Doubly LinkedList

import java.util.LinkedList;
import java.util.List;

class Node {
    int data;
    Node next;
    Node prev;
}

class MyDoubleLinkedList {
    Node head;
    public void moveMiddleToTop() {
        Node slowPointer = head;
        Node fastPointer = slowPointer;


        while(fastPointer.next != null || fastPointer.next.next != null) {
            slowPointer = slowPointer.next;
            fastPointer = fastPointer.next.next;
        }
        Node temp = head;
        Node beforeSlowPointer = slowPointer.prev;
        beforeSlowPointer.next = slowPointer.next;
        slowPointer.next = head.next;
        head = slowPointer;
    }
}

LinkedList

import java.util.LinkedList;
import java.util.List;

class Main {
    public static void main(String[] args) {
        LinkedList<Integer> linkedList = new LinkedList<>(List.of(1,5,2,3,7,87,345,23,342,5,3,34,5,9));
        System.out.println(occuranceCount(linkedList, 3));
    }

    public static int occuranceCount(LinkedList<Integer> linkedList ,int data) {
        int count = 0;
        for (int i = 0; i < linkedList.size(); i++) {
            if(linkedList.get(i) == data) count++;
        }
        return count;
    }
}