if in_iter == 0:
node.data = arr[1]
elif in_iter == l - 1:
node.data = arr[l - 2]
else:
node.data = arr[in_iter - 1] + arr[in_iter + 1]
in_iter += 1
traverse_inorder(node.right, fill_array)
arr: list = []
traverse_inorder(root, fill_array=True)
in_iter = 0
l = len(arr)
traverse_inorder(root, fill_array=False)
return root
if __name__ == "__main__":
root = Node(1)
root.left = Node(2)
root.right = Node(3)
root.left.left = Node(4)
root.left.right = Node(5)
root.right.left = Node(6)
root.right.right = Node(7)
print(inorder(root))
root = replace_data(root)
print(inorder(root))
def full_binary_tree(preorder: list, mirror: list) -> Optional[Node]:
d = {k: v for v, k in enumerate(mirror)}
def tree(start: int, end: int) -> Optional[Node]:
nonlocal pre_index
if start > end or pre_index >= l:
return None
node = Node(preorder[pre_index])
pre_index += 1
if start == end or pre_index >= l:
return node
mirror_index = d[preorder[pre_index]]
if mirror_index <= end:
node.left = tree(mirror_index, end)
node.right = tree(start + 1, mirror_index - 1)
return node
l = len(preorder)
pre_index = 0
return tree(0, l - 1)
if __name__ == "__main__":
print(inorder(full_binary_tree([1, 2, 4, 5, 3, 6, 7], [1, 3, 7, 6, 2, 5, 4])))
nonlocal pre_index
if pre_index >= l or start > end:
return None
value = preorder[pre_index]
node = Node(value)
pre_index += 1
if start == end or pre_index >= l:
return node
post_index: int = d[preorder[pre_index]]
if post_index <= end:
node.left = tree(start, post_index)
node.right = tree(post_index + 1, end)
return node
l = len(preorder)
pre_index = 0
return tree(0, l - 1)
if __name__ == "__main__":
print(
inorder(
full_binary_tree([1, 2, 4, 8, 9, 5, 3, 6, 7],
[8, 9, 4, 5, 2, 6, 7, 3, 1])))
Facts:
1. Full binary tree i.e. 0 or 2 children
2. pre_ln will indicate whether the node has children
time complexity: O(n)
space complexity: O(n) # stack
"""
def tree() -> Optional[Node]:
nonlocal index
if index >= l:
return None
node = Node(preorder[index])
index += 1
if pre_ln[index - 1] == "N":
node.left = tree()
node.right = tree()
return node
index: int = 0
l: int = len(preorder)
return tree()
if __name__ == "__main__":
print(inorder(special_tree([10, 30, 20, 5, 15],
["N", "N", "L", "L", "L"])))
"""
d = {k: v for v, k in enumerate(inorder)}
def tree(start: int, end: int) -> Optional[Node]:
nonlocal pre_index
if pre_index >= l or start > end:
return None
value = preorder[pre_index]
node = Node(value)
in_index = d.get(value) or -1
pre_index += 1
if start < end:
node.left = tree(start, in_index - 1)
node.right = tree(in_index + 1, end)
return node
l: int = len(inorder)
pre_index = 0
return tree(0, l - 1)
if __name__ == "__main__":
inorder(
construct_tree(["D", "B", "E", "A", "F", "C"], ["A", "B", "D", "E", "C", "F"])
)