Student.java

public class Student implements Comparable<Student>{

    private String name;
    private int score;

    public Student(String name, int score){
        this.name = name;
        this.score = score;
    }

    @Override
    public int compareTo(Student another){

//        if(this.score < another.score)
//            return -1;
//        else if(this.score == another.score)
//            return 0;
//        return 1;

//        return this.score - another.score;
        return another.score - this.score;
    }

    @Override
    public boolean equals(Object student){

        if(this == student)
            return true;

        if(student == null)
            return false;

        if(this.getClass() != student.getClass())
            return false;

        Student another = (Student)student;
        return this.score == another.score;
    }

    @Override
    public String toString(){
        return String.format("Student(name: %s, score: %d)", name, score);
    }
}