binary search tree implementation

graphs_trees/binary_tree/binary_search_tree.py

@@ -0,0 +1,155 @@
+
+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