【LeetCode】Add Two Numbers

题目地址：https://oj.leetcode.com/problems/add-two-numbers/

链表遍历，注意最高位不为0的情况，同时L1和L2都为null的出现

/** * Definition for singly-linked list. * public class ListNode { *     int val; *     ListNode next; *     ListNode(int x) { *         val = x; *         next = null; *     } * } */public class Solution {    public ListNode addTwoNumbers(ListNode l1, ListNode l2) {int tmp=0;int count=0;ListNode head=null;ListNode pre =null;while(true){if(l1!=null||l2!=null||tmp>0){count++;if(l1!=null)tmp+=l1.val;if(l2!=null)tmp+=l2.val;if(count==1){head=new ListNode(tmp%10);pre=head;}else{ListNode node=new ListNode(tmp%10);pre.next=node;pre=pre.next;}tmp=tmp/10;if(l1!=null)l1=l1.next;if(l2!=null)l2=l2.next;}if(l1==null&&l2==null&&tmp==0){break;}        }return head;    }}