【LeetCode OJ 061】Rotate List

【LeetCode OJ 061】Rotate List

題目：Given a list, rotate the list to the right bykplaces, wherekis non-negative.

For example:
Given1->2->3->4->5->NULLandk=2,
return4->5->1->2->3->NULL.

解題思路：題意為給定一個鏈表，要求按照給定的位置進行反轉。示例代碼如下：

public class Solution
{
	  public ListNode rotateRight(ListNode head, int k) 
	  {
		if (head == null)
			return null;
		ListNode p = head;
		ListNode q = head;
		int num = 1;//統計鏈表元素個數
		while (p.next != null)
		{
			num++;
			p = p.next;//p指向尾節點
		}
		int n = 1;
		if (k >= num)
			k = k % num;//處理循環反轉的情況
		while (n < num - k)
		{
			n++;
			q = q.next;
		}
		ListNode h = null;
		if (q.next != null)
		{
			//將q後面的節點作為新的頭結點
			h = q.next;
			q.next = null;
			p.next = head;
		} 
		else
		{
			h = head;
		}
		return h;

	  }
}