# My python recursion and iteration solution. easy and fast

• Iteration:

``````enter code hereclass Solution(object):
def lowestCommonAncestor(self, root, p, q):
"""
:type root: TreeNode
:type p: TreeNode
:type q: TreeNode
:rtype: TreeNode
"""
while root:
if not root or root==p or root==q:
return root
if self.isnode(p,q):
return p
if self.isnode(q,p):
return q
if self.isnode(root.left,p) and self.isnode(root.left,q):
root=root.left
if self.isnode(root.right,p) and self.isnode(root.right,q):
root=root.right
else:
return root

def isnode(self,mother,child):
if mother:
if mother==child:
return True
else:
return self.isnode(mother.left,child) or self.isnode(mother.right,child)
return False
``````

recursion:

``````enter code hereclass Solution(object):
def lowestCommonAncestor(self, root, p, q):
"""
:type root: TreeNode
:type p: TreeNode
:type q: TreeNode
:rtype: TreeNode
"""

if not root or root==p or root==q:
return root

if self.isnode(p,q):
return p
if self.isnode(q,p):
return q

if self.isnode(root.left,p) and self.isnode(root.left,q):
return self.lowestCommonAncestor(root.left, p, q)
elif self.isnode(root.right,p) and self.isnode(root.right,q):
return self.lowestCommonAncestor(root.right, p, q)
else:
return root

def isnode(self,mother,child):
if mother:
if mother==child:
return True
else:
return self.isnode(mother.left,child) or self.isnode(mother.right,child)
return False``````

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