Python3 Program to Count rotations in sorted and rotated linked list

# Program for count number of rotations in
# sorted linked list.

# Linked list node 
class Node:
    
    def __init__(self, data):
        
        self.data = data
        self.next = None

# Function that count number of
# rotation in singly linked list.
def countRotation(head):

    # Declare count variable and assign it 1.
    count = 0
 
    # Declare a min variable and assign to
    # data of head node.
    min = head.data
 
    # Check that while head not equal to None.
    while (head != None):
 
        # If min value is greater then head->data
        # then it breaks the while loop and
        # return the value of count.
        if (min > head.data):
            break
 
        count += 1
 
        # head assign the next value of head.
        head = head.next
    
    return count

# Function to push element in linked list.
def push(head, data):

    # Allocate dynamic memory for newNode.
    newNode = Node(data)
 
    # Assign the data into newNode.
    newNode.data = data
 
    # newNode->next assign the address of
    # head node.
    newNode.next = (head)
 
    # newNode become the headNode.
    (head) = newNode
    return head

# Display linked list.
def printList(node):

    while (node != None):
        print(node.data, end = ' ')
        node = node.next
    
# Driver code
if __name__=='__main__':
    
    # Create a node and initialize with None
    head = None
 
    # push() insert node in linked list.
    # 15 -> 18 -> 5 -> 8 -> 11 -> 12
    head = push(head, 12)
    head = push(head, 11)
    head = push(head, 8)
    head = push(head, 5)
    head = push(head, 18)
    head = push(head, 15)
 
    printList(head);
    print()
    print("Linked list rotated elements: ", 
          end = '')
 
    # Function call countRotation()
    print(countRotation(head))

# This code is contributed by rutvik_56