卡码java基础课 | 15.链表的基础操作III

学习内容：
面向对象的方法重载；Java自带的双向链表LinkedList。

重点归纳：
方法的重载：方法名称相同，但参数不同，比如参数个数、参数类型或参数顺序不同，返回类型可以相同也可以不相同。
LinkedList：本质是双向链表结构，定义和声明举例LinkedList list = new LinkedList<>();方法如list.add("aaa")，表示末尾添加。

例题：



解：

点击查看代码

import java.util.Scanner;

//定义链表
class LinkedList{
    
    //定义链表中的链表节点
    public static class Node{
        int data; //数据
        Node next; //指针
        public Node(int data){ //构造函数
            this.data = data;
            this.next = null;
        }
    }
    
    private Node headNode; //头节点
    private int length; //链表长度
    
    public LinkedList(){ //链表的构造函数
        this.length = 0;
        this.headNode = null;
    }
    
    //插入数据函数
    public Node Insert(int location, int data){
        Node newNode = new Node(data);
        if(location > (this.length + 1) || location <= 0){
            System.out.println("Insertion position is invalid.");
            return null;
        }
        else{
            this.length++;
            if(this.headNode == null){
                this.headNode = newNode;
            }
            else{
                if(location == 1){
                    newNode.next = this.headNode;
                    this.headNode = newNode;
                }
                else{
                    Node currentNode = this.headNode;
                    for(int i = 0; i < (location - 2); i++){
                        currentNode = currentNode.next;
                    }
                    newNode.next = currentNode.next;
                    currentNode.next = newNode;
                }
            }
            return newNode;
        }
    }
    
    //删除数据
    public Node Delete(int location){
        if(location <= 0 || location > this.length){
            System.out.println("Deletion position is invalid.");
            return null;
        }
        else{
            this.length--;
            if(location == 1){
                if(this.length == 0){
                    this.headNode = null;
                    return null;
                }
                else{
                    this.headNode = this.headNode.next;
                    return this.headNode;
                }
            }
            else{
                Node currentNode = this.headNode;
                for(int i = 0; i < location - 2; i++){
                    currentNode = currentNode.next;
                }
                currentNode.next = currentNode.next.next;
                return currentNode;
            }
                
        }
    }
    
    public int getLength(){
        return this.length;
    }
    
    //打印数据
    public void printLinkedList(){
        if(this.length != 0){
            Node currentNode = this.headNode;
            while(currentNode != null){
                System.out.print(currentNode.data + " ");
                currentNode = currentNode.next;
            }
            System.out.println();
        }
    }
    
}

public class Main{
    
    public static void main (String[] args) {
        Scanner sc = new Scanner(System.in);
        

        int k = sc.nextInt();
        LinkedList newLinkList = new LinkedList();
        for(int i = 0; i < k; i++){
            int len = newLinkList.getLength();
            int num = sc.nextInt();
            newLinkList.Insert(len + 1, num);
        }
        
        int S = sc.nextInt();
        for(int i = 0; i < S; i++){
            int n = sc.nextInt();
            int x = sc.nextInt();
            if(newLinkList.Insert(n, x) != null){
                newLinkList.printLinkedList();
            }
        }
        
        int L = sc.nextInt();
        for(int i = 0; i < L; i++){
            int loc = sc.nextInt();
            if(newLinkList.Delete(loc) != null){
                newLinkList.printLinkedList();
            }
            
        }
        

        
        sc.close();
    }
    
}