Created
June 9, 2017 17:09
-
-
Save michellejanosi/d86e880dd275e36df091f309adf4dce3 to your computer and use it in GitHub Desktop.
Linked List 1
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| class LinkedListNode | |
| attr_accessor :value, :next_node | |
| def initialize(value, next_node=nil) | |
| @value = value | |
| @next_node = next_node | |
| end | |
| end | |
| class Stack | |
| attr_reader :data | |
| def initialize | |
| @data = nil | |
| end | |
| # Push a value onto the stack | |
| def push(value) | |
| @data = LinkedListNode.new(value, @data) | |
| end | |
| # Pop an item off the stack. | |
| # Remove the last item that was pushed onto the | |
| # stack and return the value to the user | |
| def pop | |
| # store top node value in a variable | |
| top_node_value = @data.value | |
| # override top node with next node in stack (pop off top value) | |
| @data = @data.next_node | |
| # return top node value | |
| top_node_value | |
| end | |
| end | |
| def print_values(list_node) | |
| if list_node | |
| print "#{list_node.value} --> " | |
| print_values(list_node.next_node) | |
| else | |
| print "nil\n" | |
| return | |
| end | |
| end | |
| def reverse_list(list) | |
| # create stack | |
| stack = Stack.new | |
| # loop through linked list and | |
| while list | |
| # push each node onto the stack | |
| stack.push(list.value) | |
| # move to next node in original linked list | |
| list = list.next_node | |
| end | |
| # return stack | |
| stack.data | |
| end | |
| node1 = LinkedListNode.new(43) | |
| node2 = LinkedListNode.new(109, node1) | |
| node3 = LinkedListNode.new(11, node2) | |
| node4 = LinkedListNode.new(87, node3) | |
| print_values(node4) | |
| revlist = reverse_list(node4) | |
| print_values(revlist) | |
| # => 87 --> 11 --> 109 --> 43 --> nil | |
| # => 43 --> 109 --> 11 --> 87 --> nil |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment