Linked List in Ruby
Implement a doubly linked list
exercism fetch ruby linked-list
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 an array-like interface for adding and removing items:
push(insert value at back);
pop(remove value at back);
shift(remove value at front).
unshift(insert value at front);
To keep your implementation simple, the tests will not cover error
shift will never be called on an
If you want to know more about linked lists, check Wikipedia.
For installation and learning resources, refer to the exercism help page.
For running the tests provided, you will need the Minitest gem. Open a terminal window and run the following command to install minitest:
gem install minitest
If you would like color output, you can
require 'minitest/pride' in
the test file, or note the alternative instruction, below, for running
the test file.
Run the tests from the exercise directory using the following command:
To include color from the command line:
ruby -r minitest/pride linked_list_test.rb
Classic computer science topic
Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.