LeetCode21. 合并两个有序链表

将两个升序链表合并为一个新的 升序 链表并返回。新链表是通过拼接给定的两个链表的所有节点组成的。 

示例：

输入：1->2->4, 1->3->4 输出：1->1->2->3->4->4 /** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode() {} * ListNode(int val) { this.val = val; } * ListNode(int val, ListNode next) { this.val = val; this.next = next; } * } */ class Solution { public ListNode mergeTwoLists(ListNode l1, ListNode l2) { ListNode ls = new ListNode(0); ListNode shuai = ls; while(l1 != null && l2 != null){ if(l1.val <= l2.val){ shuai.next = l1; l1 = l1.next; }else{ shuai.next = l2; l2 = l2.next; } shuai = shuai.next; } ListNode o = l1 != null ? l1 : l2; shuai.next = o; return ls.next; } }