445. 两数相加 II

工程之美

什么样的工程是美的:

1. 可维护
2. 可读性
3. 可扩展性

如果链表的长度不是特别恐怖的情况下, 这个栈的方案是非常有价值的.
易懂是第一点, 有了问题也能及时排查到.

使用栈来解决问题

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

class Solution(object):
    def addTwoNumbers(self, l1, l2):
        """
        :type l1: ListNode
        :type l2: ListNode
        :rtype: ListNode
        """
        n1 = []
        n2 = []
        while l1:
            n1.append(l1.val)
            l1 = l1.next
        while l2:
            n2.append(l2.val)
            l2 = l2.next
        count = 0
        result = []
        while n1 or n2 or count:
            a = n1.pop() if n1 else 0
            b = n2.pop() if n2 else 0
        
            sum = a + b + count
        
            if sum<10:
                result.append(sum)
                count = 0
            else:
                result.append(sum-10)
                count = 1
            
        res = ListNode(0)
        r = res
        for i in result[::-1]:
            r.next = ListNode(i)
            r = r.next
        return res.next