Add Two Numbers – Leetcode Solution

You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4 )
Output: 7 -> 0 -> 8
Explanation: 342 + 465 = 807

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def addTwoNumbers(self, l1, l2):
        """
        :type l1: ListNode
        :type l2: ListNode
        :rtype: ListNode
        """
        newList = ListNode(self)
        temp = newList
        
        carry =0
        sumTotal = 0
        
        while l1 or l2 or carry:
            if l1:
                sumTotal =  sumTotal+ l1.val
                l1 = l1.next
            if l2:
                sumTotal = sumTotal + l2.val
                l2 = l2.next
            sumTotal = sumTotal + carry
            carry  = sumTotal//10
            temp.next = ListNode(sumTotal%10)
            sumTotal = 0
            temp  = temp.next
        
        return newList.next