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->nullptr and k = 2, return 4->5->1->2->3->nullptr.
/**
* 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) {
if(head == NULL || k == 0)
return head;
ListNode *p=head;
int len=1;
while(p->next)
{
len++;
p=p->next;
}
p->next = head;
k = len - k%len;
p = head;
for(int i=0; i<k-1; i++)
{
p = p->next;
}
ListNode *newhead = p->next;
p->next = NULL;
return newhead;
}
};