PriorityQueue Students O(n)

class Student {
    protected
    int id;
    String name;
    double cgpa;

    public Student(int id, String name, double cgpa) {
        this.id = id;
        this.name = name;
        this.cgpa = cgpa;
    }

    public int getID() {
        return id;
    }

    public String getName() {
        return name;
    }

    public double getCgpa() {
        return cgpa;
    }
}

class Priorities {
    public List < Student > getStudents(List < String > events) {

    PriorityQueue < Student > student_queue = new PriorityQueue(Comparator.comparing(Student::getCgpa).reversed().thenComparing(Student::getName).thenComparing(Student::getID));
        List < Student > students = new ArrayList < Student > ();
        for (String e: events) {
            Scanner in =new Scanner(e);
            String event = in.next();
            if (event.equals("ENTER")) {
                String name = in.next();
                double cgpa = in.nextDouble();
                int id = in.nextInt();

                Student student = new Student(id, name, cgpa);
                student_queue.add(student);
            } else if (event.equals("SERVED")) {
                Student first = student_queue.poll();
            } in .close();
        }
        Student first = student_queue.poll();
        if (first == null) {
            return students;
        } else {
            while (first != null) {
                students.add(first);
                first = student_queue.poll();
            }
            return students;
        }

    }
}