Algorithms—61.Rotate List

思路：找到断点，打断拼接。

/** * 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) {return head;}        ListNode l=head;        List<ListNode> list=new ArrayList<ListNode>();        while (l!=null) {list.add(l);l=l.next;}        k=k%list.size();        if (k==0) {return head;}        list.get(list.size()-k-1).next=null;        list.get(list.size()-1).next=head;    return list.get(list.size()-k);    }}

耗时：324ms，中上游