SoftUni Student Academy

package com.company;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.nextLine());
        Map<String, List<Double>> grades = new HashMap<>();

        while (n != 0) {
            String name = sc.nextLine();
            double grade = Double.parseDouble(sc.nextLine());

            if (grades.containsKey(name)) {
                grades.get(name).add(grade);
            } else {
                grades.put(name, new ArrayList<>(Arrays.asList(grade)));
            }
            n--;
        }

        grades.entrySet().stream().sorted(Entry.<String, List<Double>>comparingByValue((v1, v2) ->
            Double.compare(v2.stream().mapToDouble(Double::doubleValue).summaryStatistics().getAverage(),
                v1.stream().mapToDouble(Double::doubleValue).summaryStatistics().getAverage()))
        ).filter((k) -> k.getValue().stream().mapToDouble(Double::doubleValue).summaryStatistics().getAverage() >= 4.5)
        .forEachOrdered(p -> {
            System.out.printf("%s -> %.2f%n", p.getKey(), p.getValue().stream().mapToDouble(Double::doubleValue)
            .summaryStatistics().getAverage());
        });
    }
}