java数据结构之链表(2)

白天贴了一个链表的数据结构，基本上都是看着书写的，晚上自己动手写了一个，这里贴出来给大家砸鸡蛋哈，

1，链表节点

package pku.ss.datastructure.ILinkedList;


public interface ILinkedList {
	/**
	 * get the size of the list
	 * @return the size of the list
	 */
	public int getSize();
	/**
	 * Judge that if the list is empty
	 * @return true or false
	 */
	public boolean isEmpty();
	/**
	 * make the list empty
	 */
	public void makeEmpty();
	/**
	 * Judge that if the list contains the node whose element equals x
	 * @param x
	 * @return true or false
	 */
	public boolean contains(Object x);
	/**
	 * remove the node whose element equals x, and return a 
	 * boolean value that if there is a x in list then return true,
	 * else return false
	 * @param x
	 * @return true or false
	 */
	public boolean remove(Object x);
	/**
	 * Insert a node behind k'st into list with node's element equals x
	 * @param x
	 * @param k
	 * @return true or false
	 */
	public boolean insert(Object x, int k);
	/**
	 * get the first element of list
	 * @return element of the first node
	 */
	public Object getFirst();
	/**
	 * get the last element of list
	 * @return element of the last node
	 */
	public Object getLast();
	/**
	 * print the elements of the list
	 */
	public void printList();
}

2,链表结构

package pku.ss.datastructure.LinkedList;

import pku.ss.datastructure.ILinkedList.ILinkedList;

public class LinkedList implements ILinkedList {
	private int size;
	private ListNode header;

	/**
	 * Initialize a list with max capability of 0
	 * 
	 * @param size
	 */
	public LinkedList() {
		this.size = 0;
		header = new ListNode(null);
	}

	@Override
	public boolean contains(Object x) {
		if (size == 0) {
			System.out.println("The list is empty!");
			return false;
		}
		ListNode temp = header.next;
		while (temp != null && !temp.element.equals(x))
			temp = temp.next;
		if (temp == null)
			return false;
		else
			return true;
	}

	@Override
	public Object getFirst() {
		if (size == 0) {
			System.out.println("The list is empty");
			return null;
		}
		return header.next.element;
	}

	@Override
	public Object getLast() {
		if (size == 0) {
			System.out.println("The list is empty");
			return null;
		}
		ListNode temp = header.next;
		while (temp.next != null)
			temp = temp.next;
		return temp.element;
	}

	@Override
	public int getSize() {
		return this.size;
	}

	public boolean insert(Object x) {
		return insert(x, 0);
	}

	@Override
	public boolean insert(Object x, int k) {
		if (size < k)
			return false;
		int count = 0;
		ListNode temp = header;
		while (count < k && temp.next != null) {
			temp = temp.next;
			count++;
		}
		ListNode aNode = new ListNode(x);
		aNode.next = temp.next;
		temp.next = aNode;
		size++;
		return true;
	}

	@Override
	public boolean isEmpty() {
		if (size != 0)
			return false;
		else
			return true;
	}

	@Override
	public void makeEmpty() {
		header = null;
		size = 0;
	}

	@Override
	public boolean remove(Object x) {
		if (!contains(x))
			return false;
		ListNode temp = header;
		while (temp.next != null && !temp.next.element.equals(x))
			temp = temp.next;
		temp.next = temp.next.next;
		size--;
		return true;
	}

	public void printList() {
		if (size == 0)
			System.out.println("The list is Empty");
		else {
			ListNode temp = header.next;
			while (temp != null) {
				System.out.print(temp.element + " ");
				temp = temp.next;
			}
		}
		System.out.println();
		System.out.println("***************************");
	}
}

3，测试类

package pku.ss.datastructure.Demo;

import pku.ss.datastructure.LinkedList.LinkedList;

public class LinkedListDemo {
	public static void main(String[] args) {
		LinkedList list = new LinkedList();
		list.insert("H");
		list.insert("G");
		list.insert("F");
		list.insert("E");
		list.insert("D");
		list.insert("C");
		list.insert("B");
		list.insert("A");

		list.printList();

		list.remove("A");

		list.printList();

		list.insert("D1", 3);
		list.printList();
		if (list.isEmpty())
			System.out.println("Empty");
		else
			list.printList();

		System.out.println("The list's size is: " + list.getSize());

		System.out.println("*******************");
		System.out.println("The first element is: " + list.getFirst());
		
		System.out.println("*******************");
		System.out.println("The last element is: " + list.getLast());
		
		System.out.println("*******************");
		list.makeEmpty();
		if (list.isEmpty())
			System.out.println("Empty");
		else
			list.printList();

	}
}