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.

题目含义：从列表的末尾依次翻转k个元素到头部

 1     public ListNode rotateRight(ListNode head, int k) {
 2         if (head==null||head.next==null) return head;
 3         ListNode dummy=new ListNode(0);
 4         dummy.next=head;
 5         ListNode fast=dummy,slow=dummy;
 6         int length=0;
 7         while (fast.next!=null)
 8         {
 9             length++;
10             fast = fast.next;
11         }
12         for (int j=length-k%length;j>0;j--) //Get the i-n%i th node
13             slow=slow.next;
14         fast.next=dummy.next; //Do the rotation
15         dummy.next=slow.next;
16         slow.next=null;
17         return dummy.next;     
18     }

 

posted @ 2017-10-24 16:56  daniel456  阅读(72)  评论(0)  编辑  收藏  举报