2. Add Two Numbers 两个数字相加

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.

Example

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

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# 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         """         node1, node2 = l1, l2         newList = newNode = ListNode(0)         carry = 0         while node1 or node2 or carry:             v1, v2 = 0, 0             if node1:                 v1, node1 = node1.val, node1.next             if node2:                 v2, node2 = node2.val, node2.next               val = (v1 + v2 + carry)             carry = 1 if val >= 10 else 0             newNode.next = ListNode(val % 10)             newNode = newNode.next         return newList.next

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