Maps, Lambda and Stream API - Exercise - Student Academy

package com.company;

import java.util.*;


public class Main {

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        int n = Integer.parseInt(scanner.nextLine());
        Map<String, List<Double>> students = new LinkedHashMap<>();
        Map<String, Double> finalList = new LinkedHashMap<>();

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

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

        }









        students.entrySet()
                .forEach(e -> {
                            Double average = e.getValue()
                                    .stream()
                                    .mapToDouble(x -> x)
                                    .average()
                                    .getAsDouble();
                            if (average >= 4.50) {
                                finalList.put(e.getKey(), average);
                            }
                        });
        finalList.entrySet()
                .stream()
                .sorted((a,b) -> Double.compare(b.getValue(),
                                    a.getValue()))
                .forEach(c -> {
                                System.out.println(String.format("%s -> %.2f", c.getKey(), c.getValue()));
                            });

    }
}