[leetcode #61]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.

需要考虑k大于链表长度，主流的方法是将链表成环然后找到位置然后断环。

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