Added doctest to heap.py

data_structures/heap/heap.py

@@ -53,7 +53,37 @@ def __repr__(self) -> str:
  return str(self.h)
 
  def parent_index(self, child_idx: int) -> int | None:
- """return the parent index of given child"""
+ """
+ returns the parent index based on the given child index
+
+ >>> h = Heap()
+ >>> h.build_max_heap([103, 9, 1, 7, 11, 15, 25, 201, 209, 107, 5])
+ >>> h
+ [209, 201, 25, 103, 107, 15, 1, 9, 7, 11, 5]
+
+ >>> h.parent_index(-1) # returns none if index is <=0
+
+ >>> h.parent_index(0) # returns none if index is <=0
+
+ >>> h.parent_index(1)
+ 0
+ >>> h.parent_index(2)
+ 0
+ >>> h.parent_index(3)
+ 1
+ >>> h.parent_index(4)
+ 1
+ >>> h.parent_index(5)
+ 2
+ >>> h.parent_index(10.5)
+ 4.0
+ >>> h.parent_index(209.0)
+ 104.0
+ >>> h.parent_index("Test")
+ Traceback (most recent call last):
+ ...
+ TypeError: '>' not supported between instances of 'str' and 'int'
+ """
  if child_idx > 0:
  return (child_idx - 1) // 2
  return None