Challenge Rules

Implement a "LinkedList" as described in the previous chapter

The essence of this structure is:

The structure has great performance for access at either end of the list (e.g., methods first, last, addFirst, addLast)
The structure supports adding/removing/inserting elements

No external logic (e.g. "code libraries", etc) is allowed -- that means we will not use the Java library packages (i.e., we will not use the "java.util" package or any others) -- the only exceptions are that the Java package "java.util.function" may be used and the provided method "toArray" uses a couple Java classes as described in its method comment
The grader will expect the provided directory structure be intact (i.e., do not "move" the provided files)

For LinkedList:

In the provided file "DynamicArray.java", replace "//TODO" with your methods and logic
See the comment at the top of LinkedList:.java
The class header is completed for you -- do not modify the header - the grader will expect it exactly as-is (as provided)
The static factory methods are completed for you - the grader will expect those headers be exactly as-is (as provided)
The method "toArray" is completed for you

Data Structures And Algorithms (DSA) (Chapter 402 - Linked List Code Challenge)