Question

Implement the following operation for doubly Linked List:

public void insertAt(int position, E data){

}

public void insertEnd(E data){

}

public void deleteAt(int position) {

}

public void deleteEnd(){

}

Answer 1

public void insertAt(int position, E data) {

Node newNode = new Node();

newNode.data = data;

Node ptr = head;

position = position - 1;

for (int i = 1; ; i++) {

if (ptr == null) {

break;

}

if (i == position) {

newNode.next = ptr.next;

ptr.next.prev = newNode;

ptr.next = newNode;

newNode.prev = ptr;

break;

}

ptr = ptr.next;

}

}

public void insertEnd(E data) {

Node new_Node = new Node();

new_Node.data = data;

new_Node.next = head;

new_Node.prev = null;

if (head != null)

head.prev = new_Node;

head = new_Node;

}

private Node deleteNode(Node head, Node del)

{

if (head == null || del == null)

return null;

if (head == del)

head = del.next;

if (del.next != null)

del.next.prev = del.prev;

if (del.prev != null)

del.prev.next = del.next;

del = null;

return head;

}

public void deleteAt(int position)

{

if (head == null || n <= 0)

return;

Node current = head;

int i;

for (i = 1; current != null && i < position; i++)

{

current = current.next;

}

if (current == null)

return;

deleteNode(head, current);

}

NOTE: As per HOMEWORKLIB POLICY I am allowed to answer specific number of questions (including sub-parts) on a single post. Kindly post the remaining questions separately and I will try to answer them. Sorry for the inconvenience caused.