class Node:

def __init__(self, data):

self.data = data

self.next = None

def newNode(data):

return Node(data)

def reverseList(head):

if not head:

return

curNode = head

prevNode = head

nextNode = head.next

curNode.next = None

while(nextNode):

curNode = nextNode

nextNode = nextNode.next

curNode.next = prevNode

prevNode = curNode

return curNode

def addOne(head):

head = reverseList(head)

k = head

carry = 0

prev = None

head.data += 1

while(head != None) and (head.data > 9 or carry > 0):

prev = head

head.data += carry

carry = head.data // 10

head.data = head.data % 10

head = head.next

if carry > 0:

prev.next = Node(carry)

return reverseList(k)

def printList(head):

if not head:

return

while(head):

print("{}".format(head.data), end="")

head = head.next

if __name__ == '__main__':

head = newNode(1)

head.next = newNode(9)

head.next.next = newNode(9)

head.next.next.next = newNode(9)

print("List is: ", end="")

printList(head)

head = addOne(head)

print("\nResultant list is: ", end="")

printList(head)