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.

题意：旋转链表，k是旋转几位。

思路：对k求余，然后创建头结点，旋转起来。

代码：

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
class Solution {
    public ListNode rotateRight(ListNode head, int k) {
          if (head == null || k == 0) {
            return head;
        }
        int cnt = 1;
        ListNode p2 = head;
        while (p2.next != null) {
            cnt++;
            p2 = p2.next;
        }
        k = k % cnt;
        ListNode pHead = head;
        ListNode p1 = head;
        for (int i = 0; i < cnt - k - 1; i++) {
            p1 = p1.next;
        }
        p2.next = pHead;
        pHead = p1.next;
        p1.next = null;
        return pHead;
    }
}