Dynamic changes based on arrays and nodes (addition, deletion, modification and query)

First, let's talk about arrays ArrayList

Fixed array format ： int[] arr=new int[10]; // The length is 10 Array of

Generally, when building an array, you need to construct a constant length size , If the array length is not enough in the later stage , You need to create an array to copy .

Array needs to be initialized .

Dynamic expansion array specific code ：

  // You need to define an array 
    public Object[] arr=new Object[8];
    private int size;// The length of the array 

    // add to 
    public  void add(E e){
       // First, create an array 
       Object[] newarr=new Object[arr.length+1];
       // Traversal 
        for (int i=0;i<arr.length;i++){
            newarr[i]=arr[i];
        }
        newarr[arr.length]=e;
        // Update the original array address 
        arr=newarr;
        size++;
    }
    // Add to specific location 

For arrays , The functions of adding, deleting, changing and checking all need to traverse the data in the array before they can be replaced .

Linked list LinkList

• List Attributes of a class ：

  • Storage container ： Array
  • length  
  • Subscript  

• List Class method ：

  • Additive elements ：
    • Add to the end
    • Add to the last Find out When it is full, it needs to be expanded
  • Remove elements ：
    • Delete the last one , The subscript needs to be modified
    • Delete the element with the specified subscript , The following elements need to be moved forward
  • Look for the element ：
    • Find by subscript
    • Find by element

Specific implementation code ：

Write a simple method

 public void add(E e) {
        Node newNode = new Node(e);// Newly established node 
        Node head = root.next;
        if (head == null) {
            head = newNode;
            last = newNode;
        } else {
            last.next = newNode;
            last = newNode;

        }
        size++;
    }