resolved comments and updated doctests

Author: svedire

data_structures/binary_tree/binary_tree_mirror.py

@@ -1,40 +1,44 @@
-# Created by susmith98
-
-
 """
 Problem Description:
 Given a binary tree, return it's mirror.
 """
 
 
-def binary_tree_mirror_dict(root: int, binary_tree_mirror_dictionary: dict):
+def binary_tree_mirror_dict(binary_tree_mirror_dictionary: dict, root: int):
     if not root or root not in binary_tree_mirror_dictionary:
         return
-    left_child = binary_tree_mirror_dictionary[root][0]
-    right_child = binary_tree_mirror_dictionary[root][1]
+    left_child, right_child = binary_tree_mirror_dictionary[root][:2]
     binary_tree_mirror_dictionary[root] = [right_child, left_child]
-    binary_tree_mirror_dict(left_child, binary_tree_mirror_dictionary)
-    binary_tree_mirror_dict(right_child, binary_tree_mirror_dictionary)
+    binary_tree_mirror_dict(binary_tree_mirror_dictionary, left_child)
+    binary_tree_mirror_dict(binary_tree_mirror_dictionary, right_child)
 
 
-def binary_tree_mirror(binary_tree: dict = {}, root: int = 1) -> dict:
+def binary_tree_mirror(binary_tree: dict, root: int = 1) -> dict:
     """
     >>> binary_tree_mirror({ 1: [2,3], 2: [4,5], 3: [6,7], 7: [8,9]}, 1)
     {1: [3, 2], 2: [5, 4], 3: [7, 6], 7: [9, 8]}
     >>> binary_tree_mirror({ 1: [2,3], 2: [4,5], 3: [6,7], 4: [10,11]}, 1)
     {1: [3, 2], 2: [5, 4], 3: [7, 6], 4: [11, 10]}
+    >>> binary_tree_mirror({ 1: [2,3], 2: [4,5], 3: [6,7], 4: [10,11]}, 5)
+    Traceback (most recent call last):
+    ...
+    ValueError: binary tree cannot be empty
+    >>> binary_tree_mirror({}, 5)
+    Traceback (most recent call last):
+    ...
+    ValueError: root 5 is not present in the binary_tree
     """
     if not binary_tree:
         raise ValueError("binary tree cannot be empty")
     if root not in binary_tree:
-        raise ValueError("root is present in the binary_tree")
+        raise ValueError(f"root {root} is not present in the binary_tree")
     binary_tree_mirror_dictionary = dict(binary_tree)
-    binary_tree_mirror_dict(root, binary_tree_mirror_dictionary)
+    binary_tree_mirror_dict(binary_tree_mirror_dictionary, root)
     return binary_tree_mirror_dictionary
 
 
 if __name__ == "__main__":
     binary_tree = {1: [2, 3], 2: [4, 5], 3: [6, 7], 7: [8, 9]}
-    print("Binary tree: ", binary_tree)
-    binary_tree_mirror_dictionary = binary_tree_mirror(binary_tree, 1)
-    print("Binary tree mirror: ", binary_tree_mirror_dictionary)
+    print(f"Binary tree: {binary_tree}")
+    binary_tree_mirror_dictionary = binary_tree_mirror(binary_tree, 5)
+    print(f"Binary tree mirror: {binary_tree_mirror_dictionary}")