[APS] Find Pairs

//2020 prv kolokvium - termin 1
import java.util.NoSuchElementException;
import java.util.Scanner;
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 = "Prazna lista!!!";
        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;
        } else {
            System.out.println("Dadenot jazol e null");
        }
    }

    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 {
                System.out.println("Elementot ne postoi vo listata");
                return null;
            }
        } else {
            System.out.println("Listata e prazna");
            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;
            } else {
                System.out.println("Elementot ne postoi vo listata");
            }
        } else {
            System.out.println("Listata e prazna");
        }
        return first;
    }

}

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();
    }
}
public class FindPairs {
    public static void findPairs(SLL<Integer> list) {
        SLLNode<Integer> temp1 = list.getFirst();
        SLLNode<Integer> temp2 = list.getFirst();
        while (temp1.succ != null) {
            temp2 = temp1.succ;
            while (true) {
                if(temp2==null) break;
                if (temp1.element % 2 == temp2.element % 2) {
                    if (temp1.element % 2 == 1) {
                        temp1.element -= temp2.element;
                        list.delete(temp2);
                        break;
                    } else {
                        temp1.element += temp2.element;
                        list.delete(temp2);
                        break;
                    }

                }
                temp2=temp2.succ;
            }
            temp1=temp1.succ;
            if(temp1==null) break;
        }
    }
        public static void main (String[]args){
            SLL<Integer> list = new SLL<Integer>();
            Scanner input = new Scanner(System.in);
            int n = Integer.parseInt(input.nextLine());
            String[] broevi = input.nextLine().split("\\s+");
            for (int i = 0; i < n; i++) {
                list.insertLast(Integer.parseInt(broevi[i]));
            }
            findPairs(list);
            System.out.println(list);
        }
    }
/*
TestCase1
8
1 2 3 4 5 6 7 8
-2 6 -2 14
TestCase2
10
7 12 24 2 6 32 11 44 8 10
-4 36 8 76 18
 */