class BinarySearchTree:
def __init__(self):
self.root=None
self.size=0
def length(self):
return self.size
def __len__(self):
return self.size
def __iter__(self):
return self.root.__iter__()
def __setitem__(self,k,v):
self.put(k,v)
def put(self,key,val):
if self.root:
self._put(key,val,self.root)
else:
self.root=TreeNode(key,val)
self.size=self.size+1
def _put(self,key,val,currentNode):#has a bug
if key<currentNode.key:
if currentNode.hasLeftChild():
self._put(key,val,currentNode.leftChild)
else:
currentNode.leftChild=TreeNode(key,val,parent=currentNode)
else:
if currentNode.hasRightChild():
self._put(key,val,currentNode.rightChild)
else:
currentNode.rightChild=TreeNode(key,val,parent=currentNode)
def get(self,key):
if self.root:
res=self._get(key,self.root)
if res:
return res.payload
else:
return None
else:
return None
def _get(self,key,currentNode):
if not currentNode:
return None
elif currentNode.key==key:
return currentNode
elif key<currentNode.key:
return self._get(key,currentNode.leftChild)
else:
return self._get(key,currentNode.rightChild)
def __getitem__(self,key):
return self.get(key)
def __contains__(self,key):
if self._get(key,self.root):
return True
else:
return False
def delete(self,key):
if self.size>1:
nodeToRemove=self._get(key,self.root)
if nodeToRemove:
self.remove(nodeToRemove)
self.size=self.size-1
else:
raise KeyError('Error,key not in tree')
elif self.size ==1 and self.root.key==key:
self.root=None
self.size=self.size-1
else:
raise KeyError('Error,key not in tree')
def __delitem__(self,key):
self.delete(key)
def spliceOut(self):
if self.isLeaf():
if self.isLeftChild():
self.parent.leftChild=None
else:
self.parent.rightChild=None
elif self.hasAnyChildren():
if self.hasLeftChild():
if self.isLeftChild():
self.parent.leftChild=self.leftChild
else:
self.parent.rightChild=self.leftChild
self.leftChild.parent=self.parent
else:
if self.isLeftChild():
self.parent.leftChild=self.rightChild
else:
self.parent.rightChild=self.rightChild
self.rightChild.parent=self.parent
def findSuccessor(self):
succ=None
if self.hasRightChild():
succ=self.rightChild.findMin()
else:
if self.parent:
if self.isLeftChild():
succ=self.parent
else:
self.parent.rightChild=None
succ=self.parent.findSuccessor()
self.parent.rightChild=self
return succ
def findMin(self):
current=self
while current.hasLeftChild():
current=current.leftChild
return current
def __iter__(self):
if self:
if self.hasLeftChild():
for elem in self.leftChild:
yield elem
yield self.key
if self.hasRightChild():
for elem in self.rightChild:
yield elem
def remove(self,currentNode):
if currentNode.isLeaf():
if currentNode == currentNode.parent.leftChild:
currentNode.parent.leftChild=None
else:
currentNode.parent.rightChild=None
elif currentNode.hasBothChildren():
succ=currentNode.findSuccessor()
succ.spliceOut()
currentNode.key=succ.key
currentNode.payload=succ.payload
else:
if currentNode.hasLeftChild():
if currentNode.isLeftChild():
currentNode.leftChild.parent=currentNode.parent
currentNode.parent.leftChild=currentNode.leftChild
elif currentNode.isRightChild():
currentNode.leftChild.parent = currentNode.parent
currentNode.parent.rightChild = currentNode.leftChild
else:
currentNode.replaceNodeData(currentNode.leftChild.key,
currentNode.leftChild.payload,
currentNode.leftChild.leftChild,
currentNode.leftChild.rightChild)
else:
if currentNode.isLeftChild():
currentNode.rightChild.parent = currentNode.parent
currentNode.parent.leftChild = currentNode.rightChild
elif currentNode.isRightChild():
currentNode.rightChild.parent = currentNode.parent
currentNode.parent.rightChild = currentNode.rightChild
else:
currentNode.replaceNodeData(currentNode.rightChild.key,
currentNode.rightChild.payload,
currentNode.rightChild.leftChild,
currentNode.rightChild.rightChild)
class TreeNode:
def __init__(self,key,val,left=None,right=None,parent=None):
self.key=key
self.payload=val
self.leftChild=left
self.rightChild=right
self.parent=parent
def hasLeftChild(self):
return self.leftChild
def hasRightChild(self):
return self.rightChild
def isLeftChild(self):
return self.parent and self.parent.leftChild == self
def isRightChild(self):
return self.parent and self.parent.rightChild == self
def isRoot(self):
return not self.parent
def isLeaf(self):
return not (self.rightChild or self.leftChild)
def hasAnyChildren(self):
return self.rightChild or self.leftChild
def hasBothChildren(self):
return self.rightChild and self.leftChild
def replaceNodeData(self,key,value,lc,rc):
self.key=key
self.payload=value
self.leftChild=lc
self.rightChild=rc
if self.hasLeftChild():
self.leftChild.parent=self
if self.hasRightChild():
self.rightChild.parent=self
mytree = BinarySearchTree()
mytree[3]="red"
mytree[4]="blue"
mytree[6]="yellow"
mytree[2]="at"
print(mytree[6])
print(mytree[2])
