反转从位置 m 到 n 的链表。请使用一趟扫描完成反转。

说明:
1 ≤ m ≤ n ≤ 链表长度。

示例:
输入: 1->2->3->4->5->NULL, m = 2, n = 4
输出: 1->4->3->2->5->NULL

想的很混乱,后面还要再看看!!
参考https://note.youdao.com/ynoteshare1/index.html?id=383f28fda2c91ea9736e71a189c80718&type=note这位大神的笔记

public ListNode reverseBetween(ListNode head, int m, int n) {

		ListNode dummyNode = new ListNode(-1);
		dummyNode.next = head;

		ListNode pre = dummyNode;
		ListNode cur = head;
		ListNode mNode = null;
		ListNode nNode = null;
		ListNode mPre = null;
		ListNode nNext = null;

		int index = 1;
		//寻找m点
		while (cur!=null && index<m){
			pre = cur;
			cur = cur.next;
			index++;
		}
		mNode = cur;
		mPre = pre;

		//寻找n点
		while (cur!=null && index<=n){
			ListNode next = cur.next;
			cur.next = pre;
			pre = cur;
			cur = next;
			index++;
		}
		nNode = pre;
		nNext = cur;
		mPre.next = nNode;
		if (mNode!=null){
			mNode.next = nNext;
		}

		return dummyNode.next;
	}