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.

首先计算链表长度，将链表首尾相接，之后得出链表从head开始起的正向偏移量，从head开始遍历找到旋转后的head,再“扯断”成环的链表，返回新的head.

/** * Definition for singly-linked list. * public class ListNode { *     int val; *     ListNode next; *     ListNode(int x) { *         val = x; *         next = null; *     } * } */public class Solution {    public ListNode rotateRight(ListNode head, int n) {        ListNode p=head;        if(head==null || n==0)return head;        int len=1;        while(p.next!=null)        {            p=p.next;            len++;        }        p.next=head;        n=len-n%len;        while(n>0)        {            p=p.next;            n--;        }        head=p.next;        p.next=null;        return head;    }}