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
.
start with an example.
Given [0,1,2]
, rotate 1 steps to the right -> [2,0,1]
.
Given [0,1,2]
, rotate 2 steps to the right -> [1,2,0]
.
Given [0,1,2]
, rotate 3 steps to the right -> [0,1,2]
.
Given [0,1,2]
, rotate 4 steps to the right -> [2,0,1]
.
So, no matter how big K, the number of steps is, the result is always the same as rotating K % n
steps to the right.
public class Solution { public ListNode rotateRight(ListNode head, int n) { if(head==null||head.next==null||n==0) return head; int len = 0; ListNode root = head; while(root!=null){ root=root.next; len++; } ListNode fast = head; ListNode slow = head; int i=n%len; if(i==0) return head; while(i>0&&fast!=null){ fast=fast.next; i--; } while(fast.next!=null){ slow=slow.next; fast=fast.next; } ListNode tem = slow.next; fast.next=head; slow.next=null; return tem; } }