Student Academy

package com.company;


import java.util.*;
import java.util.stream.Collectors;

public class Main {

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);
        LinkedHashMap<String, ArrayList<Double>> studentsGrades = new LinkedHashMap<>();

        int n = Integer.parseInt(scanner.nextLine());
        for (int i = 0; i < n; i++) {
            String name = scanner.nextLine();
            double grade = Double.parseDouble(scanner.nextLine());

            if (!studentsGrades.containsKey(name)) {
                studentsGrades.put(name, new ArrayList<>());
                studentsGrades.get(name).add(grade);
            } else {
                studentsGrades.get(name).add(grade);
            }

        }
        Map<String, Double> averageStudets = new LinkedHashMap<>();
        for (String name : studentsGrades.keySet()) {
            double sum = 0;
            for (int i = 0; i < studentsGrades.get(name).size(); i++) {
                sum += studentsGrades.get(name).get(i);

            }
            double average = sum / studentsGrades.get(name).size();
            if (average >= 4.50) {
                averageStudets.put(name, average);
            }

        }
        averageStudets.entrySet().stream().sorted(Map.Entry.<String, Double>comparingByValue().reversed())
                .forEach(entry ->
                        System.out.println(String.format("%s -> %.2f", entry.getKey(), entry.getValue())));

    }

}