Help me in solving FIZZBUZZ2305 problem

help
,
1

My issue

my code gives W.A. for 2nd test case what’s the issue here include <bits/stdc++.h>
define ll long long
using namespace std;
bool isprime(ll n){
for(int i=2;i*i<=n;i++){
if(n%i==0) return false;
}
return true;
}

int main() {
// your code goes here
ll t; cin>>t;
while(t–){
ll n; cin>>n;
ll x=0,i=0,cnt=0;
for( i=3;i<=n/2;i++){
if(isprime(i)) {cnt=1;break;}
}

 if(cnt) x=n/i;
 else{
     if(n<=2) x=0;
 else if(isprime(n)) x=1; }
if(x%2) cout<<"Alice"<<endl;
else cout<<"Bob"<<endl;
}
return 0;

}
can anyone please tell me??

My code

#include <bits/stdc++.h>
#define ll long long
using namespace std;
bool isprime(ll n){
    for(int i=2;i*i<=n;i++){
        if(n%i==0) return false;
    }
    return true;
}

int main() {
	// your code goes here
	ll t; cin>>t;
	while(t--){
	    ll n; cin>>n;
	    ll x=0,i=0,cnt=0;
	  for( i=3;i<=n/2;i++){
	     if(isprime(i)) {cnt=1;break;}
	  }
	  
	 if(cnt) x=n/i;
	 else{
	     if(n<=2) x=0;
	 else if(isprime(n)) x=1; }
	if(x%2) cout<<"Alice"<<endl;
	else cout<<"Bob"<<endl;
	}
	return 0;
}

Problem Link: FIZZBUZZ2305 Problem - CodeChef

2

The constraints are too high for you to check if the given number is prime in o(sqrt(n)) time.

As iceknight1093 states in his editorial:

Let p be an odd prime factor of N.
Then, note that p is also an odd prime factor of N−p, since N is itself a multiple of p.

Corrected o(1) Code:

#include <iostream>
using namespace std;

int main() {
	int t;
	cin>>t;
	while(t--)
	{
	    int n;
	    cin>>n;
	    if (n > 1 && n & 1)
	        cout<<"Alice\n";
	    else
	        cout<<"Bob\n";
	}
}

Another Corrected Code That’s almost as efficient as o(1):

#include<bits/stdc++.h>
using namespace std;
bool isPrime(int n) {
    if (n <= 1) {
        return false;
    }
    if (n <= 3) {
        return true;
    }
    if (n % 2 == 0 || n % 3 == 0) {
        return false;
    }
    for (int i = 5; i * i <= n; i += 6) {
        if (n % i == 0 || n % (i + 2) == 0) {
            return false;
        }
    }
    return true;
}

int solve(int n){
    if(n%2 == 0) return 1; // bob
    if(isPrime(n)) return 0; // alice
    for(int p=3;p<=n;p+=2){
        if((n%p == 0) && (isPrime(p))) return 0;//alice
    }
    return 1;
}

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0); 
    int t;  cin>>t;
    while(t--){
        int n;  cin>>n;
        bool result = solve(n); 
        if(result == false) cout<<"Alice\n";
        else cout<<"Bob\n";
    }
    return 0;
}