Implement a doubly linked list.

Like an array, a linked list is a simple linear data structure. Several common data types can be implemented using linked lists, like queues, stacks, and associative arrays.

A linked list is a collection of data elements called nodes. In a singly linked list each node holds a value and a link to the next node. In a doubly linked list each node also holds a link to the previous node.

You will write an implementation of a doubly linked list. Implement a Node to hold a value and pointers to the next and previous nodes. Then implement a List which holds references to the first and last node and offers functions for adding and removing items.

Your Node should have the following fields and functions:

• Val: the node's value (we will use interface{}).
• Next(): pointer to the next node.
• Prev(): pointer to the previous node.
• First(): pointer to the first node (head).
• Last(): pointer to the last node (tail).

Your List should have the following fields and functions:

• First(): pointer to the first node (head).
• Last(): pointer to the last node (tail).
• PushBack(v interface{}): insert value at back.
• PopBack() (interface{}, error): remove value at back.
• PushFront(v interface{}) : remove value at front.
• PopFront() (interface{}, error): insert value at front.
• Reverse(): reverse the linked list.

Instead of not covering error conditions, like calling PopBack or PopFront on an empty list, we will follow Go's idiomatic style and implement the error checks as well.

If you want to know more about linked lists, check Wikipedia.

To run the tests run the command go test from within the exercise directory.

If the test suite contains benchmarks, you can run these with the -bench flag:

go test -bench .

Keep in mind that each reviewer will run benchmarks on a different machine, with different specs, so the results from these benchmark tests may vary.

If you are not familar with linked list, try this tutorial.

Classic CS data structure.

It's possible to submit an incomplete solution so you can see how others have completed the exercise.