1+ /*
2+ Author: King, wangjingui@outlook.com
3+ Date: Dec 13, 2014
4+ Problem: Add Two Numbers
5+ Difficulty: easy
6+ Source: https://oj.leetcode.com/problems/add-two-numbers/
7+ Notes:
8+ You are given two linked lists representing two non-negative numbers.
9+ The digits are stored in reverse order and each of their nodes contain a single digit.
10+ Add the two numbers and return it as a linked list.
11+
12+ Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
13+ Output: 7 -> 0 -> 8
14+
15+ Solution: dummy head...
16+
17+ */
18+ /**
19+ * Definition for singly-linked list.
20+ * public class ListNode {
21+ * int val;
22+ * ListNode next;
23+ * ListNode(int x) {
24+ * val = x;
25+ * next = null;
26+ * }
27+ * }
28+ */
29+ public class Solution {
30+ public ListNode addTwoNumbers (ListNode l1 ,ListNode l2 ) {
31+ ListNode dummy =new ListNode (0 );
32+ ListNode cur =dummy ;
33+ int carry =0 ;
34+ while (l1 !=null ||l2 !=null ||carry !=0 ) {
35+ int sum =carry ;
36+ if (l1 !=null ) {
37+ sum +=l1 .val ;
38+ l1 =l1 .next ;
39+ }
40+ if (l2 !=null ) {
41+ sum +=l2 .val ;
42+ l2 =l2 .next ;
43+ }
44+ carry =sum /10 ;
45+ sum =sum %10 ;
46+ ListNode node =new ListNode (sum );
47+ cur .next =node ;
48+ cur =cur .next ;
49+ }
50+ return dummy .next ;
51+ }
52+ }
