003 | java实现单链表

写在前面：熟能生巧，古人诚不欺我！

1. 结点类

package list;

/**
 * Create by IDEA
 * User: zhangqi
 * Date: 2019/2/26
 * Desc: 单链表结点
 */
public class LinkNode {

    //指针域
    LinkNode next;

    //数据域
    Object data;

    /**
     * 初始化头结点
     * @param head
     */
    public LinkNode(LinkNode head) {
        this.next = head;
    }

    /**
     * 初始化元素结点
     * @param head
     * @param data
     */
    public LinkNode(LinkNode head, Object data) {
        this.next = head;
        this.data = data;
    }

    public LinkNode getNext() {
        return next;
    }

    public void setNext(LinkNode next) {
        this.next = next;
    }

    public Object getData() {
        return data;
    }

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

    @Override
    public String toString() {
        return data.toString();
    }
}

2. 单链表抽象数据类型

package list;

/**
 * Create by IDEA
 * User: zhangqi
 * Date: 2019/2/26
 * Desc: 单链表抽象数据类型
 */
public interface SimpleLink {

    /**
     * 获取链表长度
     * @return
     */
    int size();

    /**
     * 判断链表是否为空
     * @return
     */
    boolean isEmpty();

    /**
     * 获取结点数据
     * @param index
     * @return
     */
    Object getNodedata(int index) throws Exception;

    /**
     * 删掉结点
     * @param index
     */
    void deleteNode(int index) throws Exception;

    /**
     * 插入结点
     * @param index
     */
    void insertNode(int index, Object data) throws Exception;
}

3. 单链表实现类

package list;

/**
 * Create by IDEA
 * User: zhangqi
 * Date: 2019/2/26
 * Desc: 单链表实现类
 */
public class SimpleLinkImpl implements SimpleLink {

    //链表长度
    int size;

    //头指针
    LinkNode head;

    //当前结点
    LinkNode current;

    /** 初始化一个空链表，此时当前结点就是头结点，链表长度为0 */
    public SimpleLinkImpl() {
        /**
         * 此时当前结点和头结点重合，不能使用以下方式进行初始化
         * this.head = new LinkNode(null); this.current = new LinkNode(null);
         */
        this.head = current = new LinkNode(null);
        this.size = 0;
    }

    /**
     * 获取要操作结点位置，首元素结点下标为0，则假设头结点下标为-1
     * @param index
     * @throws Exception
     */
    public void location(int index) throws Exception {
        /** 大于链表长度或者在头结点之前 */
        if (index < -1 || index > size-1) throw new Exception("输入索引有误");

        /** 表示插入或者删除第一个元素结点 */
        if(index == -1) return;
        current = head.next;
        int j = 0;
        while (current != null && j < index) {
            current = current.next;
            j++;
        }
    }

    @Override
    public int size() {
        return size;
    }

    @Override
    public boolean isEmpty() {
        return size == 0;
    }

    @Override
    public Object getNodedata(int index) throws Exception {
        location(index);
        return current.getData();
    }

    @Override
    public void deleteNode(int index) throws Exception {
        if (isEmpty()) {
            throw new Exception("链表为空，无法删除！");
        }
        if (index < 0 || index > size) {
            throw new Exception("参数有误！");
        }
        /** 定位到要操作结点的前一个结点 */
        location(index-1);
        current.setNext(current.next.next);
        size--;
    }

    @Override
    public void insertNode(int index, Object data) throws Exception {
        if (index < 0 || index > size) {
            throw new Exception("参数有误！");
        }
        /** 定位到要操作结点的前一个结点 */
        location(index-1);
        current.setNext(new LinkNode(current.next,data));
        size++;
    }
}

4. 测试单链表

package list;

import java.util.Random;

/**
 * Create by IDEA
 * User: zhangqi
 * Date: 2019/2/26
 * Desc:
 */
public class SimpleLinkTest {

    public static void main(String[] args) throws Exception {
        SimpleLinkImpl link = new SimpleLinkImpl();
        for(int i=0;i<10;i++) {
            Random random = new Random();
            int num = random.nextInt(100);
            link.insertNode(i,num);
            System.out.print(num + "  ");
        }
        System.out.println("SIZE: "+link.size());
        link.deleteNode(4);
        for(int j=0;j<link.size();j++) {
            System.out.print(link.getNodedata(j) + "  ");
        }
        System.out.println("SIZE: "+link.size());
    }
}

5. 测试结果
   

https://www.cnblogs.com/smyhvae/p/4761593.html，感谢这位博主，感谢！