ex 1

import java.util.HashMap;
import java.util.Map;

public class Main {

    public static int[] function1(int[] a, int[] b){
        int[] c = new int[a.length];
        Map<Integer, Integer> bMap = new HashMap<>();
            for (int i=0; i<b.length; i++){
                if(!bMap.containsKey(b[i])){
                    bMap.put(b[i],1);
                }else {
                    bMap.put(b[i], bMap.get(b[i])+1);
                }
            }

        int k = 0;
            for (int i=0; i<a.length; i++){

                if(!bMap.containsKey(a[i]) || !isPrimeNumber(bMap.get(a[i]))){
                    c[k] = a[i];
                    k++;
                }

            }

        return c;
    }


    public static boolean isPrimeNumber(int n){
        if((n==0) || (n==1))
            return false;
        for (int i=2; i<n; i++){
            if(n%i == 0)
                return false;
        }

        return true;
    }


    public static void main(String[] args) {
        int[] a = {2,3,9,2,5,1,3,7,10};
        int[] b = {2,1,3,4,3,10,6,6,1,7,10,10,10};
        int[] c = function1(a,b);
        for (int i=0; i<c.length; i++){
            if(c[i] != 0)
                System.out.print(c[i] + " ");
        }
    }
}