Go: #include <bits/stdc++.h>
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, tt;
vector<vector<int>> M(N, vector<int>(N));
vector<int> color(N), d(N), f(N);

void dfs_visit(int u) {
  color[u] = GRAY;
  d[u]     = ++tt;
  for (int v = 0; v < n; v++) {
    if (M[u][v] == 0) continue;
    if (color[v] == WHITE) { dfs_visit(v); }
  }
  color[u] = BLACK;
  f[u]     = ++tt;
}

void dfs() {
  tt = 0;

  for (int u = 0; u < n; u++) {
    if (color[u] == WHITE) dfs_visit(u);
  }
  for (int u = 0; u < n; u++) {
    printf("%d %d %d\n", u + 1, d[u], f[u]);
  }
}

int main() {
  int u, v, k;
  cin >> n;
  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++: #include <iostream>
//#include <iomanip>
//#include <string>
#include <vector>
#include <algorithm>
//#include <utility>
//#include <set>
//#include <map>
//#include <queue>
//#include <deque>
//#include <bitset>
//#include <math.h>
using namespace std ;
using ll = long long ;
//using ld = long double ;
using vll = vector<ll> ;
using vvll = vector<vll> ;
//using vc = vector<char> ;
//using vvc = vector<vc> ;
//using vb = vector<bool> ;
//using vvb = vector<vb> ;
//using pll = pair<ll,ll> ;
#define all(v) v.begin(),v.end()
//ll mod = 1000000007 ;
//long double pie = acos(-1) ;
//ll INF = 1000000000000 ;

//void yorn(bool a){if(a) cout << "Yes" << endl ; else cout << "No" << endl ;}
//void YorN(bool a){if(a) cout << "YES" << endl ; else cout << "NO" << endl ;}
//ll gcd(long long a,long long b){if(b==0) return a ; return gcd(b,a%b) ;}
//ll lcm(long long a,long long b){return a/gcd(a,b)*b ;}
//ll sa(long long a,long long b){if(a>b) return a-b ; return b-a ;}
//void fix_cout(){cout << fixed << setprecision(20) ;}
//void chmin(ll &a,ll b){if(a>b) a = b ;}

ll cnt = 1 ;

void DFS(vvll &g,vvll &ans,ll p){
	if(ans.at(p).at(0)!=-1) return ;
	ans.at(p).at(0) = cnt ;
	cnt++ ;
	for(int i=0;i<g.at(p).size();i++){
		DFS(g,ans,g.at(p).at(i)) ;
	}
	ans.at(p).at(1) = cnt ;
	cnt++ ;
}

int main(){
	ll n ; cin >> n ;
	vvll g(n,vll(0)) ;
	for(int i=0;i<n;i++){
		ll a,b ;
		cin >> a >> b ;
		vll c(b) ;
		for(int j=0;j<b;j++) cin >> c.at(j) ;
		sort(all(c)) ;
		for(int j=0;j<b;j++) g.at(i).emplace_back(c.at(j)-1) ;
	}
	vvll ans(n,vll(2,-1)) ;
	for(int i=0;i<n;i++){
		if(ans.at(i).at(0)==-1) DFS(g,ans,i) ;
	}
	for(int i=0;i<n;i++) cout << i+1 << " " << ans.at(i).at(0) << " " << ans.at(i).at(1) << "\n" ;
}

C++: #include <iostream>
#include <vector>
using namespace std;

vector<int> G[100];
pair<int, int> T[100];
const int Inf = 10000*100000+100;
int timer = 1;

int main() {
  void dfs(int cur);
  int n;
  cin >> n;
  for (int i = 0; i < n; i++)
  {
    int u, k;
    cin >> u >> k;
    for (int l = 0; l < k; l++) {
      int v;
      cin >> v;
      G[i].push_back(v - 1);
    }
    T[i] = make_pair(Inf, Inf);
  }
  for (int i = 0; i < n; i++) {
    if (T[i].first == Inf) {
      dfs(i);
    }
  }
  for (int i = 0; i < n; i++)
  {
    cout << i + 1 << " " << T[i].first << " " << T[i].second << endl;
  }
}

void dfs(int cur) { // cur を訪問
  // cur の訪問時刻を記録
  T[cur].first = timer;
  timer += 1;
  // 動作確認用表示
  for (int dst : G[cur]) { // 全ての節点 dst について
    if (T[dst].first == Inf)
    { // cur から dst に辺があり，dst を未訪問なら
      dfs(dst);
    }
  }
  T[cur].second = timer;
  timer += 1;
}

