Reverse Linked List II

未完成，还可以找到更好的解

 

 1 /**
 2  * Definition for singly-linked list.
 3  * struct ListNode {
 4  *     int val;
 5  *     ListNode *next;
 6  *     ListNode(int x) : val(x), next(NULL) {}
 7  * };
 8  */
 9 class Solution {
10 public:
11     ListNode *reverseBetween(ListNode *head, int m, int n) {
12         if (m == n)
13             return head;
14             
15         ListNode *before = new ListNode(0);
16         before->next = head;
17         for (int i = 1; i < m; ++i)
18             before = before->next;
19         
20         ListNode *cur = before->next;
21         ListNode *cur_fol = cur->next;
22         ListNode *behind = cur_fol;
23         
24         for (int i = m; i < n; ++i)
25             behind = behind->next;
26         
27         int num = n - m + 1;
28         while (num--) {
29             cur->next = behind;
30             behind = cur;
31             cur = cur_fol;
32             if (cur_fol)
33                 cur_fol = cur_fol->next;
34         }
35         
36         if (m == 1)
37             head = behind;
38         else
39             before->next = behind;
40         
41         return head;
42             
43     }
44 };

 

posted @ 2015-02-11 22:30  胡潇  阅读(161)  评论(0)  编辑  收藏  举报