Class: LinkedList::Doubly

Inherits:
Object
  • Object
show all
Defined in:
lib/data_struct/linked_list.rb

Overview

This is a Doubly linked list implementation.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Doubly

Returns a new instance of Doubly.



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# File 'lib/data_struct/linked_list.rb', line 126

def initialize
  @head = nil
  @length = 0
end

Instance Attribute Details

#head ⇒ Object (readonly)

Returns the value of attribute head.



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# File 'lib/data_struct/linked_list.rb', line 125

def head
  @head
end

#length ⇒ Object (readonly)

Returns the value of attribute length.



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# File 'lib/data_struct/linked_list.rb', line 125

def length
  @length
end

Instance Method Details

#each ⇒ Object 



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# File 'lib/data_struct/linked_list.rb', line 187

def each
  node = @head
  arr = []
  @length.times do
    arr << yield(node.data)
    node = node.next_val
  end
  arr
end

#index(index_val) ⇒ Object 



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# File 'lib/data_struct/linked_list.rb', line 197

def index(index_val)
  raise 'index value higher than current length of list' if @length - 1 < index_val

  node = @head
  index_val.times do
    node = node.next_val
  end
  node.data
end

#index_of(val) ⇒ Object 



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# File 'lib/data_struct/linked_list.rb', line 207

def index_of(val)
  node = @head
  @length.times do
    return node.data if node.data == val

    node = node.next_val
  end
  raise 'value not found'
end

#pop ⇒ Object 



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# File 'lib/data_struct/linked_list.rb', line 152

def pop
  node = @head
  if @length.zero?
    raise 'Error: List is empty'
  else
    de_length
    (@length - 1).times do
      node = node.next_val
    end
    node.next_val = nil
  end

  @head
end

#push(val) ⇒ Object 



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# File 'lib/data_struct/linked_list.rb', line 140

def push(val)
  in_length
  return @head = DoublyNode.new(val) if @head.nil?

  node = @head
  (@length - 2).times do
    node = node.next_val
  end
  node.next_val = DoublyNode.new val
  node.next_val.pre_val = node
end

#to_a ⇒ Object 



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# File 'lib/data_struct/linked_list.rb', line 177

def to_a
  node = @head
  arr = []
  @length.times do
    arr << node.data
    node = node.next_val
  end
  arr
end

#to_s ⇒ Object 



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# File 'lib/data_struct/linked_list.rb', line 167

def to_s
  node = @head
  str = ''
  (@length - 1).times do
    str += "#{node.data} "
    node = node.next_val
  end
  str
end

#unshift(val) ⇒ Object 



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# File 'lib/data_struct/linked_list.rb', line 131

def unshift(val)
  in_length
  return @head = DoublyNode.new(val) if @head.nil?

  new_head = DoublyNode.new val, nil, @head
  @head.pre_val = new_head
  @head = new_head
end