数据结构(更新至链表)

发布时间:2024年01月22日

数组

数组的代码

public class Myarr<T> {

    private int capacity=0;
    private int size=0;
    private T[]arr;

    //如果是空的则强制将容量扩充为10
    public Myarr(int capacity) {
        if (this.size == 0) {
            this.capacity = 10;
            this.arr=(T[]) new Object[this.capacity];
        }
    }

    //按顺序添加数据
    public void add(T value){
        if(this.size>=capacity){
            T[]arr1=Arrays.copyOf(arr,2*this.capacity);
            this.arr=arr1;
            this.capacity=this.capacity*2;
        }
        arr[this.size++]=value;

    }

    //按下标删除数据
    public void delete(int index){
        if(index>=this.size||index<0){
            System.out.println("输入有误");
            return;
        }
        if((this.size<=capacity/4)&&(capacity/4>0)){
            T []arr1=Arrays.copyOf(arr,this.capacity/4);
            this.arr=arr1;
            this.capacity=this.capacity/4;
        }
        for(int i=index+1;i<this.size;i++){
            arr[i-1]=arr[i];
        }
        this.size--;
    }

    //查找指定下标的数据
    public void search(int index){
        if(index>=this.size||index<0){
            System.out.println("输入有误");
            return;
        }
        System.out.println(index+"处的值为:"+arr[index]);
    }

    //修改指定下标的值
    public void modify(int index,T value){
        if(index>=this.size||index<0){
            System.out.println("输入有误");
            return;
        }
        arr[index]=value;
    }

    //将数组转为字符串输出
    @Override
    public String toString() {
        StringBuffer stringBuffer=new StringBuffer();
        stringBuffer.append('[');
        for(int i=0;i<this.size;i++){
            stringBuffer.append(arr[i]);
            if(i!=this.size-1){
                stringBuffer.append(",");
            }
        }
        stringBuffer.append("]");
        return stringBuffer.toString();
    }

    //向数组指定位置添加数值
    public void aimedAdd(int index,T value){
        if(index<0||index>this.capacity){
            throw new IllegalArgumentException("索引越界!");
        }
        if(this.size>=capacity){
            T []arr1=Arrays.copyOf(arr,2*this.capacity);
            this.arr=arr1;
            this.capacity=this.capacity*2;
        }//当添加的数值大于数组实际长度时将进行扩容
        this.size++;
        for(int i=this.size;i>index;i--){
            arr[i]=arr[i-1];
        }
        arr[index]=value;
    }

    //获取数组长度
    public int getsize(){
        return this.size;
    }

    //获取数组容积
    public int getCapacity(){
        return this.capacity;
    }

    public T remove(){
        if((this.size<=capacity/4)&&(capacity/4>0)){
            T []arr1=Arrays.copyOf(arr,this.capacity/4);
            this.arr=arr1;
            this.capacity=this.capacity/4;
        }//当数组实际使用长度小于容积的四分之一时将对容积进行缩容
        arr[size]=null;
        this.size--;
        return arr[size];
    }
    public T gethead(){
        return arr[size-1];
    }
}

链表

链表的代码

public class MyLinkList<T> {
    class Node<T>{//使用内部类创建节点
        T data;//节点本身的数据
        Node next;//指向下一个节点

        public Node(T data,Node node){//内部类的构造
        this.data=data;
        this.next=node.next;
        }
        public Node(T data){
            this.data=data;
            this.next=null;
        }
    }


    //链表相关的属性和方法
    private Node head;//链表的头结点
    private int size;

    public MyLinkList(){
        this.head=new Node(null);
        this.size=0;
    }

    //判断链表是否为空
    public boolean isEmpty(){
        return this.size==0;
    }
    //头部插入元素
    public void addHead(T data){
        //1.创建结点
        Node node=new Node(data);
        node.next=node;
        //2.挂接
        node.next=this.head;
        this.head=node;
        //3.更新size
        this.size++;
    }

    public void addTail(T data){
        Node node=new Node(data);
        Node curnode=this.head;
        if(this.head==null){
            this.head=node;
        }else {
            while (curnode.next!=null){
                curnode=curnode.next;
            }
            curnode.next=node;
        }
        this.size++;
    }

    //获取链表大小
    public int getsize(){
        return this.size;
    }

    // 重写toString 打印链表中的数据
    @Override
    public String toString(){
        //从头结点开始向后遍历
        Node curnode=this.head;
        StringBuffer stringBuffer=new StringBuffer();
        while(curnode!=null){
            stringBuffer.append(curnode.data+"--->");
            curnode=curnode.next;

        }
        stringBuffer.append("null");
        return stringBuffer.toString();
    }

