Partition Linked List

Partition Linked List

class LinkedList
  attr_accessor :head, :tail

  class Node
    attr_accessor :previous, :next, :value

    def initialize(value)
      @value = value
    end
  end


  def inspect

    current = head
    while (current)
      print current.value
      print " >> "
      current = current.next
    end

  end



  def partition(value)

    dummy_1 = Node.new(0)
    dummy_2 =  Node.new(0)

    current_1 = dummy_1
    current_2 = dummy_2

    current = self.head

    while current
      _next = current.next
      current.next = nil
      if current.value < value
        current_1.next = current
        current_1 = current_1.next

      else
        current_2.next = current.clone
        current_2 = current_2.next

      end
      current = _next
    end

    if dummy_1.next
      self.head =  dummy_1.next
      current_1.next = dummy_2.next
    else
      self.head = dummy_2.next
    end


    self
  end
end

l = LinkedList.new
l.head = node1 = LinkedList::Node.new(5)

node1.next = node2 = LinkedList::Node.new(3)
node2.previous = node1

node2.next = node3 = LinkedList::Node.new(1)
node3.previous = node2

node3.next = node4 = LinkedList::Node.new(6)
node4.previous = node3

l.partition(3).inspect