Quà tặng

#include<iostream>
using namespace std;
int n, res, Count;
int A[55];
int B[55];
bool checkPrime(int x)
{
    if (x == 2) return true;
    for (int i = 2; i <= x / 2; i++)
    {
        if (x % i == 0) return false;
    }
    return true;
}
void Try(int i)
{
    B[i] = 1;
    Count++;
    for (int j = 0; j < n; j++)
    {
        if (B[j] == 0 && checkPrime(A[i] + A[j]))
        {
            if (Count == n-1&&checkPrime(A[j]+A[0]))
            {
                res += 1;
            }
            else
            {
                Try(j);
            }
        }
    }
    B[i] = 0;
    Count--;
}
int main()
{
    freopen("input.txt", "r", stdin);
    int testCase;
    cin >> testCase;
    for (int tc = 0; tc < testCase; tc++)
    {
        cin >> n;
        res = 0;
        for (int i = 0; i < n; i++)
        {
            cin >> A[i];
            B[i] = 0;
        }
        Count = 0;
        Try(0);
        cout << res << endl;
    }
    return 0;
}