Reverse Linked List II

来源：Leetcode

原帖：http://oj.leetcode.com/problems/reverse-linked-list-ii/

题目：
Reverse a linked list from position m to n. Do it in-place and in one-pass.
For example:
Given 1->2->3->4->5->NULL, m = 2 and n = 4, return 1->4->3->2->5->NULL.
Note:
Given m, n satisfy the following condition:
1 <= m <= n <= length of list.

代码：

 class Solution {  
 public:  
     ListNode *reverseBetween(ListNode *head, int m, int n) {  
         ListNode dummy(0);  
         dummy.next = head;  
         head = &dummy;    
         for (int i = 0; i < m - 1; ++i) {  
             head = head->next;  
         }  
         ListNode *cur = head->next;  
         for (int i = 0; i < n - m; ++i) {  
             ListNode *move = cur->next;  
             cur->next = move->next;  
             move->next = head->next;  
             head->next = move;  
         }  
         return dummy.next;  
     }  
 };