PAIRPR1 Pair of primes

Problem : PAIRPR1

Given an integer nn (between 11 and 104104) find two prime numbers (possibly same) p1,p2p1,p2 such that p1+p2=np1+p2=n

In case there are multiple solutions, you can output any of them.

If there is no solution, then print -1 -1 instead.

#include <iostream>
using namespace std;

bool check_prime(int n);
int main()
{
    int t;
    cin>>t;
    while(t--)
    {
        int n,i;
        bool flag=false;
        cin >> n;
        for(i = 2; i <= n/2; ++i)
        {
            if (check_prime(i))
            {
                if (check_prime(n - i))
                {
                    cout<<i<<" "<<n-i<<endl;
                    flag = true;
                    break;
                }
            }
        }
        if (!flag)
        cout<<-1 <<" "<<-1<<endl;
    }
  return 0;
}
bool check_prime(int n)
{
    int i;
    bool is_prime=true;
    if(n==0||n==1)
    {
        is_prime = false;
    }
    for(i = 2; i <= n/2; ++i)
    {
        if(n%i==0)
        {
            is_prime = false;
            break;
        }
    }
    return is_prime;
}

See also  CHEFALT Alternating Subsequences