10-core-basic-linked-list

Computer Science

Linked List

In this activity, we're going to be creating a very basic linked list. It will allow you to add to either the head or the tail, but not include any additional methods to add or delete from the list. We will be adding those in a later code drill.

Instructions

• Copy your Node.js file from the previous activity into this folder. Our LinkedList.js fill will be importing it and using the constructor you created.

  • If you had trouble with the Node constructor, there is a completed one in the hint folder you can use.
  • For this activity, you should not access the value and next of a Node and operate on them directly. Instead, use the methods provided by the Node constructor in order to manipulate the values of the node.

• Within the LinkedList.js file, fill out the LinkedList constructor function by following the instructions below.

• Create a constructor function for a new LinkedList object that optionally takes in a value to instantiate the LinkedList with

  • The LinkedList object needs to keep track of the head node and the tail node.
    • The head node is the start of the linked list.
    • The tail node is the end of the linked list. Reaching this point means we've reached the end of the iteration.
    • If there are no nodes in the linked list, both the head and the tail should be null.
    • If there is only one node, the head and the tail should both point to it since it is both the start and end of the list.
  • The LinkedList object also needs to keep track of the length of the list.
  • If the user doesn't pass in a value when instantiating the list, then the head and tail should point to null and the length is 0
  • If the user does pass in a value when instantiating the list, then the head and tail should both point to a new Node object made with that value. length will be 1 in this case since there is one node in list.

• Create a getListHead method that returns the head of the list

• Create a getListTail method that returns the tail of the list

• Create a getListLength method that returns the length of the list, which is also the number of nodes in the list

• Create a insertAtHead method that takes in a value, creates a new node with that value, and inserts that node before the head node.

  • This should update the head to point at the new node and increment the length of the list.
  • The new node should be updated to point at the previous head.
  • If there was no head, then set the new node to be both the head and the tail
  • Increment length afterwards
  • This method should return this so we can chain methods together such as currLinkedList.insertAtHead(5).insertAtHead(9)

• Create a insertAtTail method that takes in a value, creates a new node with that value, and inserts that node after the tail node.

  • The tail should be updatede to point at the new element.
  • This should update the tail to point at the new node and increment the length of the list.
  • Increment length afterwards
  • This method should return this so we can chain methods together such as currLinkedList.insertAtTail(3).insertAtTail(7)