Student Academy

import java.util.*;

public class StudentAcademy {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int countStudents = Integer.parseInt(scanner.nextLine());

        Map<String, List<Double>> studentsGrades = new LinkedHashMap<>();

        for (int i = 0; i < countStudents; i++) {
            String studentName = scanner.nextLine();
            double grade = Double.parseDouble(scanner.nextLine());
            if (!studentsGrades.containsKey(studentName)) {
                studentsGrades.put(studentName, new ArrayList<>());
            }
            studentsGrades.get(studentName).add(grade);
        }
        Map<String, Double> studentAverageGrade = new LinkedHashMap<>();

        for (Map.Entry<String, List<Double>> entry : studentsGrades.entrySet()) {

            String studentName = entry.getKey();
            List<Double> grades = entry.getValue();
            double averageGrade = getAverageGrade(grades);
            if (averageGrade >= 4.50) {
                studentAverageGrade.put(studentName, averageGrade);
            }
        }
        studentAverageGrade
                .entrySet()
                .stream()
                .sorted((entry1, entry2) -> entry2.getValue()
                        .compareTo(entry1.getValue()))
                .forEach(entry -> System.out.printf
                        ("%s -> %.2f%n", entry.getKey(), entry.getValue()));

    }

    private static double getAverageGrade(List<Double> grades) {
        double sumGrades = 0;
        for (double grade : grades) {
            sumGrades += grade;
        }
        return sumGrades / grades.size();
    }
}