Insert linked list node at nth last position in ruby

Ruby program for Insert linked list node at nth last position. Here problem description and explanation.

#  Ruby program for
#  Insert linked list node at nth last position 

#  Linked list node
class LinkNode 
	# Define the accessor and reader of class LinkNode
	attr_reader :data, :next
	attr_accessor :data, :next
	def initialize(data) 
		self.data = data
		self.next = nil
	end

end

class LinkedList 
	# Define the accessor and reader of class LinkedList
	attr_reader :head
	attr_accessor :head
	def initialize() 
		self.head = nil
	end

	#  insert node at end position
	def insert(value) 
		#  Create a new node
		node = LinkNode.new(value)
		if (self.head == nil) 
			self.head = node
		else
 
			temp = self.head
			#  Find the last node
			while (temp.next != nil) 
				#  Visit to next node
				temp = temp.next
			end

			#  Add node
			temp.next = node
		end

	end

	#  Display linked list element
	def display() 
		if (self.head == nil) 
			return
		end

		temp = self.head
		#  iterating linked list elements
		while (temp != nil) 
			print(temp.data ," → ")
			#  Visit to next node
			temp = temp.next
		end

		print("NULL", "\n")
	end

	#  Add node at specific position from the end of linked list
	def endPosition(position, value) 
		if (self.head == nil) 
			print("Empty Linked list", "\n")
		elsif (position <= 0) 
			print("Invalid position", "\n")
		else
 
			temp = self.head
			location = nil
			while (temp != nil) 
				position -= 1
				if (position <= 0) 
					if (location == nil) 
						location = self.head
					else
 
						location = location.next
					end

				end

				#  visit to next node
				temp = temp.next
			end

			if (position <= 1) 
				node = LinkNode.new(value)
				if (location == nil) 
					#  Add node at first place
					node.next = self.head
					self.head = node
				else
 
					#  Add node at intermediate position
					node.next = location.next
					location.next = node
				end

			else
 
				print("Opps position not found", "\n")
			end

		end

	end

end

def main() 
	sll = LinkedList.new()
	#  Add node
	sll.insert(5)
	sll.insert(4)
	sll.insert(3)
	sll.insert(2)
	sll.insert(1)
	sll.display()
	position = 2
	data = 10
	sll.endPosition(position, data)
	print(" Add ", data ," at last ", 
          position ,"-nd position", "\n")
	sll.display()
end

main()

Output

5 → 4 → 3 → 2 → 1 → NULL
 Add 10 at last 2-nd position
5 → 4 → 3 → 2 → 10 → 1 → NULL


Please share your knowledge to improve code and content standard. Also submit your doubts, and test case. We improve by your feedback. We will try to resolve your query as soon as possible.

New Comment







© 2021, kalkicode.com, All rights reserved