LeetCode: Merge Two Sorted Lists 解题报告

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.

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SOLUTION 1:

使用dummynode记录头节点的前一个，轻松完成，2分钟就AC啦！

 1 /**

 2  * Definition for singly-linked list.

 3  * public class ListNode {

 4  *     int val;

 5  *     ListNode next;

 6  *     ListNode(int x) {

 7  *         val = x;

 8  *         next = null;

 9  *     }

10  * }

11  */

12 public class Solution {

13     public ListNode mergeTwoLists(ListNode l1, ListNode l2) {

14         ListNode dummy = new ListNode(0);

15         ListNode cur = dummy;

16         

17         while (l1 != null && l2 != null) {

18             if (l1.val < l2.val) {

19                 cur.next = l1;

20                 l1 = l1.next;

21             } else {

22                 cur.next = l2;

23                 l2 = l2.next;

24             }

25             cur = cur.next;

26         }

27         

28         if (l1 != null) {

29             cur.next = l1;

30         } else {

31             cur.next = l2;

32         }

33         

34         return dummy.next;

35     }

36 }

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GITHUB:

https://github.com/yuzhangcmu/LeetCode_algorithm/blob/master/list/MergeTwoLists_1206.java