（python）leetcode刷题笔记 02 Add Two Numbers

2. Add Two Numbers

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.

 

 

 

 1 # Definition for singly-linked list.
 2 #class ListNode:
 3 #    def __init__(self, x):
 4 #        self.val = x
 5 #        self.next = None
 6 
 7 class Solution(object):
 8     def addTwoNumbers(self, l1, l2):
 9         """
10         :type l1: ListNode
11         :type l2: ListNode
12         :rtype: ListNode
13         """
14         if l1==None:
15             return l2
16         if l2==None:
17             return l1
18         carry=0
19         s=ListNode(0)
20         ret=s
21         while l1 or l2:#如果两个链表next均不为空
22             sum=0
23             if l1:
24                 sum+=l1.val
25                 l1=l1.next
26             if l2:
27                 sum+=l2.val
28                 l2=l2.next
29             sum+=carry
30             s.next=ListNode(sum%10)
31             s=s.next
32             carry=(sum>=10)
33         if carry==1:
34             s.next=ListNode(1)
35         del s
36         return ret.next
ANSWER

 

posted @ 2018-01-03 19:39  二十四桥明月夜33  阅读(498)  评论(0)  编辑  收藏  举报