Branches - Brianna #36

brikemp · 2020-03-03T05:59:32Z

Stacks and Queues

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

Comprehension Questions

Question	Answer
What is an ADT?	An abstract data type is a date type that's implementation is independent of its behavior
Describe a Stack	A stack is an ADT that follows the last in-first out rule
What are the 5 methods in Stack and what does each do?	Initialize creates a new instance of the stack class. Push adds an element to the end of the stack. Pop removes the element at the end of the stack. Empty checks to see if there has been any data added to a stack. to_s returns an easily readable string of the data stored in the stack
Describe a Queue	A queue is an ADT that follow the first 9n-first out rule
What are the 5 methods in Queue and what does each do?	Initialize creates a new instance of the queue class. Enqueue adds an element to the end of a queue. Dequeue removes the element at the front of a queue. Size returns the number of items in a queue. Empty check to see whether there is any data in the queue. to_s returns an easily readable string of the data stored in the queue
What is the difference between implementing something and using something?	Implementing something is required before something can be used and allows that instance to access methods specific to it.,

OPTIONAL JobSimulation

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

CheezItMan

Nice work, you hit the main learning goals here. There are some issues with the Queue class. Take a look at my comments and let me know any questions you have.

CheezItMan · 2020-03-10T03:10:06Z

lib/problems.rb

-# Time Complexity: ?
-# Space Complexity: ?
+# Time Complexity: O(n) - n is chars in string
+# Space Complexity: O(1/2n) --> O(n) - n is chars in string
 def balanced(string)


CheezItMan · 2020-03-10T03:10:31Z

lib/problems.rb

 # Time Complexity: ?
 # Space Complexity: ?
 def evaluate_postfix(postfix_expression)


CheezItMan · 2020-03-10T03:13:01Z

lib/queue.rb

  def enqueue(element)
-    raise NotImplementedError, "Not yet implemented"
+    if((@front == 0 && @back == @store.length - 1) || (@front == @back + 1))


It might be better to use `@front == (@back + 1) % @store.length

CheezItMan · 2020-03-10T03:13:23Z

lib/queue.rb

  end
-
+
  def dequeue


CheezItMan · 2020-03-10T03:14:09Z

lib/queue.rb

+      raise ArgumentError
+    end
+
+    return @back - @front


This only works if @front < @back,

Suggested change

return @back - @front

return @back - @front if @front < @back

return @back + @store.length - @front

CheezItMan · 2020-03-10T03:15:04Z

lib/queue.rb

+    if @front == -1 && @back == -1
+      return true
+    else
+      return false
+    end


Suggested change

if @front == -1 && @back == -1

return true

else

return false

end

return @front == -1 && @back == -1

CheezItMan · 2020-03-10T03:15:15Z

lib/queue.rb

  def to_s
-    return @store.to_s
+    return @store[@front...@back].to_s


Again this only works if front < back.

CheezItMan · 2020-03-10T03:15:46Z

lib/queue.rb

+# q = Queue.new
+# q.enqueue(0)
+# q.enqueue(1)
+# q.enqueue(2)
+# q.enqueue(3)
+# p q
+# p q.size
+# p q.dequeue
+# p q.size
+# p q.front


This should probably be removed before submission

Suggested change

# q = Queue.new

# q.enqueue(0)

# q.enqueue(1)

# q.enqueue(2)

# q.enqueue(3)

# p q

# p q.size

# p q.dequeue

# p q.size

# p q.front

Brianna Kemp and others added 5 commits March 2, 2020 19:14

Initial set up

64b28e3

Wave 1 complete

0e89da5

Wave 2 complete

844b54c

Wave 3 complete

a6d3078

Completed optional

41a61e6

CheezItMan reviewed Mar 10, 2020

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Branches - Brianna #36

Branches - Brianna #36

brikemp commented Mar 3, 2020 •

edited

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CheezItMan Mar 10, 2020

CheezItMan Mar 10, 2020

	return @back - @front
	return @back - @front if @front < @back
	return @back + @store.length - @front

Branches - Brianna #36

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brikemp commented Mar 3, 2020 • edited Loading

Stacks and Queues

Comprehension Questions

OPTIONAL JobSimulation

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brikemp commented Mar 3, 2020 •

edited

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