If you can give me an answer with some explanation on what classes and methods d

Question

If you can give me an answer with some explanation on what classes and methods do, that would be great! Thanks in advance. (Java)

Problem:

Implement a Double linked List ADT to store a collection of integers.

1. a member function pushFront(data) that inserts a node with data at the front of the list

2. a member function pushBack(data) that appends a node with data at the back of the list

3. a member function popFront() that removes first node of the list.

4. a member function popBack() that removes last node of the list.

5. a member function insert(index, val) that inserts a new node with value "val" at a specific position mentioned by the index argument.

6. a member function deleteDuplicates(val) that deletes a node with that number and all its copies from the list, where these copies can be located anywhere in the list.

7. a member function mtoLastElement(M) that returns Mth to the last element of a list such that when M = 0, the last element of the list is returned.

8. a member function size() that returns the size of the list.

9. a member function reverseList() that reverses a linked list without recreating a temporary copy of this linked list. In other words, your function CAN NOT use the 'new' operator. Here is an example, if a list contains the following data items, 3 -> 5 -> 1 -> 7; this reverse() function will change the list to 7 -> 1 -> 5 -> 3.

10. a MemberFunction mergeLists(linkedList one, linkedList two) which will create a new list that contains the elements of two lists in sorted order(ascending). Assume the two lists are in sorted order for this case

Ex: one: 1 -> 3 -> 7 -> 25 -> 50 (sorted)

two: 5 -> 9 -> 11 - > 12 -> 29 (sorted)

result list : 1 -> 3 -> 5 -> 7 - > 9 -> 11 -> 12 -> 25 -> 29 -> 50 (Sorted)

Explanation / Answer

/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package chegg.september;

/**
*
* @author Sam
*/
public class DoublyLL<T> {
    class Node {
        T data;
        Node next;
        Node prev;

        public Node(T data, Node prev, Node next) {
            this.data = data;
            this.next = next;
            this.prev = prev;
        }
    }
  
    Node head, tail;

    public DoublyLL() {
        head = tail = null;
    }
  
    void pushFront(T data) {
        if (head == null) {
            head = tail = new Node(data, null, null);
            return;
        }
      
        head = new Node(data, null, head);
        head.next.prev = head;
    }
  
    void pushBack(T data) {
        if (tail == null) {
            head = tail = new Node(data, null, null);
            return;
        }
      
        tail = new Node(data, tail, null);
        tail.prev.next = tail;
    }
  
    T popFront() {
        if (head == null)
            return null;
        T tmp = head.data;
        head = head.next;
        head.prev = null;
        if (head == null)
            tail = null;
        return tmp;
    }
  
    T popBack() {
        if (tail == null)
            return null;
        T tmp = tail.data;
        tail = tail.prev;
        tail.next = null;
        if (tail == null)
            head = null;
        return tmp;
    }
      
}

Inplemented 4 methods. Due to very high volume, we can only solve first 4 methods.

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