Jander_Semester2/uebung_03/src/IntLinkedList.java

public class IntLinkedList {
    private IntListNode headNode;
    private IntListNode tailNode;
    private int size;
    public IntLinkedList() {
        headNode = null;
        tailNode = null;
        size = 0;
    }
    public void add(int value) {
        if (headNode == null) {
            headNode = new IntListNode(value, null, null);
            tailNode = headNode;

        }
        else {

            IntListNode newNode = new IntListNode(value, null, null);
            newNode.prevNode = tailNode;
            tailNode.nextNode = newNode;
            tailNode = newNode;
        }
        size++;
    }
    public int getSize() {
        return size;
    }
    public int get(int index){
        if (index < 0 || index > (size - 1)){
            throw new IllegalArgumentException("Index Out of Bounds");
        }
        if (index < size/2){
            int pos = 0;
            IntListNode curNode = headNode;
            while (pos < index){
                curNode = curNode.nextNode;
                pos++;
            }
            return curNode.value;
        }
        else {
            int pos = size - 1;
            IntListNode curNode = tailNode;
            while (pos > index){
                curNode = curNode.prevNode;
                pos --;
            }
            return curNode.value;
        }
    }

    public void remove(int index){
        if (index < 0 || index > (size - 1)){
            throw new IllegalArgumentException("Index Out of Bounds");
        }
        if(index == 0){
            if(size == 1){
                headNode = null;
                tailNode = null;
            }
            else {
                headNode = headNode.nextNode;
                headNode.prevNode = null;
            }
            size --;
            return;
        }
        if (index == (size - 1)){

            tailNode = tailNode.prevNode;
            tailNode.nextNode = null;
            size --;
            return;
        }

        if (index < size/2){
            int pos = 0;
            IntListNode curNode = headNode;
            while (pos < index){
                curNode = curNode.nextNode;
                pos++;
            }
            // Set the prev of the following node so pos +1
            curNode.nextNode.prevNode = curNode.prevNode;

            // Then set the next of the previous node;
            curNode.prevNode.nextNode = curNode.nextNode;

            size--;

        }
        else {
            int pos = size - 1;
            IntListNode curNode = tailNode;
            while (pos > index){
                curNode = curNode.prevNode;
                pos --;
            }
            // Set the prev of the following node so pos +1
            curNode.nextNode.prevNode = curNode.prevNode;

            // Then set the next of the previous node;
            curNode.prevNode.nextNode = curNode.nextNode;

            size--;
        }
    }


}