LeetCode——Rotate List，leetcoderotate

LeetCode——Rotate List，leetcoderotate

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.

原題連結：https://oj.leetcode.com/problems/rotate-list/

得到鏈表長度，鏈表指向尾節點，將鏈表首尾相連，向右k%len，得到結果鏈表的尾節點。

public class RotateList {public static void main(String[] args) {ListNode head = new ListNode(1);ListNode head1 = new ListNode(2);ListNode head2 = new ListNode(3);ListNode head3 = new ListNode(4);ListNode head4 = new ListNode(5);head.next = head1;head1.next = head2;head2.next = head3;head3.next = head4;//while(head != null){//System.out.println(head.val);//head = head.next;//}ListNode ln = new RotateList().rotateRight(head, 2);while(ln != null){System.out.println(ln.val);ln = ln.next;}}public ListNode rotateRight(ListNode head, int n) {if(head == null)return head;int len = 1;ListNode tmp = head;while(tmp.next != null){tmp = tmp.next;len ++;}tmp.next = head;n %= len;int step = len - n;while(step > 0){tmp = tmp.next;step --;}head = tmp.next;tmp.next = null;return head;}}// Definition for singly-linked list. class ListNode {int val;ListNode next;ListNode(int x) {val = x;next = null;}}