"""

Check if two nodes are cousin or not

Condition for being cousin -

1. Level is same

2. They are not siblings

"""

class Node:

def __init__(self, val):

self.val = val

self.left = None

self.right = None

def level(root, node, lev):

if not root:

return 0

if root == node:

return lev

l = level(root.left, node, lev+1)

if not l == 0:

return l

l = level(root.right, node, lev+1)

def is_sibling(root, a, b):

if not root:

return False

return (root.left == a and root.right == b) or \

(root.right == b and root.left == a) or \

is_sibling(root.left, a, b) or \

is_sibling(root.right, a, b)

def is_cousin(root, a, b):

if level(root, a, 1) == level(root, b, 1) and not is_sibling(root, a, b):

return True

else:

return False

root = Node(1)

root.left = Node(2)

root.right = Node(3)

root.left.left = Node(4)

root.left.right = Node(5)

root.left.right.right = Node(15)

root.right.left = Node(6)

root.right.right = Node(7)

root.right.left.right = Node(8)

node1 = root.left.right

node2 = root.right.right

print(is_cousin(root, node1, node2))