06. Student Academy

package Uprajneniq;

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

public class StudentAcademy {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);


        Map<String, Double> students = new LinkedHashMap<>();
        Map<String, Integer> studentsCount = 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 (!students.containsKey(name)) {
                students.put(name, grade);
                studentsCount.put(name, 1);
            } else {
                double currentGrade = students.get(name);
                int currentCount = studentsCount.get(name);
                double newGrade = (currentGrade * currentCount + grade) / (currentCount + 1);
                students.put(name, newGrade);
                studentsCount.put(name, currentCount + 1);
            }
        }

        students.entrySet().removeIf(entry -> entry.getValue() < 4.5);

        for (Map.Entry<String, Double> entry : students.entrySet()) {
            String name = entry.getKey();
            double averageGrade = entry.getValue();
            System.out.printf("%s -> %.2f%n", name, averageGrade);
        }
    }
}