# Invert a Binary Tree
# "Google: 90% of our engineers use the software you wrote (Homebrew),
# but you can’t invert a binary tree on a whiteboard so f*** off."
from data_structures.binary_tree import BinaryTree
def solution(root):
if not root:
return root
tmp_node = root.left
root.left = root.right
root.right = tmp_node
solution(root.left)
solution(root.right)
return root
if __name__ == '__main__':
tree = BinaryTree.build_tree_from_list([4, 2, 7, 1, None, 6, 9])
BinaryTree.level_order_traversal(tree.root)
inverted_tree = solution(tree.root)
BinaryTree.level_order_traversal(inverted_tree)
def fail_safe_add(x, y):
if x and y:
return x + y
elif x:
return x
elif y:
return y
else:
return None
def recursive_solution(t1, t2):
if not t1:
return t2
if not t2:
return t1
t1.value = fail_safe_add(t1.value, t2.value)
t1.left = recursive_solution(t1.left, t2.left)
t1.right = recursive_solution(t1.right, t2.right)
return t1
if __name__ == '__main__':
t1 = BinaryTree.build_tree_from_list([1, 3, 2, 5])
t2 = BinaryTree.build_tree_from_list([2, 1, 3, None, 4, 7])
# merged_tree = solution(t1, t2)
# BinaryTree.level_order_traversal(merged_tree.root)
BinaryTree.level_order_traversal(recursive_solution(t1.root, t2.root))
