Amy P #18

aphunk · 2019-10-01T04:32:19Z

Heaps Practice

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Question	Answer
How is a Heap different from a Binary Search Tree?	Binary search trees guarantee an order based on the values of the nodes while heaps only guarantee that the parent is larger (max-heap) or that the child is larger (min-heap).
Could you build a heap with linked nodes?	Yes
Why is adding a node to a heap an O(log n) operation?	The maximum number of operations is determined by the height of the tree, and not the number of nodes.
Were the `heap_up` & `heap_down` methods useful? Why?	Yes, they were very useful in the add and remove methods--keeping heap up and down private made the add/remove methods more readable.

CheezItMan

Definitely some issues here. Take a look at my comments and let me know if you have questions.

CheezItMan · 2019-10-04T22:17:10Z

lib/heap_sort.rb

+  end
+
+  sorted = []
+  heap.each do |elem|


Heaps don't have a .each method.

Suggested change

heap.each do |elem|

while !heap.empty?

CheezItMan · 2019-10-04T22:19:08Z

lib/heap_sort.rb

+
+  sorted = []
+  heap.each do |elem|
+    sorted << heap.remove(elem)


remove doesn't take an argument.

CheezItMan · 2019-10-04T22:19:17Z

lib/min_heap.rb

+  # Time Complexity: O(log n), where n is the number of nodes in heap
+  # Space Complexity: O(log n), where n is the number of nodes in heap


CheezItMan · 2019-10-04T22:19:55Z

lib/min_heap.rb

-  # Time Complexity: ?
-  # Space Complexity: ?
+  # Time Complexity: O(log n), where n is the number of nodes in heap
+  # Space Complexity: O(1)


Since heap_down is recursive, you will be using the call stack, so the space complexity is O(log n)

aphunk added 2 commits September 30, 2019 20:55

complete methods & pass tests

f588ab2

add heapsort method, pass test

e39052c

CheezItMan reviewed Oct 4, 2019

View reviewed changes

		# Time Complexity: O(log n), where n is the number of nodes in heap
		# Space Complexity: O(log n), where n is the number of nodes in heap