[LeetCode61]Rotate List

 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* rotateRight(ListNode* head, int k) {
12         if(!head)
13             return head;
14         int length = 1;
15         ListNode *newHead, *tail;
16         newHead = tail = head;
17         //得到结点数
18         while(tail->next)
19         {
20             tail = tail->next;
21             length++;
22         }
23         //构造一个换
24         tail->next = head;
25         
26         if(k %= length)
27         {
28             for(int i = 0; i < length - k; ++i)
29                 tail = tail->next;
30         }
31         newHead = tail->next;
32         tail->next = NULL;
33         return newHead;
34     }
35 };