Add Two Numbers 2

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.

两个链表，反向存储，

2->4->3   代表342

5->6->4  代表465 

相加为    807   7 -> 0 -> 8

注意进位是反向进位，

超大数相加

见到的方法

1）多项式  a1*x^n +a2*x^(n-1) ....ak*x^(k) ....am*x^0

2）链表    两个链表可能不是一样道长度，多余的长度链表直接 拷过去

逆向存储，不用考虑位对齐，首位是个位。。。

特征