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.
Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
此题和add binary比较类似，只不过不用再考虑数组的高位是num的低位了，代码如下：
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode(int x) { val = x; }
* }
*/
public class Solution {
public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
int carry = 0;
ListNode res = new ListNode(0);
ListNode dummy = res;
while(l1!=null||l2!=null||carry!=0){
if(l1!=null){
carry+=l1.val;
l1 = l1.next;
}
if(l2!=null){
carry+=l2.val;
l2 = l2.next;
}
res.val = carry%10;
carry/=10;
if(l1!=null||l2!=null||carry!=0){
ListNode next = new ListNode(0);
res.next = next;
res = res.next;
}
}
return dummy;
}
}