[APS] Delete Even Duplicates

// 2021 juni - termin 2
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;

class SLLNode<E> {
    protected E element;
    protected SLLNode<E> succ;

    public SLLNode(E elem, SLLNode<E> succ) {
        this.element = elem;
        this.succ = succ;
    }

    @Override
    public String toString() {
        return element.toString();
    }
}

class SLL<E> {
    private SLLNode<E> first;

    public SLL() {
        // Construct an empty SLL
        this.first = null;
    }

    public void deleteList() {
        first = null;
    }

    public int length() {
        int ret;
        if (first != null) {
            SLLNode<E> tmp = first;
            ret = 1;
            while (tmp.succ != null) {
                tmp = tmp.succ;
                ret++;
            }
            return ret;
        } else
            return 0;

    }
    @Override
    public String toString() {
        String ret = new String();
        if (first != null) {
            SLLNode<E> tmp = first;
            ret += tmp + " ";
            while (tmp.succ != null) {
                tmp = tmp.succ;
                ret += tmp + " ";
            }
        } else
            ret = "";
        return ret;
    }

    public void insertFirst(E o) {
        SLLNode<E> ins = new SLLNode<E>(o, first);
        first = ins;
    }

    public void insertAfter(E o, SLLNode<E> node) {
        if (node != null) {
            SLLNode<E> ins = new SLLNode<E>(o, node.succ);
            node.succ = ins;
        }
    }

    public void insertBefore(E o, SLLNode<E> before) {

        if (first != null) {
            SLLNode<E> tmp = first;
            if(first==before){
                this.insertFirst(o);
                return;
            }
            //ako first!=before
            while (tmp.succ != before)
                tmp = tmp.succ;
            if (tmp.succ == before) {
                SLLNode<E> ins = new SLLNode<E>(o, before);
                tmp.succ = ins;
            } else {
                System.out.println("Elementot ne postoi vo listata");
            }
        } else {
            System.out.println("Listata e prazna");
        }
    }
    public void insertLast(E o) {
        if (first != null) {
            SLLNode<E> tmp = first;
            while (tmp.succ != null)
                tmp = tmp.succ;
            SLLNode<E> ins = new SLLNode<E>(o, null);
            tmp.succ = ins;
        } else {
            insertFirst(o);
        }
    }

    public E deleteFirst() {
        if (first != null) {
            SLLNode<E> tmp = first;
            first = first.succ;
            return tmp.element;
        } else {
            System.out.println("Listata e prazna");
            return null;
        }
    }

    public E delete(SLLNode<E> node) {
        if (first != null) {
            SLLNode<E> tmp = first;
            if(first ==node){
                return this.deleteFirst();
            }
            while (tmp.succ != node && tmp.succ.succ != null)
                tmp = tmp.succ;
            if (tmp.succ == node) {
                tmp.succ = tmp.succ.succ;
                return node.element;
            } else {
                return null;
            }
        } else {
            return null;
        }

    }

    public SLLNode<E> getFirst() {
        return first;
    }
    public SLLNode<E> find(E o) {
        if (first != null) {
            SLLNode<E> tmp = first;
            while (tmp.element != o && tmp.succ != null)
                tmp = tmp.succ;
            if (tmp.element == o) {
                return tmp;
            }
        }
        return first;
    }
}

public class DeleteEvenDuplicates {
    public static void deleteEven(SLL<Integer> list1) {
        //todo: enter code here
        SLLNode<Integer> i= list1.getFirst();
        SLLNode<Integer> j= list1.getFirst();
        int counter=0;

        while(i!=null){
            int broj= i.element;
            j=list1.getFirst();
            counter=0;
            while(j!=null){
                if(j.element==broj) counter++;
                j=j.succ;
            }
            if(counter>0&&counter%2==0){
                j= list1.getFirst();
                while(j!=null){
                    if(j.element==broj){
                        list1.delete(j);
                    }
                    j=j.succ;
                }
            }

            i=i.succ;
        }

    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = Integer.parseInt(scanner.nextLine());
        SLL<Integer> list1 = new SLL<Integer>();

        //todo: enter code here
        String[] niza= scanner.nextLine().split("\\s+");
        for(int i=0;i<n;i++){
            list1.insertLast(Integer.parseInt(niza[i]));
        }


        deleteEven(list1);
        //todo: enter code here
        System.out.println(list1.toString());
    }
}

/*
Test
9
1 10 2 3 5 2 10 3 3

1 3 5 3 3

Test
10
15 3 15 2 4 9 3 15 8 15

2 4 9 8
*/