Two Lists Sum Advanced
最后更新于：2022-04-02 01:10:24
# Two Lists Sum Advanced
### Source
- CC150 - [Add two numbers represented by linked lists | Set 2 - GeeksforGeeks](http://www.geeksforgeeks.org/sum-of-two-linked-lists/)
~~~
Given two numbers represented by two linked lists, write a function that returns sum list.
The sum list is linked list representation of addition of two input numbers.
Example
Input:
First List: 5->6->3 // represents number 563
Second List: 8->4->2 // represents number 842
Output
Resultant list: 1->4->0->5 // represents number 1405
Challenge
Not allowed to modify the lists.
Not allowed to use explicit extra space.
~~~
### 题解1 - 反转链表
在题 [Two Lists Sum | Data Structure and Algorithm](http://algorithm.yuanbin.me/zh-cn/linked_list/two_lists_sum.html) 的基础上改了下数位的表示方式，前者低位在前，高位在后，这个题的高位在前，低位在后。很自然地可以联想到先将链表反转，而后再使用 Two Lists Sum 的解法。
### Reference
- [Add two numbers represented by linked lists | Set 2 - GeeksforGeeks](http://www.geeksforgeeks.org/sum-of-two-linked-lists/)
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