    //根据索引获得链表的值
    public T getByIndex(int index){
        //1.判断索引是否有效
        if(index<0||index>this.size){
            throw new IllegalArgumentException("索引无效");
        }
        Node<T> curNode=this.head.next;
        int i=0;
        while(i<index){
            curNode=curNode.next;
            i++;
        }
        return curNode.data;
    }

    //从链表头部删除元素
    public T deleteHead(){
        if(this.isEmpty()){
            return null;
        }
        Node<T> delNode=this.head.next;
        this.head.next=delNode.next;
        delNode.next=null;
        this.size--;
        return delNode.data;
    }

    //从链表尾部删除元素
    public T deletetail(){
        if (this.isEmpty()){
            return null;
        }
        Node<T> pre=this.head;
        while(pre.next.next!=null){
            pre=pre.next;
        }
        this.size--;
        Node<T> delNode=pre.next;
        pre.next=delNode.next;
        delNode.next=null;
        return delNode.data;
    }

    //在链表任意位置删除
    public T deleteByIndex(int index){
        int count=1;
        if(index<0||index>this.size){
            return null;
        }
        Node<T> pre=this.head;
        while(pre.next!=null) {
            pre = pre.next;
            count++;
            if (count == index) {
                break;
            }
        }
            Node<T> delNode=pre.next;
            pre.next=delNode.next;
            delNode.next=null;
            return delNode.data;

    }

    //根据值在链表中删除元素
    public int removeByValue(T value){
        int count=0;
        //定义前驱结点
        Node<T> pre=this.head;
        while(pre.next!=null){
            Node<T> curNode=pre.next;
            if(curNode.data.equals(value)){
                pre.next=pre.next.next;
                curNode.data=null;
                this.size--;
                count++;
            }else{
                pre=pre.next;
            }
        }
        return count;
    }
}

  • 线性结构

  • 数据只能从栈顶进,栈顶出

    图示

基于数组实现的栈

数组的代码:

public class Myarr<T> {

    private int capacity=0;
    private int size=0;
    private T[]arr;

    //如果是空的则强制将容量扩充为10
    public Myarr(int capacity) {
        if (this.size == 0) {
            this.capacity = 10;
            this.arr=(T[]) new Object[this.capacity];
        }
    }

    //按顺序添加数据
    public void add(T value){
        if(this.size>=capacity){
            T[]arr1=Arrays.copyOf(arr,2*this.capacity);
            this.arr=arr1;
            this.capacity=this.capacity*2;
        }
        arr[this.size++]=value;

    }

    //按下标删除数据
    public void delete(int index){
        if(index>=this.size||index<0){
            System.out.println("输入有误");
            return;
        }
        if((this.size<=capacity/4)&&(capacity/4>0)){
            T []arr1=Arrays.copyOf(arr,this.capacity/4);
            this.arr=arr1;
            this.capacity=this.capacity/4;
        }
        for(int i=index+1;i<this.size;i++){
            arr[i-1]=arr[i];
        }
        this.size--;
    }

    //查找指定下标的数据
    public void search(int index){
        if(index>=this.size||index<0){
            System.out.println("输入有误");
            return;
        }
        System.out.println(index+"处的值为:"+arr[index]);
    }

    //修改指定下标的值
    public void modify(int index,T value){
        if(index>=this.size||index<0){
            System.out.println("输入有误");
            return;
        }
        arr[index]=value;
    }

    //将数组转为字符串输出
    @Override
    public String toString() {
        StringBuffer stringBuffer=new StringBuffer();
        stringBuffer.append('[');
        for(int i=0;i<this.size;i++){
            stringBuffer.append(arr[i]);
            if(i!=this.size-1){
                stringBuffer.append(",");
            }
        }
        stringBuffer.append("]");
        return stringBuffer.toString();
    }

    //向数组指定位置添加数值
    public void aimedAdd(int index,T value){
        if(index<0||index>this.capacity){
            throw new IllegalArgumentException("索引越界!");
        }
        if(this.size>=capacity){
            T []arr1=Arrays.copyOf(arr,2*this.capacity);
            this.arr=arr1;
            this.capacity=this.capacity*2;
        }
        this.size++;
        for(int i=this.size;i>index;i--){
            arr[i]=arr[i-1];
        }
        arr[index]=value;
    }

    //获取数组长度
    public int getsize(){
        return this.size;
    }

    //获取数组容积
    public int getCapacity(){
        return this.capacity;
    }

    public T remove(){
        if((this.size<=capacity/4)&&(capacity/4>0)){
            T []arr1=Arrays.copyOf(arr,this.capacity/4);
            this.arr=arr1;
            this.capacity=this.capacity/4;
        }
        arr[size]=null;
        this.size--;
        return arr[size];
    }
    public T gethead(){
        return arr[size-1];
    }
}

