链表逆序，java实现

 package com.cskaoyan.linkedlist;
 //反转数组
 public class LinkedListDemo2 {
     public static Node reverse(Node head){
         //若输入head是null 或者这个链表只有一个元素,不需要反转
         //null -->null
         //a,null-->a,null
         if(head==null||head.next==null) return head ;
         Node prev=null;
         Node curr=head;
         while(curr!=null){
             Node nextNode=curr.next;
             curr.next=prev;
             prev=curr;
             curr=nextNode;
         }
         return prev;
     }
     //使用递归使链表逆序
     public static Node reverse1(Node head){
         if (head == null || head.next == null) return head;
         Node node=reverse1(head.next);
         head.next.next=head;
         head.next = null;
         return node;
     }
     public static void main(String[] args) {
         Node node = new Node(3);
         node = new Node(2, node);
         node = new Node(1, node);
         Node head = reverse(node);
         System.out.print(head.val + " ");
     }
 }

 package com.cskaoyan.linkedlist;

 public class Node {
     int val;
     Node next;
     public Node(int val){
         this.val=val;
     }
     public Node(int val,Node next){
         this.val=val;
         this.next=next;
     }
 }