Add Two Numbers - LeetCode

Add Two Numbers - LeetCode

题目：

You are given two linked lists representing two non-negative numbers. 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.

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8

分析：

这道题目就是简单的两个列表值相加，不过要考虑两条列表长度不同和进位规则，即{5}和{5}相加，结果为{1,，0}。代码由于自我水平问题感觉长度较大。

代码：

class Solution:
    # @return a ListNode
    def addTwoNumbers(self, l1, l2):
        l3 = ListNode(0)
        l = l3 
        flag = 0
        while l1 or l2:
            if l1 and l2:
               temp = ListNode(l1.val + l2.val+flag)
               l1,l2 = l1.next,l2.next
            elif l1 and not l2:
               temp = ListNode(l1.val+flag)
               l1 = l1.next
            elif l2 and not l1:
               temp = ListNode(l2.val+flag)
               l2 = l2.next
            l3.next = temp
            if l3.next.val<10:
                flag = 0  
            elif l3.next.val>=10:
                flag = 1
                l3.next.val = l3.next.val%10
            l3 = l3.next
        if flag == 1:
            l3.next = ListNode(1)
        return l.next