LeetCode--2. Add Two Numbers--ja

陆陆续续在LeetCode上刷了一些题，一直没有记录过，准备集中整理记录一下

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        ListNode dummy = new ListNode(0);
        ListNode curr = dummy;
        int carry = 0;
        while (l1 != null || l2 != null || carry != 0) {
            int l1_val = (l1 != null)?l1.val:0;
            int l2_val = (l2 != null)?l2.val:0;
            int sum = carry + l1_val + l2_val;
            carry = sum / 10;
            curr.next = new ListNode(sum % 10);
            
            curr = curr.next;
            if (l1 != null) l1 = l1.next;
            if (l2 != null) l2 = l2.next;
        }
        return dummy.next;
    }
}