Class: LinkedList

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/bibliogem/LinkedList.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(value = nil) ⇒ LinkedList

Returns a new instance of LinkedList.



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# File 'lib/bibliogem/LinkedList.rb', line 9

def initialize(value=nil)
	@head = Node.new(nil, value, nil)
end

Instance Attribute Details

#head ⇒ Object (readonly)

Returns the value of attribute head.



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# File 'lib/bibliogem/LinkedList.rb', line 7

def head
  @head
end

Instance Method Details

#each ⇒ Object 



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# File 'lib/bibliogem/LinkedList.rb', line 98

def each
	current = @head
	until current == nil
		yield (current[:value])
		current=current[:next]
	end
end

#erase(position) ⇒ Object 



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# File 'lib/bibliogem/LinkedList.rb', line 54

def erase(position)
	if position > size
		return nil
	end
	if position == 0
		if @head[:next].nil?
			@head = nil
		else
			@head = @head[:next]
		end
	else
		current = @head
		for i in 0..position-1
			current = current[:next]
		end
		current = current[:prev]
		current[:next] = (current[:next])[:next]
	end
end

#insert(position, *values) ⇒ Object 



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# File 'lib/bibliogem/LinkedList.rb', line 37

def insert(position, *values)
	current = @head
	if position == 0
		for value in values.reverse
			@head = Node.new(nil, value, @head)
		end
	else
		for i in 1..position-1
			current = current[:next]
		end
		for value in values.reverse
			current[:next] = Node.new(current, value, current[:next])
		end
	end
	self
end

#pop_back ⇒ Object 



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# File 'lib/bibliogem/LinkedList.rb', line 21

def pop_back
	current = @head
	until current[:next] == nil
		current = current[:next]
	end
	aux = current[:value]
	erase(size-1)
	return aux
end

#pop_front ⇒ Object 



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# File 'lib/bibliogem/LinkedList.rb', line 31

def pop_front
	aux = @head[:value]
	erase(0)
	return aux
end

#push_back(value) ⇒ Object 



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# File 'lib/bibliogem/LinkedList.rb', line 13

def push_back value
	insert(size, value)
end

#push_front(value) ⇒ Object 



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# File 'lib/bibliogem/LinkedList.rb', line 17

def push_front value
	insert(0, value)
end

#size ⇒ Object 



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# File 'lib/bibliogem/LinkedList.rb', line 74

def size
	if @head == nil or @head[:value] == nil
		return 0
	end
	counter = 1
	current = @head
	until current[:next] == nil
		counter+=1
		current=current[:next]
	end
	counter
end

#to_s ⇒ Object 



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# File 'lib/bibliogem/LinkedList.rb', line 87

def to_s
	current = @head
	to_s_array = []
	until current[:next] == nil
		to_s_array.push(current[:value])
		current=current[:next]
	end
	to_s_array.push(current[:value])
	p "[#{to_s_array.join(', ')}]"
end