LeetCode 61 Rotate List

题目链接：Rotate List
题意：将链表向右滚动，超出末尾的链接在头部

依旧是考验细节的题，第一次遍历的时候记录下长度，第二次历遍根据移动的距离得到移动后的链表的头结点和尾结点，再处理下引用关系即可。

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

        while (x.next != null) {
            x = x.next;
            len++;
        }
        x.next = head;
        k = k % len;
        while (k++ < len)
            x = x.next;

        ListNode last = x;
        ListNode first = x.next;

        last.next = null;
        return first;
    }
}