445. Add Two Numbers II

回顾一下，链表：
445. Add Two Numbers II
这个题目，最开始就考虑反转链表，但是题目不允许，我采取了用 栈 把链表里的数取出来的做法。。
后面的做法和 add two numbers 1 差不多了

class ListNode(object):     def __init__(self, x):         self.val = x         self.next = None#445. Add Two Numbers IIclass Solution(object):    def addTwoNumbers(self, l1, l2):        """        :type l1: ListNode        :type l2: ListNode        :rtype: ListNode        """        stack1,stack2=[],[]        while l1:            stack1.append(l1.val)            l1=l1.next        while l2:            stack2.append(l2.val)            l2=l2.next        start=ListNode(0)        carry=0        while stack1 or stack2 or carry:            if stack1:                carry+=stack1.pop()            if stack2:                carry+=stack2.pop()            carry,val=divmod(carry,10)            newnode=ListNode(val)            newnode.next=start.next            start.next=newnode        return start.nextclass Solution(object):     def addTwoNumbers(self, l1, l2):         carry = 0;         res = n = ListNode(0);         while l1 or l2 or carry:             if l1:                 carry += l1.val                 l1 = l1.next;             if l2:                 carry += l2.val;                 l2 = l2.next;             carry, val = divmod(carry, 10)             n.next = n = ListNode(val);         return res.next;