Java中双链表的查找插入删除

Posted 2022-02-18 Panda_Java

Java中双链表的查找、插入、删除

• 1. Java中双链表

1. Java中双链表

	private void addAfter(Node newNode,Node node)//在某个节点后面添加
		newNode.next = node.next;
		newNode.previous = node;
		newNode.previous.next = newNode;
		newNode.next.previous = newNode;
		++size;
	

package cn.xiaoshan.Collection;
 
import cn.xiaoshan.Collection.MyLinkedList;
import cn.xiaoshan.Collection.MyLinkedList.Node;
 
public class MyLinkedList /*implements List*/
	
	private class Node
 
		private Node previous = this; 
		private Node next = this;
		private Object value;
		Node (Object value)
			this.value = value;
		
		
		public String toString()
			return value.toString();
		
	
	
		private Node head = new Node(null);
	
		private int size;
	
		public int getSize()
		
		return size;
	
 
	
	private boolean addFirst(Object value)//在前面添加
		addAfter(new Node(value),head);
		return true;
	
	private boolean addlast(Object value)//在后面添加
		addBefore(new Node(value),head);
		return true;
	
 
	
	private boolean add(Object value)//默认在后面添加
		addlast(value);
		return true;
	
	private boolean add(int index,Object value)//在指定节点添加，即在指定节点之前添加
		addBefore(new Node(value),getNode(index));
		return true;
	
	private Object getValue(int index)//获得指定位置节点的值
		return getNode(index).value;
	
 
	
	private boolean remove(int index)//移除指定节点
		removeNode(getNode(index));
		return true;
	
	private boolean removeFirst()//删除前面的节点，从第一个节点开始删除
		removeNode(head.next);
		return true;
	
	private boolean removeLast()//删除后面的节点，从最后一个节点开始删除
		removeNode(head.previous);
		return true;
	
	
	
	private Node getNode(int index)//获得指定位置的节点
		if(index<0||index>size)//注意这里判断条件
			throw new IndexOutOfBoundsException("The Index Outof Bounds");
		if(index<size/2)
		Node node = head;
		for(int i = 0;i<=index;i++)
			node = node.next;
		
		return node;
	
	else
		Node node = head;
		for(int i=size-1;i>=index;--i)
			node = node.previous;
		
		return node;
	

	private void addBefore(Node newNode,Node node)//在某个节点前面添加
		newNode.next = node;
		newNode.previous = node.previous;
		newNode.previous.next = newNode;
		newNode.next.previous = newNode;
		size++;
	
	private void addAfter(Node newNode,Node node)//在某个节点后面添加
		newNode.next = node.next;
		newNode.previous = node;
		newNode.previous.next = newNode;
		newNode.next.previous = newNode;
		++size;
	
	private void removeNode(Node node)//删除某个节点
		if(size==0)
		throw new IndexOutOfBoundsException("LinkedList is Empty");
		node.previous.next = node.next;
		node.next.previous = node.previous;
		node.next = null;
		node.previous = null;
		--size;
	
	private boolean isEmpty()
		return size ==0;
	
	
	public String toString()
		StringBuilder str = new StringBuilder(">");
		Node node = head;
		for(int i = 0;i<size;i++)
				node = node.next;
				str.append(node.value);
				str.append(";");
		
		return str.toString();
	
	
	public static void main(String[] args) 
		MyLinkedList link = new MyLinkedList();
		
		link.add(4);
		link.add(7);
		link.add(8);
		System.out.println(link);
		link.addFirst(3);
		link.addFirst(2);
		link.addFirst(1);
		System.out.println(link);
		link.addlast(9);
		link.addlast(10);
		System.out.println(link);
		
		link.add(4, "5");
		link.add(5, 6);
		link.add(0, "在0索引出加上:0");
		System.out.println(link);
		link.add(5, "第5个索引添加后获得这个位置的值");
		System.out.println(link);
		System.out.println(link.getValue(5));
		System.out.println(link.getValue(10));
		System.out.println(link.getValue(11));
//		System.out.println(link.getValue(15));
		
		link.removeFirst();
		System.out.println(link);
		
		link.remove(4);
		System.out.println(link);
		
		System.out.println(link.getSize());
			
		link.removeLast();
		link.removeLast();
		link.removeLast();
		link.removeLast();
		link.removeLast();
		System.out.println(link);
		link.removeLast();
		link.removeLast();
		link.removeLast();
		link.removeLast();
		link.removeLast();
		System.out.println(link);
		link.removeLast();