C++: #include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<math.h>
#include<stack>
#include<queue>
#include<vector>
#include<algorithm>
#include<string>
#include<iostream>
using namespace std;
static const int N=105;
int M[N+1][N+1];
void graph(int n){
    for(int i=1;i<=n;i++){
        int garbage;cin>>garbage;
        int k;cin>>k;
        for(int j=1;j<=k;j++){
            int l;cin>>l;
            M[i][l]=1;
        }
    }
}
int d[N],f[N],t=1,n;
stack <int>S;
void dfs(){
    S.push(1);
    d[1]=t;
    while(S.empty()!=true){
        int flag=0,i=1;
        while(flag==0 && i<=n){
            if(M[S.top()][i]==0){
                i++;
            }else{
                    flag++;
                for(int z=1;z<=n;z++) M[z][i]=0;
                
            }
        }
        t++;
        if(i>=n+1){
            f[S.top()]=t;
            S.pop();
        }else{
            S.push(i);
            d[i]=t;
        }
    }
}

int main(){
    cin>>n;
    graph(n);
    dfs();
    for(int i=1;i<=n;i++){
        cout<<i<<" "<<d[i]<<" "<<f[i]<<endl;
    }
    
    return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

using ll = long long;

ll MAX_N = 1e5;
vector<vector<ll> > graph(MAX_N);
vector<bool> visited(MAX_N);

// ALDS1_11_B
vector<ll> d(MAX_N);
vector<ll> f(MAX_N);
ll t = 0;

// O(E)
void dfs(ll u){
    visited[u] = true;
    // visit v
    d[u] = ++t;
    for(ll v: graph[u]){
        if(!visited[v]){
            dfs(v);
        }
    }
    f[u] = ++t;
}

// ALDS1_11_B: verified
int main(){
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    ll n; cin >> n;
    for(ll i=0;i<n;i++){
        ll u, k; cin >> u >> k;
        vector<ll> vs;
        for(ll j=0;j<k;j++){
            ll v; cin >> v;
            vs.push_back(v);
        }
        sort(vs.begin(), vs.end());
        for(ll j=0;j<k;j++){
            ll v = vs[j];
            graph[u - 1].push_back(v - 1);
        }
    }
    for(int i=0;i<n;i++){
        if(!visited[i]) dfs(i);
    }
    for(int i=0;i<n;i++) cout << i + 1 << " " << d[i] << " " << f[i] << endl;
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
#define white 0
#define gray 1
#define black 2
const int N=100;
int n,color[N],c[N][N],tt,f[N],d[N];
void dfs_visit(int u){
    color[u]=gray;
    f[u]=++tt;
    for(int v=0;v<n;v++){
        if(c[u][v]==0)continue;
        if(color[v]==white){
            dfs_visit(v);
        }
    }
    color[u]=black;
    d[u]=++tt;
}
void dfs(){
    memset(color,0,sizeof(color));
    memset(f,0,sizeof(f));
    memset(d,0,sizeof(d));
    tt=0;
    for(int u=0;u<n;u++){
        if(color[u]==white)
        dfs_visit(u);
    }
    for(int u=0;u<n;u++)
    {
        cout<<u+1<<" "<<f[u]<<" "<<d[u]<<endl;
    }
}
int main(){
    int u,v,k;
    cin>>n;
    memset(c,0,sizeof(c));
    for(int i=0;i<n;i++){
        cin>>u>>k;u--;
        for(int j=0;j<k;j++){
            cin>>v;v--;
            c[u][v]=1;
        }
    }
    dfs();
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vll = vector<ll>;
using vqi = vector<queue<int>>;

#define rep(i, n) for (int i = 0; i < (int)(n); i++)

void dfs(vqi &g, vi &d, vi &f, int v, int &t) {
  if (d[v] && g[v].empty()) {
    t--;
    return;
  }

  if (!d[v]) d[v] = t;

  while (!g[v].empty()) {
    int next = g[v].front(); g[v].pop();
    if (!d[next] )dfs(g, d, f, next, ++t);
  }

  f[v] = max(++t, f[v]);
}

int main() {
  int n;
  cin >> n;
  
  vqi g(n);
  rep(i, n) {
    int u, k;
    cin >> u >> k;

    rep(j, k) {
      int v;
      cin >> v;
      g[u - 1].push(v - 1);
    }
  }

  vi d(n), f(n);
  stack<int> s;
  s.push(0);

  int t = 1;
  rep(i, n) {
    dfs(g, d, f, i, t);
    t++;
  }

  rep(i, n) printf("%d %d %d\n", i + 1, d[i], f[i]);
}