câu 12 :

#include <bits/stdc++.h>

using namespace std;

#define int long long

bool check (int x)
{
  for (int i = 2; i <= sqrt(x); ++i)
  if (x % i == 0) return false;
  return x > 1;
}
int n;
main() {
  //freopen(".inp", "r", stdin);
  //freopen(".out", "w", stdout);
  ios_base::sync_with_stdio(0);
  cin.tie(nullptr);
  cin >> n;
  if (check(n)) cout << "YES";
  else cout << "NO";
}
    

câu 13:

#include <bits/stdc++.h>

using namespace std;

#define int long long

bool check (int n)
{
  int s = 0;
  for (int i = 1; i <= sqrt(n); ++i)
  {
    if (n % i == 0){
      s += n / i + i;
    }
  }
  int k = sqrt(n);
  if (k * k == n) s -= k;
  return s - n == n; 
}
int n;
main() {
  //freopen(".inp", "r", stdin);
  //freopen(".out", "w", stdout);
  ios_base::sync_with_stdio(0);
  cin.tie(nullptr);
  cin >> n;
  if (check(n)) cout << "YES";
  else cout << "NO";
}
    

câu 14:

#include <bits/stdc++.h>

using namespace std;

#define int long long

int rev (int n)
{
  int s = 0;
  while (n)
  {
    s = s * 10 + (n % 10);
    n /= 10;
  }
  return s;
}
int n;
main() {
  //freopen(".inp", "r", stdin);
  //freopen(".out", "w", stdout);
  ios_base::sync_with_stdio(0);
  cin.tie(nullptr);
  cin >> n;
  cout << rev(n);
}
    

câu 14:

#include <bits/stdc++.h>

using namespace std;

#define int long long

int n, a[10000005], i;
main() {
  //freopen(".inp", "r", stdin);
  //freopen(".out", "w", stdout);
  ios_base::sync_with_stdio(0);
  cin.tie(nullptr);
  cin >> n;
  for (i = 0; n > 0; ++i)
  {
    a[i] = n % 2;
    n /= 2;
  }
  for (i = i - 1; i >= 0; --i)
  {
    cout << a[i];
  }
}
    

câu 15:

#include <bits/stdc++.h>

using namespace std;

#define int long long

int n, m;
main() {
  //freopen(".inp", "r", stdin);
  //freopen(".out", "w", stdout);
  ios_base::sync_with_stdio(0);
  cin.tie(nullptr);
  cin >> n >> m;
  cout << __gcd(n , m) << " " << n * m / __gcd(n , m);
}
    

12:

#include <bits/stdc++.h>
using namespace std;
#define int long long
bool prime(int x){
	if(x<2)return false;
	for(int i=2;i*i<=x;i++){
		if(x%i==0)return false;
	}
	return true;
}
signed main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int n;
	cin>>n;
	if(prime(n))cout<<"YES";
	else cout<<"NO";
}

bài 13:

#include <bits/stdc++.h>
using namespace std;
#define int long long
bool perfect(int x){
	int ans=1;
	for(int i=2;i*i<=x;i++){
		if(x%i==0){
			if(i!=x/i){
				ans+=x/i;
			}
			ans+=i;
		}
	}
	return ans==x;
}
signed main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int n;
	cin>>n;
	if(perfect(n))cout<<"YES";
	else cout<<"NO";
}

14:

#include <bits/stdc++.h>
using namespace std;
#define int long long
int palin(int x){
	int ans=0;
	while(x){
		ans=ans*10+x%10;
		x/=10;
	}
	return ans;
}
signed main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int n;
	cin>>n;
	cout<<palin(n);
}

15:

#include <bits/stdc++.h>
using namespace std;
#define int long long
string binary(int x){
	string ans="";
	while(x){
		ans=char(x%2+'0')+ans;
		x/=2;
	}
	return ans;
}
signed main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int n;
	cin>>n;
	cout<<binary(n);
}

16:

#include <bits/stdc++.h>
using namespace std;
#define int long long
int gcd(int a,int b){
	if(b==0)return a;
	return gcd(b,a%b);
}
int lcm(int a,int b){
	return a*b/gcd(a,b);
}
signed main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int m,n;
	cin>>m>>n;
	cout<<gcd(m,n)<<"\n"<<lcm(m,n);
}