Rotate List

-----QUESTION-----

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.

-----SOLUTION-----

class Solution {public:    ListNode *rotateRight(ListNode *head, int k) {        if(!head) return head;                ListNode *p = head;        ListNode *newHead;        int num = 1;        while(p->next)        {            p = p->next;            num++;        }        k = k%num;        if(k==0) return head;        p->next = head;        p = head;        for(int i = 0; i<num-k-1; i++)        {            p = p->next;        }        head = p->next;        p->next = NULL;        return head;    }};