Insertion Sort List

Sort a linked list using insertion sort.

 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 insertionSortList(ListNode head) {

14         // IMPORTANT: Please reset any member data you declared, as

15         // the same Solution instance will be reused for each test case.

16         ListNode header = new ListNode(-1);

17         header.next = null;

18         if(head == null) return header.next;

19         ListNode cur = head;

20         while(cur != null){

21             ListNode tmp = header.next;

22             ListNode before = header;

23             while(tmp != null && tmp.val < cur.val){

24                 before = before.next;

25                 tmp = tmp.next;

26             }

27             before.next = cur;

28             ListNode a = cur.next;

29             cur.next = tmp;

30             cur = a;

31         }

32         return header.next;

33     }

34 }

 第二遍：

 1 public class Solution {

 2     public ListNode insertionSortList(ListNode head) {

 3         // IMPORTANT: Please reset any member data you declared, as

 4         // the same Solution instance will be reused for each test case.

 5         if(head == null) return head;

 6         ListNode header = new ListNode(-1);

 7         ListNode cur = head, newbefore = header;

 8         while(cur != null){

 9             newbefore = header;

10             while(newbefore.next != null && newbefore.next.val < cur.val){

11                 newbefore = newbefore.next;

12             }

13             ListNode newcur = newbefore.next;

14             newbefore.next = cur;

15             ListNode tmp = cur.next;

16             cur.next = newcur;

17             cur = tmp;

18         }

19         return header.next;

20     }

21 }