21. Merge Two Sorted Lists

Posted 2020-10-08 张乐乐章

21. Merge Two Sorted Lists

Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists

 

需要排序！！！

[2,4]
[1]

输出1 2 4

而不是2 4 1 

 

 递归版！！

 1 class Solution {
 2     public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
 3         if(l1==null) return l2;
 4         if(l2==null) return l1;
 5         if(l1.val<l2.val) {
 6             l1.next = mergeTwoLists(l1.next,l2);
 7             return l1;
 8         }
 9         else {
10             l2.next = mergeTwoLists(l2.next,l1);
11             return l2;
12         }
13        
14     }
15     
16 }