Linked list: A non-contiguous, non-sequential storage structure on the physical storage structure. The logical order of data elements is achieved through the link order of pointers in the linked list.
package algorithm.datastructure.linklist;
import java.util.NoSuchElementException;
/*
* 链表
* 物理存储上非连续的存储结构，数据元素的逻辑顺序是通过链表中的指针链接次序实现
*
* */
public class LinkedList {
private Node head;//头节点
private int size;//链表长度
static private class Node{
private int data;
private Node next;
public Node(){
}
private Node(int data,Node next){
this.data=data;
this.next=next;
}
}
//初始化空链表
public LinkedList(){
//head=null;
}
//添加元素
public Boolean add(int element){
linkLast(element);
return true;
}
//在某个位置之前添加元素
public Boolean add(int index,Integer element){
checkPositionIndex(index);
if (index==size){
linkLast(element);
} else {
linkBefore(element,node(index));
}
return true;
}
//根据下标获取元素
public int get(int index){
checkElementIndex(index);
return node(index).data;
}
//获取第一个元素
public Integer getFirst(){
Node f=head;
if (f==null){
throw new NoSuchElementException();
} else {
return f.data;
}
}
//获取最后一个元素
public Integer getLast(){
if (size==0){
throw new NoSuchElementException();
}
int index=size-1;
return node(index).data;
}
//删除第一个元素
public Integer removeFirst(){
Node f=head;
if (f==null){
throw new NoSuchElementException();
} else {
return unlink(head);
}
}
//删除最后一个元素
public Integer removeLast(){
if (size==0){
throw new NoSuchElementException();
}
int index=size-1;
return unlink(node(index));
}
//根据索引删除元素
public Integer remove(int index){
checkElementIndex(index);
return unlink(node(index));
}
//销毁链表
public void destroyList(){
clearList();
}
//将链表置为空表
public void clearList() {
for (Node p=head;p!=null;){
Node next=p.next;//记录下一个结点
p=null;//删除当前结点
p=next;//指向下一个结点
}
size=0;
head=null;
}
//遍历链表
public void traverseList(){
for (Node p=head;p!=null;){
System.out.println(p.data);
p=p.next;
}
}
//返回链表元素个数
public int size(){
return size;
}
//尾部添加结点
private void linkLast(int element){
Node cur =null,p;
if (size==0){
//没有结点时
head=new Node(element,null);
size++;
return;
}
for (p=head;p!=null;){
//有结点时候
cur=p;
p=cur.next;
}
cur.next= new Node(element,null);//尾部添加元素
size++;
}
//在某结点之前插入结点
private void linkBefore(int element,Node node){
if (node==null){
linkLast(element);
} else {
Node p=head,q=p.next;
if (node.data==p.data){
//node为结点时候
head= new Node(element, p);//在头部插入元素
size++;
} else {
while (p!=null){
if (q.data==node.data) {
p.next= new Node(element,q);//在q之前(p之后)插入一个元素
size++;
break;
}
p=p.next;
q=p.next;
}
}
}
}
//删除结点
private Integer unlink(Node node){
Integer deleteNodeData=null;
Node p=null;
deleteNodeData=node.data;
if (node.data==head.data){
//该节点为头结点
p=head;
head=p.next;
p=null;
size--;
} else {
Node q=head;
for (p=q.next;p!=null;){
//使用两个指针,p,q
if (p.data==node.data){
break;
}
q=q.next;//p始终为q的next结点
p=q.next;
}
q.next=p.next;
p=null;//删除p
size--;
}
return deleteNodeData;
}
//数组下标是否越界
private Boolean isElementIndex(int index){
return index>=0&&index<size;
}
//插入位置是否越界
public Boolean isPositionIndex(int index){
return index>=0&&index<=size;
}
//检验下标是否越界，抛出异常
private void checkElementIndex(int index){
if(!isElementIndex(index)){
try {
throw new IndexOutOfBoundsException("下标越界");
} catch (Exception e) {
e.printStackTrace();
}
}
}
//检验插入下标是否越界，抛出异常
private void checkPositionIndex(int index){
if(!isPositionIndex(index)){
try {
throw new IndexOutOfBoundsException("下标越界");
} catch (Exception e) {
e.printStackTrace();
}
}
}
//返回指定位置的元素
private Node node(int index){
int nowIndex = 0;
if(size>0){
for (Node p=head;p!=null;){
if (nowIndex==index){
return p;
}
p=p.next;
nowIndex++;
}
}
return null;
}
public static void main(String[] args) {
java.util.LinkedList linkedList0=new java.util.LinkedList();
linkedList0.add(6);
linkedList0.remove(0);
linkedList0.size();
linkedList0.peek();
//linkedList0.getFirst();
linkedList0.clear();
//测试
LinkedList linkedList=new LinkedList();
linkedList.add(2);
linkedList.add(6);
linkedList.add(0);
linkedList.add(3);
linkedList.add(8);
linkedList.add(10);
System.out.println(linkedList.get(0));
System.out.println(linkedList.getFirst());
System.out.println(linkedList.getLast());
System.out.println(linkedList.get(5));
System.out.println(linkedList.remove(5));
System.out.println(linkedList.remove(4));
linkedList.remove(2);
linkedList.remove(0);
linkedList.remove(0);
linkedList.remove(0);
linkedList.add(2);
linkedList.add(6);
linkedList.add(0);
linkedList.add(3);
linkedList.add(8);
linkedList.add(10);
linkedList.removeFirst();
linkedList.removeFirst();
linkedList.removeLast();
System.out.println(linkedList.size());
System.out.println("遍历链表");
linkedList.traverseList();
linkedList.add(0,4);
linkedList.add(0,5);
linkedList.add(2,5);
linkedList.add(4,5);
linkedList.add(6,9);
linkedList.add(8,11);
linkedList.add(9,222);
// linkedList.linkBefore(3,new Node(3,null));
// linkedList.linkBefore(3,new Node(2,null));
// linkedList.linkBefore(3,new Node(2,null));
// linkedList.linkBefore(7,new Node(2,null));
// linkedList.linkBefore(9,new Node(7,null));
// linkedList.linkBefore(9,new Node(8,null));
System.out.println("遍历链表");
linkedList.traverseList();
linkedList.clearList();
}
}
The above is the simple implementation of chained storage of linear tables in Java. For more functions, please refer to the LinkedList implementation in Java collections.