Reverse the Linked List using Recursion

Question

I am using recursion to reverse the linked list but not getting the result. Whenever I am using the following code for the input [1,2,3,4,5,6,-1], it shows me the result [1->None]. I am not getting where I am making the mistake. Please help me.

class Node:
    def __init__(self, data):
        self.data = data
        self.next = None

def takeInput():
    inputList = [int(ele) for ele in input().split()]
    head = None
    for i in inputList:
        if i == -1:
            break
        newNode = Node(i)
        if head is None:
            head = newNode
            tail = newNode
        else:
            tail.next = newNode
            tail = newNode
    return head

def printLL(head):
    while head is not None:
        print(str(head.data) + "->", end="")
        head = head.next 
    print("None")
    return

def reverseLL(head):
    if head is None or head.next is None:
        return head
    rest = reverseLL(head.next)
    head.next.next = head
    head.next = None
    return rest
   

head = takeInput()
printLL(head)
reverseLL(head)
printLL(head)

Answer 1

The problem is in the main code: you're not taking the value returned by the reverseLL function, which is the new head. You should do:

head = reverseLL(head)