Primality Checking

/* Bismillahir Rahmanir Rahim Time Complexity: O(sqrt(n)/2) */ #include<bits/stdc++.h> #define ll long long using namespace std; ll n, i; bool isPrime(int n){ if(n<2 || (n!=2 && n%2==0)) return false; else{ for(i=3; i*i<=n; i+=2){ if(n%i==0) return false; } } return true; } int main(){ while(cin>>n){ if(isPrime(n)) cout<<"Prime"<<endl; else cout<<"Not Prime"<<endl; } return 0; }