题解 | #反转链表#

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
     * @return ListNode类
     */
    public ListNode ReverseList(ListNode head) {
        // write code here
	  //如果为空返回空
        if (head == null) return null;
        //初始化为空
        ListNode myList = null;

        while (head!= null) {
		  //临时节点存储除去head头后的链表
            ListNode temp = head.next;
		  //将head头节点安装到myList
            head.next = myList;
		  //head头节点与原链表断开后接到myList
            myList = head;
		  //head头节点重新回归原链表
            head = temp;

        }

        return myList;
    }
}