Implementation of Linked List using Ruby

Approach to Create a Linked List

Below Ruby program demonstrates creating a linked list, adding nodes to it, displaying its contents, and removing a node.

Initially ll was created as 1 -> 2 -> 3 -> nil.
Later on, second item in ll whose value is 2 was removed so now ll has become 1 -> 3 -> nil.

Ruby

class Node
  attr_accessor :value, :next_node

  # Initialize a new node with a given value
  def initialize(value)
    @value = value
    
    # Initially, the next node reference is nil
    @next_node = nil  
  end
end

class LinkedList
  
  # Initialize an empty linked list
  def initialize
    
    # Initially, the linked list has no nodes, 
    # so head is nil
    @head = nil  
  end

  # Add a new node with the given value to the 
  # end of the linked list
  def add(value)
    
    # If the linked list is empty
    if @head.nil?  
      
      # Create a new node and set it as the head
      @head = Node.new(value)  
    else
      current = @head
      
      # Traverse the list until the last node
      while current.next_node != nil
        current = current.next_node
      end
      
      # Append the new node to the end of the list
      current.next_node = Node.new(value)
    end
  end

  # Remove the first occurrence of a node with the 
  # given value from the linked list
  def remove(value)
    current = @head
    
    # If the node to be removed is the head
    if current.value == value
      
      # Update head to point to the next node
      @head = current.next_node  
    else
      
      # Traverse the list until the node before 
      # the one to be removed
      while (current.next_node != nil) && 
            (current.next_node.value != value)
        current = current.next_node
      end
      
      # Update the next_node reference to skip 
      # over the node to be removed
      if current.next_node != nil
        current.next_node = current.next_node.next_node
      end
    end
  end

  # Display the values of all nodes in the linked list
  def display
    current = @head
    while current != nil
      print "#{current.value} -> "
      current = current.next_node
    end
    
    # Indicate the end of the list
    puts "nil"  
  end
end

# Example usage:
ll = LinkedList.new
ll.add(1)
ll.add(2)
ll.add(3)
ll.display
ll.remove(2)
ll.display

Output

1 -> 2 -> 3 -> nil
1 -> 3 -> nil

How to Create a Linked List in Ruby?

A linked list is a form of linear data structure whereby the elements are not positioned closely together in memory. Each element here instead points to the subsequent one, thus leading to a chain-like arrangement.

Creating a linked list in Ruby entails defining an information structure where each node has value and link (or reference) to the next node in the sequence. It is also dynamic meaning it can grow or shrink during runtime making it efficient for specific operations such as insertion and deletion.

Tags:

#Ruby

Approach to Create a Linked List

Implementation of Linked List using Ruby

How to Create a Linked List in Ruby?

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