interactive-coding-challenges/graphs_trees/binary_tree/binary_search_tree.py

class Node (object):
	def __init__ (self, data):
		self.data = data
		self.rightChild = None
		self.leftChild = None

class BinaryTree (object):
	def __init__ (self):
		self.root = None

	def insert (self, newData):
		leaf = Node(newData)

		if self.root is None:
			self.root = leaf
		else:
			current = self.root
			parent = self.root
			while current is not None:
				parent = current
				if newData < current.data:
					current = current.leftChild
				else:
					current = current.rightChild

			if newData < parent.data:
				parent.leftChild = leaf
			else:
				parent.rightChild = leaf

	# returns false if the item to be deleted is not on the tree
	def delete (self, data):
		current = self.root
		parent = self.root
		isLeft = False

		if current is None:
			return False

		while current is not None and current.data is not data:
			parent = current
			if data < current.data:
				current = current.leftChild
				isLeft = True 
			else:
				current = current.rightChild
				isLeft = False

		if current is None:
			return False

		if current.leftChild is None and current.rightChild is None:
			if current is self.root:
				self.root = None
			elif isLeft:
				parent.leftChild = None
			else:
				parent.rightChild = None

		elif current.rightChild is None:
			if current is self.root:
				self.root = current.leftChild
			elif isLeft:
				parent.leftChild = current.leftChild
			else:
				parent.rightChild = current.leftChild

		elif current.rightChild is None:
			if current is self.root:
				self.root = current.rightChild
			elif isLeft:
				parent.lChild = current.rightChild
			else:
				parent.rightChild = current.rightChild

		else:
			succesor = current.rightChild
			succesorParent = current

			while succesor.leftChild is not None:
				succesorParent = succesor
				succesor = succesor.leftChild

			if current is self.root:
				self.root = succesor
			elif isLeft:
				parent.leftChild = succesor
			else:
				parent.rightChild = succesor

			succesor.leftChild = current.leftChild

			if succesor is not current.rightChild:
				succesorParent.leftChild = succesor.rightChild
				succesor.rightChild = current.rightChild

		return True 


	def minNode (self):
		current = self.root
		while current.leftChild is not None:
			current = current.leftChild

		return current.data

	def maxNode (self):
		current = self.root
		while current.rightChild is not None:
			current = current.rightChild

		return current.data

	def printPostOrder (self):
		global postOrder
		postOrder = []

		def PostOrder(node):
			if node is not None:
				PostOrder(node.leftChild)
				PostOrder(node.rightChild)
				postOrder.append(node.data)

		PostOrder(self.root)
		return postOrder

	def printInOrder (self):
		global inOrder 
		inOrder = []

		def InOrder (node):
			if node is not None:
				InOrder(node.leftChild)
				inOrder.append(node.data)
				InOrder(node.rightChild)

		InOrder(self.root)
		return inOrder

	def printPreOrder (self):
		global preOrder
		preOrder = []

		def PreOrder (node):
			if node is not None:
				preOrder.append(node.data)
				PreOrder(node.leftChild)
				PreOrder(node.rightChild)

		PreOrder(self.root)
		return preOrder

	def treeIsEmpty (self):
		return self.root is None