LeetCode_Rotate List

Given a list, rotate the list to the right by k places, where k is non-negative.



For example:

Given 1->2->3->4->5->NULL and k = 2,

return 4->5->1->2->3->NULL.

　　巨没劲的一道题，当k>length 时，我以为origin list 不动就行，结果好些case过不了，看了别人的代码才知道要 k%= length 真心想不通为什么，也懒得弄这种恶心的东西。面试遇到这种题目直接问面试官这种奇葩情况怎么处理就行。 

/**

 * Definition for singly-linked list.

 * struct ListNode {

 *     int val;

 *     ListNode *next;

 *     ListNode(int x) : val(x), next(NULL) {}

 * };

 */

class Solution {

public:

    ListNode *rotateRight(ListNode *head, int k) {

        // Start typing your C/C++ solution below

        // DO NOT write int main() function

        if(head == NULL || k == 0) return head;

		ListNode *p, *q;

		p = head;q= p;

		while(q &&--k){

			q = q->next;

		}

		if(k >0 || NULL == q) return head; 

		ListNode *pre = NULL;

		

		while(q->next){

			pre = p;

			p = p->next;

			q = q->next;

		}

		q ->next = head;

		head  = p;

		pre ->next = NULL;

		return head;

		

    }

};