Go: package main

import "fmt"

func main() {
    var n, m int
    fmt.Scan(&n)

    u := make([]string, 300)

    for i := 0; i < n; i++ {
        fmt.Scan(&u[i])
    }

    fmt.Scan(&m)

    is_lock := true
    for i := 0; i < m; i++ {
        var t string
        fmt.Scan(&t)

        is_include := false
        for j := 0; j < n; j++ {
            if t == u[j] {
                is_include = true
                break
            }
        }
        if is_include == false {
            fmt.Printf("Unknown %s\n", t)
        } else if (is_lock) {
            fmt.Printf("Opened by %s\n", t)
            is_lock = false
        } else {
            fmt.Printf("Closed by %s\n", t)
            is_lock = true
        }
    }
}

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

int main() {

  long long int n;

  while( cin >> n ) {

    vector< string > id;

    for ( long long int i = 0; i < n; i++ ) {

      string in;
      cin >> in;
      id.push_back( in );

    }

    sort( id.begin(), id.end() );

    long long int m;
    cin >> m;

    long long int k = 0;

    for ( long long int i = 0; i < m; i++ ) {

      string in;
      cin >> in;

      if ( binary_search( id.begin(), id.end(), in ) ) {
	if ( k == 0 ) {
	  k = 1;
	  cout << "Opened by " << in << endl;
	}else {
	  k = 0;
	  cout << "Closed by " << in << endl;
	}
      }else {
	cout << "Unknown by " << in << endl;
      }

    }

  }

  return 0;

}

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

using namespace std;

int main(){
  int n,m;
  vector<string> u(257);
  string t;
  cin >> n;
  for(int i=0;i<n;i++){
    cin >> u[i];
  }
  cin >> m;
  bool open=false;//opened : true //closed : false
  for(int i=0;i<m;i++){
    cin >> t;
    if(find(u.begin(),u.end(),t)!=u.end()){
      if(open){
        cout << "Closed by " << t << endl;
        open = false;
      }else{
        cout << "Opened by " << t << endl;
        open = true;
      }
    }else{
      cout << "Unknown " << t << endl;
    }
  }
}

C++: /*Function Template*/
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef pair<ll,ll> pint;
const int MAX = 510000;
const int MOD = 1000000007;
#define rep(i, n) for(ll i = 0; i < (n); i++)
#define Rep(i, n) for(ll i = 1; i < (n); i++)
#define ALL(a)  (a).begin(),(a).end()
#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
ll fac[MAX], finv[MAX], inv[MAX];


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;
}
// テーブルを作る前処理
void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (ll i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }

}
ll Len(ll n) {
  ll s=0;
  while(n!=0) s++, n/=10;
  return s;
}


ll Sint(ll n) {
  ll m=0,s=0,a=n;
  while(a!=0) s++, a/=10;
  for(ll i=s-1;i>=0;i--) m+=n/((ll)pow(10,i))-(n/((ll)pow(10,i+1)))*10;
  return m;
}


ll Svec(vector<ll> v){
  ll n=0;
  for(ll i=0;i<v.size();i++) n+=v[i];
  return n;
}


ll GCD(ll a,ll b) {
  return b ? GCD(b,a%b) : a;
}


ll LCM(ll a,ll b){
  return a/GCD(a,b)*b;
}


ll Factorial(ll n){
  ll m=1;
  while(n>=1) m*=n,n--;
  return m;
}

void runlength(string s,vector<pair<char,ll>> &p){
  ll x=1;
  if(s.size()==1){
    p.push_back(pair<char,ll>(s[0],1));
  }
  for(ll i=0;i<s.size()-1;i++){
    if(s[i]==s[i+1]){
      x++;
      if(i==s.size()-2){
        p.push_back(pair<char,ll>(s[i],x));
      }
    }else{
      p.push_back(pair<char,ll>(s[i],x));
      x=1;
      if(i==s.size()-2){
        p.push_back(pair<char,ll>(s[s.size()-1],x));
      }
    }
  }
}




ll COM(ll n,ll k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

const int MAX_N=100010;
vector<bool> sieve_of_eratosthenes(){
  vector<bool> isPrime(MAX_N+1,true);
  for(int i=2;i<=MAX_N;i++){
    if(isPrime[i]){
      for(int j=2*i;j<=MAX_N;j+=i){
        isPrime[j]=false;
      }
    }
  }
  return isPrime;
}

vector<pint> prime_factorize(ll n){
  vector<pint> ans;
  for(ll p=2;p<=sqrt(n);p++){
    if(n%p!=0) continue;
    ll cnt=0;
    while(n%p==0){
      n/=p;
      cnt++;
    }
    ans.push_back(make_pair(p,cnt));
  }
  if(n!=1) ans.push_back(make_pair(n,1));
  return ans;
}

/*↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓*/
int main() {
  IOS;
  ll n;cin>>n;
  map<string,ll> mp;
  rep(i,n){
    string s;cin>>s;
    mp[s]++;
  }
  ll m;cin>>m;
  vector<string> w(m);
  rep(i,m) cin>>w[i];
  ll flag=0;
  rep(i,m){
    if(mp[w[i]]>=1){
      if(flag%2==0){
        cout<<"Opened by "<<w[i]<<endl;
        flag++;
      }else{
        cout<<"Closed by "<<w[i]<<endl;
        flag++;
      }
    }else{
      cout<<"Unknown "<<w[i]<<endl;
    }
  }
  
}

C++: #include <iostream>
#include <string>
using namespace std;
 
bool flag;
 
bool check(string t, string u){
 if(u==t){
  if(!flag)cout << "Opened by " << t << endl;
  else cout << "Closed by " << t << endl;
  flag ^= 1;
  return true;
 }
 return false;
}
 
 
int main(){
 int n,i,j,m;
 bool ans=false;
 string u[260],t[260];
 cin >> n;
 for(i=0;i<n;i++)cin >> u[i];
 cin >> m;
 for(i=0;i<m;i++)cin >> t[i];
 for(i=0;i<m;i++){
  ans = false;
  for(j=0;j<n;j++)ans|=check(t[i],u[j]);
  if(!ans)cout << "Unknown " << t[i] << endl;
 }
 return 0;
}