反转单链表

ListNode是单链表节点的数据结构，实现见如下代码：package List;

/** * Created by Administrator on 2015/10/10. */public class ListNode {    //节点的值    private char data;    //节点的后续节点    private ListNode next;

    public ListNode(char data, ListNode next) {        this.data = data;        this.next = next;    }    public ListNode(ListNode next){        this.next=next;    }

    public char getData() {        return data;    }

    public void setData(char data) {        this.data = data;    }

    public ListNode getNext() {        return next;    }

    public void setNext(ListNode next) {        this.next = next;    }}那么对于链表的反转操作及其测试用例如下：

package List;

/** * Created by Administrator on 2015/10/10. */public class NodeUtil {    public static void printList(ListNode head){        if(head.getNext()==null){            System.out.println("此链表为空！");        }else{           ListNode p=head.getNext();           while (p.getNext()!=null){               System.out.print(p.getData()+"->");               p=p.getNext();           }        System.out.print(p.getData());        }

    }    //反转链表    public static ListNode reverseLinkedList(ListNode head){        ListNode p=head.getNext();        ListNode q=p.getNext();        p.setNext(null);        while (q.getNext()!=null){            ListNode nextQ=q.getNext();            q.setNext(p);            p=q;            q=nextQ;        }        q.setNext(p);        ListNode root=new ListNode(q);        return root;    }    //测试    public static void main(String[] args){        ListNode D=new ListNode(‘D‘,null);        ListNode C=new ListNode(‘C‘,D);        ListNode B=new ListNode(‘B‘,C);        ListNode A=new ListNode(‘A‘,B);        ListNode head=new ListNode(A);        System.out.println("反转链表之前");        printList(head);        System.out.println();        System.out.println("反转链表之后");        ListNode root=reverseLinkedList(head);        printList(root);    }}