Branches - Diana Han #26

dhan0406 · 2020-03-02T06:56:28Z

Stacks and Queues

Thanks for doing some brain yoga. You are now submitting this assignment!

Comprehension Questions

Question	Answer
What is an ADT?	Abstract Data Type is a data type that specifies an external interface and it's described by its methods and how they perform. It does not specify how it's build internally or implemented.
Describe a Stack	Stack is an ADT in which elements follow the LIFO rule, last in first out.
What are the 5 methods in Stack and what does each do?	Initialize creates the empty stack class. Push adds an element to the top of the stack. Pop removes and returns the last added element at the top of the stack. Empty? return true is the stack is empty. To_s returns the stack in a string format.
Describe a Queue	Queue is an ADT in which elements follow the FIFO rule, first in first out.
What are the 5 methods in Queue and what does each do?	Initialize creates a queue, in this case the default size was set at 50. Enqueue adds and element to the back of the queue. Dequeue removes and returns the first element. Empty? returns true if the front == back. To_s returns the elements in a string format, after removing the nil spaces.
What is the difference between implementing something and using something?	An example of implementation is how we build the Stack and Queue class creating their methods. Using it would be when we call these methods on data types without knowing HOW it's being done.

OPTIONAL JobSimulation

Question	Answer
Did you include a sample run of your code as a comment?

dhan0406 · 2020-03-06T01:17:31Z

Hi Chris! Can I get more time to revise methods where I'm failing the tests, I can get them done by EOD!

CheezItMan

Nice work, you hit all the learning goals here. Very nice work with the circular buffer.

CheezItMan · 2020-03-10T01:44:34Z

lib/problems.rb

 # Time Complexity: ?
 # Space Complexity: ?
 def balanced(string)


CheezItMan · 2020-03-10T01:44:53Z

lib/queue.rb

-    # @store = ...
-    raise NotImplementedError, "Not yet implemented"
+    @store = Array.new(50)
+    @front = @back = -1
  end

  def enqueue(element)


CheezItMan · 2020-03-10T01:45:33Z

lib/queue.rb

  end

-  def dequeue
-    raise NotImplementedError, "Not yet implemented"
+  def dequeue #remove and return from front


CheezItMan · 2020-03-10T01:46:23Z

lib/queue.rb

  end

  def size
-    raise NotImplementedError, "Not yet implemented"
+    @back - @front


This works when front < back. What about when back has wrapped around the buffer.

CheezItMan · 2020-03-10T01:46:53Z

lib/queue.rb

+    if @front == @back
+      return true
+    end


Suggested change

if @front == @back

return true

end

return @front == @back

CheezItMan · 2020-03-10T01:47:42Z

lib/queue.rb

-    raise NotImplementedError, "Not yet implemented"
+    if @front == @back
+      return true
+    end
  end

  def to_s


👍 Well done

dhan0406 added 4 commits March 1, 2020 19:13

initialized Stack class using Array, passing all Stack tests

bb7934d

initialized Stack class using linked lists

f7e95ca

working through balanced problem

b28e968

implemented queue methods, but unable to pass some tests

19b32be

now passing problem tests

1f686f0

CheezItMan reviewed Mar 10, 2020

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Branches - Diana Han #26

Branches - Diana Han #26

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Branches - Diana Han #26

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Branches - Diana Han #26

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dhan0406 commented Mar 2, 2020

Stacks and Queues

Comprehension Questions

OPTIONAL JobSimulation

dhan0406 commented Mar 6, 2020

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