Python Program For Comparing Two Strings Represented As Linked Lists

# Python program to compare two strings 
# represented as linked lists

# A linked list node 
# structure
class Node:

    # Constructor to create 
    # a new node
    def __init__(self, key):
        self.c = key ; 
        self.next = None

def compare(list1, list2):
    
    # Traverse both lists. Stop when 
    # either end of linked list is 
    # reached or current characters 
    # don't match
    while(list1 and list2 and 
          list1.c == list2.c):
        list1 = list1.next 
        list2 = list2.next 

    # If both lists are not empty, 
    # compare mismatching characters 
    if(list1 and list2):
        return 1 if list1.c > list2.c else -1 

    # If either of the two lists has 
    # reached end
    if (list1 and not list2):
        return 1 

    if (list2 and not list1):
        return -1 
    return 0

# Driver code
list1 = Node('g')
list1.next = Node('e')
list1.next.next = Node('e')
list1.next.next.next = Node('k')
list1.next.next.next.next = Node('s')
list1.next.next.next.next.next = Node('b')

list2 = Node('g')
list2.next = Node('e')
list2.next.next = Node('e')
list2.next.next.next = Node('k')
list2.next.next.next.next = Node('s')
list2.next.next.next.next.next = Node('a')

print compare(list1, list2)
# This code is contributed by Nikhil Kumar Singh(nickzuck_007)