Thread: LinkedList insert, remove and change

Dear Experts,

I am new to the LinkedList concept and trying out coding a LinkedList problem which require me to do Insert newInteger based on the Index, Remove Index and Change oldInteger to newInteger based on Index.
Please kindly advice what i should code in my

    public void insert(int index, int newInteger) {
        // implementation
    }
 
    public void remove(int index) {
        // implementation
    }
    public void change(int index, int newInteger) {
        // implementation
    }

------------------------------------------------------------------------------------
Sample input

4 8
1 5 2 3
4
I 1 2
R 2
C 1 10
I 4 2

Sample output

YES
NO
NO
NO
------------------------------------------------------------------------------------

Here is my full code:

import java.util.*;
 
//use ListNode to represent the integers.
class ListNode {
    protected Object element;
    protected ListNode next;
 
    public ListNode(Object item){
        element = item;
        next = null;
    }
    //declare constructors
    public ListNode(Object item, ListNode n){
        element = item;
        next = n;
    }
    //get the next list node
    public ListNode getNext(){
        return this.next;
    }
    public Object getElement(){
        return this.element();
    }
}
 
class LinkedList {
    // declare the member field
    protected ListNode head = null;
    protected int num_nodes = 0;
 
    public boolean isEmpty(){
        return (num_nodes == 0);
    }
 
    /* add: add a listNode to the linklist
     * 		PRE-Condition  :
     * 		POST-Condition :
     */
    public void add(ListNode listNode) {
        // implementation
        head = new ListNode (item, head);
        num_nodes ++;
    }
 
    /* insert: insert a newInteger at index
     * 		PRE-Condition  :
     * 		POST-Condition :
     */
    public void insert(int index, int newInteger) {
        // implementation
    }
 
    /* remove: remove the element at index
     * 		PRE-Condition  :
     * 		POST-Condition :
     */
    public void remove(int index) {
        // implementation
    }
 
    /* change: change the integer at index with newInteger
     * 		PRE-Condition  :
     * 		POST-Condition :
     */
    public void change(int index, int newInteger) {
        // implementation
    }
 
    /* isBetter: to compare between this linkedList with prevLinkedList
     * 		PRE-Condition  :
     * 		POST-Condition :
     */
    public String isBetter(LinkedList prevLinkedList) {
		// picking the integers in the newLinkedList and find out the difference between integers in the prevLinkedList
		// and sum the difference up.
		// if the sum of difference is more than K, return "YES"
		// else return "NO"
        int ans = 0;
        for (int i=0; i<prevLinkedList.size(); i ++){
            prevLinkedList.element - element = ans;
        }
        return "YES";
    }
}
 
public class Main {
 
    public static void main(String[] args) {
        // declare the necessary variables
        //int [] array;
        LinkedList <Integer>list = new LinkedList<Integer>();
        int N; //indicate the size of array
        int K; //indicate the citeria
        int Q; //indicate the no.of entry
        String operator; //indicate if it is for insert, remove or change
        int index; //indicate the first input of operator
        int newInteger; //indicate the second input of operator
        int sum;
 
        //declare a Scanner object to read input
        Scanner sc = new Scanner(System.in);
 
        N = sc.nextInt();
        K = sc.nextInt();
 
        list = new int [N];
 
        for (int i=0; i<list.size(); i++){
            list.add(sc.nextInt());
        }
 
        Q = sc.nextInt();
 
        for (int i=0; i<Q; i++){
            operator = sc.next();
 
            if(operator = "I"){
                index = sc.nexInt();
                newInteger = sc.nextInt();
                //int post = index -1;
            }
            else if (operator = "R"){
                index = sc.nextInt();
            }
            else if (operator = "C"){
                index = sc.nextInt();
                newIntegter = sc.nexInt();
                //int post = index -1;
            }
        }
        System.out.println(list.isBetter);
    }
}