题解 | #链表内指定区间反转#

import java.util.*;

/*
 * public class ListNode {
 *   int val;
 *   ListNode next = null;
 *   public ListNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param head ListNode类 
     * @param m int整型 
     * @param n int整型 
     * @return ListNode类
     */
    public ListNode reverseBetween (ListNode head, int m, int n) {
        ListNode next = null;
        List<Integer> nodeList = new ArrayList<>();
        while (head != null) {
            nodeList.add(head.val);
            next = head.next;
            head = next;
        }
        List<Integer> nodeListm = nodeList.subList(0, m-1);
        List<Integer> nodeListmn = nodeList.subList(m-1, n);
        List<Integer> nodeListn = nodeList.subList(n, nodeList.size());
        Collections.reverse(nodeListmn);
        nodeList = new ArrayList<>();
        nodeList.addAll(nodeListm);
        nodeList.addAll(nodeListmn);
        nodeList.addAll(nodeListn);
        Collections.reverse(nodeList);
        ListNode resultNode = null;
        for (int i = 0; i < nodeList.size(); i++) {
            ListNode nowNode = new ListNode(nodeList.get(i));
            nowNode.next = resultNode;
            resultNode = nowNode;
        }
        return resultNode;
    }
}