Question

In python I want to create a function that takes in a linked list. Using recursion only, I want to check if the linked list is sorted. How do i do this?

Answer 1

# Python program to check Linked List is sorted
# in descending order or not
''' Linked list Node '''

class Node:
   def __init__(self, data):
       self.data = data;
       self.next = next;

# function to Check Linked List is
# sorted in descending order or not
def isSortedDesc(head):
   if (head == None):
       return True;

   # Traverse the list till last Node and return
   # False if a Node is smaller than or equal
   # its next.
   while(head.next != None):
       t = head;
       if (t.data <= t.next.data):
           return False;
       head = head.next
   return True;

def newNode(data):
   temp = Node(0);
   temp.next = None;
   temp.data = data;
   return temp;

# Driver Code
if __name__ == '__main__':
   head = newNode(7);
   head.next = newNode(5);
   head.next.next = newNode(4);
   head.next.next.next = newNode(3);

   if (isSortedDesc(head)):
       print("Yes");
   else:
       print("No");