screening interview: queue using restricted size arrays

solution.rb

# Build a queue class with the enqueue and dequeue methods.
# The queue can store an *UNLIMITED* number of elements but you are limited to using arrays that can store up to 5 elements max
# 1# [3,4,5] 2# [6,7,8,9,10] 3# [11,12,13]
# [1#, 2#, 3#, 4#, 5#] [6#, ]

class Node
    SIZE_LIMIT = 5.freeze
    
    attr_accessor :value
    attr_accessor :_next
    attr_accessor :size
    
    def initialize
        @value = []
        @_next = nil
        @size = 0
    end
    
    def insert(val)
        return false if @value.size == SIZE_LIMIT
        @value << val
        @size  += 1
        return true  
    end
    
    def get_element()
        return [ @value.shift, @_next ]
    end
end

class Queue
    attr_accessor :head
    attr_accessor :tail
    
    def initialize()
        @head = Node.new
        @tail = @head
    end
    
    def dequeue()
        result = @head.get_element
        element = result[0]
        _next = result[1]
        while !element && _next
            @head = @head._next
            result = @head.get_element
            element = result[0]
            _next = result[1]
        end
        puts element
        return element
    end
    
    
    def enqueue(val)
        result = @tail.insert(val)
        unless result
           @tail._next = Node.new
           @tail = @tail._next
           @tail.insert(val) 
        end
    end
end

q = Queue.new()
q.enqueue(1) # => true
q.enqueue(2) # => true
q.enqueue(3) # => true
q.enqueue(4) # => true
q.enqueue(5) # => true
q.enqueue(6) # => true
q.dequeue()# => 1
q.dequeue() # => 2
q.dequeue() # => 3
q.dequeue() # => 4
q.dequeue() # => 5
q.dequeue() # => 6
q.dequeue() # => nil