5.Average Students Grades

import java.util.*;

public class map1_Lab_5Average_Students_Grades {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = Integer.parseInt(scanner.nextLine());
        Map<String, List<Double>> students = new TreeMap<>();

        for (int i = 0; i < n; i++) {
            String[] input = scanner.nextLine().split("\\s+");
            double grade = Double.parseDouble(input[1]);
            students.putIfAbsent(input[0], new ArrayList<>());
            students.get(input[0]).add(grade);
        }

        for (Map.Entry<String, List<Double>> entry : students.entrySet()) {
            System.out.print(entry.getKey() + " -> ");
            double avg = 0;
            for (Double s : entry.getValue()) {
                System.out.printf("%.2f ", s);
                avg += s;
            }
//            double avg = entry.getValue().stream()
//                    .mapToDouble(Double::doubleValue)
//                    .average()
//                    .getAsDouble();
            System.out.printf("(avg: %.2f)%n", avg / entry.getValue().size());
        }
 }

}