Add Two Numbers.py

'''
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 contains a single digit. Add the two numbers and return the sum as a linked list.

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

 

Example 1:


Input: l1 = [2,4,3], l2 = [5,6,4]
Output: [7,0,8]
Explanation: 342 + 465 = 807.
Example 2:

Input: l1 = [0], l2 = [0]
Output: [0]


'''


class Solution:
    def addTwoNumbers(self, l1, l2 ,c = 0):
        """
        :type l1: ListNode
        :type l2: ListNode
        :rtype: ListNode
        """
        val = l1.val + l2.val + c
        c = val // 10
        ret = ListNode(val % 10 ) 
        
        if (l1.next != None or l2.next != None or c != 0):
            if l1.next == None:
                l1.next = ListNode(0)
            if l2.next == None:
                l2.next = ListNode(0)
            ret.next = self.addTwoNumbers(l1.next,l2.next,c)
        return ret