return left
elif right:
return right
return None
def findLowestAnsestorBST(root, n1, n2):
if root is None:
return None
else:
if root.data > n1 and root.data > n2:
findLowestAnsestorBST(root.left, n1, n2)
elif root.data < n1 and root.data < n2:
findLowestAnsestor(root.right, n1, n2)
return root
if __name__ == '__main__':
root = TreeNode(1)
root.left = TreeNode(2)
root.right = TreeNode(3)
root.left.left = TreeNode(4)
root.left.right = TreeNode(5)
root.right.left = TreeNode(6)
root.right.right = TreeNode(7)
print "LCA(4, 5) = ", findLowestAnsestor(root, 4, 5)
print "LCA(4, 6) = ", findLowestAnsestor(root, 4, 6)
print "LCA(3, 4) = ", findLowestAnsestor(root, 3, 4)
print "LCA(2, 4) = ", findLowestAnsestor(root, 2, 4)