数组实现的栈的代码:

public class ArrStack<T> implements Mystack<T>{

    private Myarr<T> data;

    public ArrStack(Myarr data) {
        this.data = data;
    }

    @Override
    public void push(T value) {
        this.data.add(value);
    }

    @Override
    public T pop() {
        return this.data.remove();
    }

    @Override
    public T peek() {
        return this.data.gethead();
    }

    @Override
    public boolean IsEmpty() {
        if(this.data.getsize()==0){
        return true;
        }else{
            return false;
        }
    }
}

基于链表实现的栈

链表的代码

public class MyLinkList<T> {
    class Node<T>{//使用内部类创建节点
        T data;//节点本身的数据
        Node next;//指向下一个节点

        public Node(T data,Node node){//内部类的构造
        this.data=data;
        this.next=node.next;
        }
        public Node(T data){
            this.data=data;
            this.next=null;
        }
    }


    //链表相关的属性和方法
    private Node head;//链表的头结点
    private int size;

    public MyLinkList(){
        this.head=new Node(null);
        this.size=0;
    }

    //判断链表是否为空
    public boolean isEmpty(){
        return this.size==0;
    }
    //头部插入元素
    public void addHead(T data){
        //1.创建结点
        Node node=new Node(data);
        node.next=node;
        //2.挂接
        node.next=this.head;
        this.head=node;
        //3.更新size
        this.size++;
    }

    public void addTail(T data){
        Node node=new Node(data);
        Node curnode=this.head;
        if(this.head==null){
            this.head=node;
        }else {
            while (curnode.next!=null){
                curnode=curnode.next;
            }
            curnode.next=node;
        }
        this.size++;
    }

    //获取链表大小
    public int getsize(){
        return this.size;
    }

    // 重写toString 打印链表中的数据
    @Override
    public String toString(){
        //从头结点开始向后遍历
        Node curnode=this.head;
        StringBuffer stringBuffer=new StringBuffer();
        while(curnode!=null){
            stringBuffer.append(curnode.data+"--->");
            curnode=curnode.next;

        }
        stringBuffer.append("null");
        return stringBuffer.toString();
    }

    //根据索引获得链表的值
    public T getByIndex(int index){
        //1.判断索引是否有效
        if(index<0||index>this.size){
            throw new IllegalArgumentException("索引无效");
        }
        Node<T> curNode=this.head.next;
        int i=0;
        while(i<index){
            curNode=curNode.next;
            i++;
        }
        return curNode.data;
    }

    //从链表头部删除元素
    public T deleteHead(){
        if(this.isEmpty()){
            return null;
        }
        Node<T> delNode=this.head.next;
        this.head.next=delNode.next;
        delNode.next=null;
        this.size--;
        return delNode.data;
    }

    //从链表尾部删除元素
    public T deletetail(){
        if (this.isEmpty()){
            return null;
        }
        Node<T> pre=this.head;
        while(pre.next.next!=null){
            pre=pre.next;
        }
        this.size--;
        Node<T> delNode=pre.next;
        pre.next=delNode.next;
        delNode.next=null;
        return delNode.data;
    }

    //在链表任意位置删除
    public T deleteByIndex(int index){
        int count=1;
        if(index<0||index>this.size){
            return null;
        }
        Node<T> pre=this.head;
        while(pre.next!=null) {
            pre = pre.next;
            count++;
            if (count == index) {
                break;
            }
        }
            Node<T> delNode=pre.next;
            pre.next=delNode.next;
            delNode.next=null;
            return delNode.data;

    }

    //根据值在链表中删除元素
    public int removeByValue(T value){
        int count=0;
        //定义前驱结点
        Node<T> pre=this.head;
        while(pre.next!=null){
            Node<T> curNode=pre.next;
            if(curNode.data.equals(value)){
                pre.next=pre.next.next;
                curNode.data=null;
                this.size--;
                count++;
            }else{
                pre=pre.next;
            }
        }
        return count;
    }
}

链表实现的栈的代码

public class LinkedStack<T> implements Mystack{
    private MyLinkList<T> data;
    public LinkedStack(){
        this.data=new MyLinkList<>();
    }
    @Override
    public void push(Object value) {
        this.data.addTail((T) value);
    }

    @Override
    public T pop() {
        return this.data.deleteHead();
    }

    @Override
    public Object peek() {
        return this.data.getByIndex(data.getsize());
    }

    @Override
    public boolean IsEmpty() {
        return this.data.isEmpty();
    }
}

栈的接口

public interface Mystack <T>{
    void push(T value);
    T pop();
    T peek();
    boolean IsEmpty();

}
文章来源:https://blog.csdn.net/lalala1213888/article/details/135756579
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