反转单向和双向链表简化

 反转单向和双向链表简化:

//反转单向和双向链表public class ReverseList{          //节点的定义    public static class Node{         public int value;         public Node next;                  public Node(int data)          {          this.value=data;          }    }    //反转单向链表    public static Node ReverseOneList(Node head)    {       if(head==null|| head.next==null)       {       return head;       }       Node pre=null;       Node last=null;       while(head!=null)       {       last=head.next;        head.next=pre;       pre=head;       head=last;       }       return pre;    }        //双向链表节点的定义    public static class TNode{     public int value;     public TNode prev,next;     public TNode(int data)     {     this.value=data;     }    }     //反转双向链表    public static TNode ReverseTwoList(TNode head2)    {    while(head2==null||head2.next==null)    {    return head2;    }         TNode pre=null;         TNode last=null;     while(head2!=null)     {     last=head2.next;     head2.next=pre;            head2.prev=pre;     pre=head2;     head2=last;     }     return pre;    }    //打印链表    public static void PrintList(Node head)    {    while(head!=null)    {    System.out.print(head.value+"  ");    head=head.next;    }    System.out.println();    }    //打印双链表    public static void PrintList2(TNode head)    {    while(head!=null)    {    System.out.print(head.value+"  ");    head=head.next;    }    System.out.println();    }public static void main(String []args){         Node node =new Node(1);         node.next =new Node(2);         node.next.next =new Node(3);         //PrintList(node);         Node mode=ReverseOneList(node);         PrintList(mode);         //双向链表的反转         TNode tnode=new TNode(1);          tnode.next=new TNode(2);          tnode.next.next=new TNode(3);          tnode.next.prev=tnode;          tnode.next.next.prev=tnode.next;          //PrintList2(tnode);          TNode t=ReverseTwoList(tnode);          PrintList2(t);   }}