P7_Student Academy_Maps_Ex

package ex1_MapsLambdaStreamAPI_13March2019;

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;

public class P7_StudentAcademy {
    public static void main(String[] args) {
        @SuppressWarnings("resource")

        Scanner sc = new Scanner(System.in);

        int n = Integer.parseInt(sc.nextLine());

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

        for (int i = 0; i < n; i++) {
            String name = sc.nextLine();
            Double grade = Double.parseDouble(sc.nextLine());

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

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

        for (String name : academy.keySet()) {
            double sum = 0;

            for (int i = 0; i < academy.get(name).size(); i++) {
                sum += academy.get(name).get(i);
            }

            double average = sum / academy.get(name).size();

            if (average >= 4.50) {
                averageGrades.put(name, average);
            }
        }

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