class B> inline bool chmax(A &a, const B &b) { return b > a && (a = b, true); }
template <class A, class B> inline bool chmin(A &a, const B &b) { return b < a && (a = b, true); }
//-------------------------------------------------------------------------------------------------
Graph g;
ll n;
vl memo;
vvl ans;
ll cnt;
// 訪ねた頂点をメモしていくタイプ
void memo_dfs(){
    vl A;
    A.pb(1);
    while(!A.empty()){
        ll p= A.back();
        A.pop_back();
        ans[p][0]= 1;
        memo[p]= 1;
        ll f=1;
        each(x,g[p]){
            if(memo[x]) continue;
            f=0;
            A.pb(x);
        }
    }
    return;
}

// 再帰によるdfs(閉路があるのでmemo必要)
void dfs(ll now,ll pre){
    memo[now]=1;
    cnt++;
    ans[now][0]= cnt;
    // out(now,cnt);
    each(next, g[now]){
        if(pre==next) continue;
        if(memo[next]) continue;
        dfs(next,now);
    }
    
    cnt++;
    ans[now][1]= cnt;
    return;
}

int main(){
    init();
    cin >> n;
    g.resize(n+1);
    memo.resize(n+1,0);
    ans.resize(n+1,vl(2,0));
    cnt=0;
    FOR(i,1,n+1){
        inl(u,k);
        REP(j,k){
            inl(x);
            g[u].pb(x);
        }
    }
    FOR(i,1,n+1){
        if(!memo[i]) dfs(i,-1);
    }
    
    FOR(i,1,n+1){
        out(i,ans[i][0],ans[i][1]);
    }
}

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

int t[(1<<18)];

void Set(int a,int b,int x,int k=0,int l=0,int r=(1<<17)){
  if(b<=l || r<=a)return;
  if(a<=l && r<=b){
    t[k]=max(t[k],x);
    return;
  }
  int m=(l+r)/2;
  Set(a,b,x,k*2+1,l,m);
  Set(a,b,x,k*2+2,m,r);
}

int Get(int i){
  i+=(1<<17)-1;
  int res=t[i];
  while(i){
    i=(i-1)/2;
    res=max(res,t[i]);
  }
  return res;
}

int n,q;
int value[100005];

int main(){
  value[0]=2147483647;

  scanf("%d %d",&n,&q);
  for(int i=1;i<=q;i++){
    int type;
    scanf("%d",&type);
    if(type==0){
      int l,r;
      scanf("%d %d %d",&l,&r,&value[i]);
      r++;
      Set(l,r,i);
    }else{
      int target;
      scanf("%d",&target);
      int ans=Get(target);
      printf("%d\n",value[ans]);
    }
  }
  return 0;
}

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, tt;
int M[N][N], color[N], d[N], f[N], nt[N]; 

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 = 0;
		while(!M[u][v] && v < n) {
			v++;
		} 
		if(v != n) {
			if(color[v] == WHITE) {
			   color[v] = GRAY;
			   d[v] = ++tt;
			   S.push(v); 	
			}
		} else {
		   color[u] = BLACK;
		   S.pop();
		   f[u] = ++tt;
		}
	} 
}


void dfs() {
	for(int i = 0; i < n; i++) {
	     color[i] = WHITE;
	}
	tt = 0;
		
	for(int u = 0; u < n; u++) {
		if(color[u]) dfs_visit(u);
	}

	
	for(int i = 0; i < n; i++) {
		cout << i + 1 << " " << d[i] << " " << f[i] << endl;	
	}
}

int main() {
	int k , u, 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 i = 0; i < k; i++) {
	        cin >> v;
	        v--;
		   M[u][v] = 1; 
     	}
	} 
	
	dfs();
	
	return 0;
}

C++: #include<stdio.h>
#include<stack>
using namespace std;
int begins[100] = {0},ends[100] , a[100][100],f[100]={0};
stack<int> tc;
int cnt = 0;
int n;
void inset(int u){
    int i;
    if(begins[u] != 0)return;
    begins[u] = ++cnt;
    tc.push(u);
 for(i = 1 ;i <= n ; i++){
    if( a[u][i] == 1 )
    {   a[i][u] = 0;
        a[u][i] = 0 ;
     inset(i);
    }
    }
ends[tc.top()] = ++cnt;
tc.pop();
if(tc.empty())return;
}
int main(){
int i , j , k , m , t;
scanf("%d",&n);
for(i = 0  ; i < n ; i ++){
    scanf("%d%d",&m,&k);
    while(k--){
        scanf("%d",&t);a[m][t] = 1;
    }
}
inset(1);
for(i = 1 ; i <= n ; i++){
    printf("%d %d %d\n",i,begins[i],ends[i]);
}
return 0;
}