javaSE基础之 LinkedList的底层简单实现

Posted 2020-10-04

这里贴上LinkedList底层的简单实现

 

package com.yck.mylinkedlist;

public class Node 
{
    private Node previous; //上一结点
    private Object object; //本结点所存储的东西
    private Node next;    //下一个结点
    
    
    public Node(){}
    
    public Node(Node previous, Object object, Node next)
    {
        super();
        this.previous = previous;
        this.object = object;
        this.next = next;
    }
    
    
    public Node getPrevious() 
    {
        return previous;
    }
    public void setPrevious(Node previous)
    {
        this.previous = previous;
    }
    public Object getObject() 
    {
        return object;
    }
    public void setObject(Object object) 
    {
        this.object = object;
    }
    public Node getNext() 
    {
        return next;
    }
    public void setNext(Node next) 
    {
        this.next = next;
    }
    
    

}

 

package com.yck.mylinkedlist;


/**
 * 手动实现LinkedList底层，这次用了泛型
 * @author Administrator
 *
 * @param <T>
 */
public class MyLinkedList<T>
{
    private Node first;
    private Node last;
    private int size;
    
    
    public MyLinkedList(){}
    
    public void add(T t)
    {
        Node n =new Node();
        if(first == null)
        {
            n.setPrevious(null);
            n.setObject(t);
            n.setNext(null);
            
            first = n;
            last = n;
            size++;
        }
        else
        {
            n.setPrevious(last);
            n.setObject(t);
            n.setNext(null);
            last.setNext(n);
            last = n;
            size++;
        }
        
    }
    public void add(int index,T t)
    {
        rangCheck(index);
        Node temp = new Node();
        if(index == 0)
        {
            temp.setPrevious(null);
            temp.setObject(t);
            temp.setNext(first);
            first = temp;
            
        }
        else if(index != size)
        {
            
            temp.setPrevious(getNode(index-1));
            temp.setObject(t);
            temp.setNext(getNode(index));
            getNode(index-1).setNext(temp);
            getNode(index).setPrevious(temp);
            
        }
        else
        {
            temp.setPrevious(last);
            temp.setObject(t);
            temp.setNext(null);
            last = temp;
        }
        size++;    
    }
    public void add(MyLinkedList<T> list)
    {
        Node temp = new Node();
        temp = list.first;
        temp.setPrevious(this.last);
        this.last.setNext(temp);
        this.last = list.last;
        this.size += list.size;
        list.first.setPrevious(null);
    }
    
    public void remove(int index)
    {
        getNode(index - 1).setNext(getNode(index+1));;
        getNode(index).setPrevious(getNode(index -1));
        size--;
        
    }
    
    
    public Node getNode(int index)
    {
        rangCheck(index);
        Node temp = new Node();
        temp=first;
        for(int i=0;i<index;i++)
        {
            temp=temp.getNext();
        }
        return temp;
    }
    
    
    public Object get(int index)
    {
        return getNode(index).getObject();
    }
    
    
    public void rangCheck(int index)
    {
        if(index<0 || index>=this.size)
            try
        {
                throw new Exception();
        }
        catch (Exception e) 
        {
                // TODO Auto-generated catch block
                e.printStackTrace();
        }
    }
    
    
    public static void main(String[] args)
    {
        MyLinkedList<String> list = new MyLinkedList<String>();
        list.add("aaa");
        list.add("ooo");
        list.add("xxx");
        list.add("fff");
        for(int i=0;i<list.size;i++)
            System.out.println(list.get(i));
        System.out.println("****************");
        
        list.remove(2);
        for(int i=0;i<list.size;i++)
            System.out.println(list.get(i));
        System.out.println("****************");
        
        
        
        
        MyLinkedList<String> list1 = new MyLinkedList<String>();
        list1.add("I");
        list1.add("love");
        list1.add("u");
        System.out.println(list1.first.getPrevious());
        System.out.println("****************");
        
        
        for(int i=0;i<list1.size;i++)
            System.out.println((String)list1.get(i));
        System.out.println("****************");
        
        list.add(list1);
        for(int i=0;i<list.size;i++)
            System.out.println((String)list.get(i));
        System.out.println("****************");
        

        
        
    }

}

 差点忘记贴上面简单测试的结果了