def get_max(current: BinaryTreeNode):
"""
This method returns the maximum value in a BST.
:param current: The current node.
:return: The maximum value in the BST
"""
while current.has_right():
current = current.get_right()
return current.get_data()
def post_order(current: BinaryTreeNode, result: list):
"""
This method implements the Depth First - Post-order Traversal of a Binary Tree.
:param current: The current node in the tree.
:param result: The list to collect the result of the traversal.
"""
if current is None:
return
BinaryTreeTraversal.post_order(current.get_left(), result)
BinaryTreeTraversal.post_order(current.get_right(), result)
result.append(current.get_data())
def search(self, current: BinaryTreeNode, search_target):
"""
This method tells whether a given data point is there in the BST.
:param current: The current node.
:param search_target: The data to be searched.
:return: The boolean flag whether the data is present.
"""
if current is None:
return False
elif current.get_data() == search_target:
return True
elif search_target <= current.get_data():
return self.search(current.get_left(), search_target)
else:
return self.search(current.get_right(), search_target)
def is_bst(current: BinaryTreeNode,
min_val=float("-inf"),
max_val=float("inf")):
"""
This method checks whether a given Binary Tree is a BST.
:param current: The current node.
:param min_val: The minimum value which should be less than or equal to the current node data to be a BST.
:param max_val: The maximum value which should be greater than or equal to the current node data to be a BST.
:return: The boolean flag indicating whether the given Binary Tree is a BST.
"""
if current is None:
return True
if (min_val <= current.get_data() <= max_val
and BinarySearchTree.is_bst(current.get_left(), min_val,
current.get_data())
and BinarySearchTree.is_bst(current.get_right(),
current.get_data(), max_val)):
return True
return False
def level_order(current: BinaryTreeNode, result: list):
"""
This method implements the Breadth First - Level Order Traversal of a Binary Tree.
:param current: The current node in the tree.
:param result: The list to collect the result of the traversal.
"""
if current is None:
return
queue = Queues()
queue.enqueue(current)
while not queue.is_empty():
current = queue.de_queue()
result.append(current.get_data())
if current.has_left():
queue.enqueue(current.get_left())
if current.has_right():
queue.enqueue(current.get_right())
def insert(self,
current: BinaryTreeNode,
data,
parent=None,
add_parent=False):
"""
This method inserts a new data node in the BST using recursion.
:param current: The current node.
:param data: The data to be inserted.
:param parent: The parent for the new node.
:param add_parent: The flag to add parent.
:return: The tree with the new data node.
"""
if current is None:
return BinaryTreeNode(data, parent=parent)
elif data <= current.get_data():
current.set_left(
self.insert(current.get_left(), data, current, add_parent))
elif current.get_data() < data:
current.set_right(
self.insert(current.get_right(), data, current, add_parent))
return current
def remove(self, current: BinaryTreeNode, to_remove):
"""
This method removes the data node from the BST if the data is present.
todo - how to update parents?
:param current: The current node.
:param to_remove: The data to be removed from BST.
:return: The updated current node.
"""
if current is None:
return current
elif to_remove < current.get_data():
current.set_left(self.remove(current.get_left(), to_remove))
elif current.get_data() < to_remove:
current.set_right(self.remove(current.get_right(), to_remove))
else:
if not current.has_left() and not current.has_right():
current = None
elif not current.has_left():
current = current.get_right()
elif not current.has_right():
current = current.get_left()
else:
current.set_data(self.get_min(current.get_right()))
current.set_right(
self.remove(current.get_right(), current.get_data()))
return current