java实现单链表

早上清早起来，第一件事就是打开博客园随便的翻看下博客， 看到有篇文章提到的算法数据结构，实现一个单链表的操作。作者是使用c#编写的， 那么我这里通过java也来弄弄。

首先定义一个Node类

public class Node {

     protected Node next; //指针域  

     public  int data;//数据域  

       

     public Node( int data) {  

           this. data = data;  

     }  

       

     //显示此节点  

     public void display() {  

          System. out.print( data + " ");  

     }  

}

接下来定义一个单链表，并实现相关方法：

public class LinkList {

    public Node first; // 定义一个头结点

    private int pos = 0;// 节点的位置



    public LinkList() {

        this.first = null;

    }



    // 插入一个头节点

    public void addFirstNode(int data) {

        Node node = new Node(data);

        node.next = first;

        first = node;

    }



    // 删除一个头结点,并返回头结点

    public Node deleteFirstNode() {

        Node tempNode = first;

        first = tempNode.next;

        return tempNode;

    }



    // 在任意位置插入节点 在index的后面插入

    public void add(int index, int data) {

        Node node = new Node(data);

        Node current = first;

        Node previous = first;

        while (pos != index) {

            previous = current;

            current = current.next;

            pos++;

        }

        node.next = current;

        previous.next = node;

        pos = 0;

    }



    // 删除任意位置的节点

    public Node deleteByPos(int index) {

        Node current = first;

        Node previous = first;

        while (pos != index) {

            pos++;

            previous = current;

            current = current.next;

        }

        if (current == first) {

            first = first.next;

        } else {

            pos = 0;

            previous.next = current.next;

        }

        return current;

    }



    // 根据节点的data删除节点(仅仅删除第一个)

    public Node deleteByData(int data) {

        Node current = first;

        Node previous = first; // 记住上一个节点

        while (current.data != data) {

            if (current.next == null) {

                return null;

            }

            previous = current;

            current = current.next;

        }

        if (current == first) {

            first = first.next;

        } else {

            previous.next = current.next;

        }

        return current;

    }



    // 显示出所有的节点信息

    public void displayAllNodes() {

        Node current = first;

        while (current != null) {

            current.display();

            current = current.next;

        }

        System.out.println();

    }



    // 根据位置查找节点信息

    public Node findByPos(int index) {

        Node current = first;

        if (pos != index) {

            current = current.next;

            pos++;

        }

        return current;

    }



    // 根据数据查找节点信息

    public Node findByData(int data) {

        Node current = first;

        while (current.data != data) {

            if (current.next == null)

                return null;

            current = current.next;

        }

        return current;

    }

}

最后我们可以通过测试类来做相关测试:

public class TestLinkList {

    public static void main(String[] args) {  

        LinkList linkList = new LinkList();  

        linkList.addFirstNode(20);  

        linkList.addFirstNode(21);  

        linkList.addFirstNode(19);  

         //print19,21,20  

        linkList.add(1, 22); //print19,22,21,20  

        linkList.add(2, 23); //print19,22,23,21,20  

        linkList.add(3, 99); //print19,22,23,99,21,20  

      //调用此方法会print 19,22,23,99,21,20 

        linkList.displayAllNodes();  

        }

}

至此，对单链表的操作就笔记到这里了。