import java.util.*;

public class MapsPractice {

public static void main(String[] args) {

HashMap<String, List<String>> h1 = new LinkedHashMap<>();

HashMap<String, String> h2 = new LinkedHashMap<>();

// Check if HashMap is empty

System.out.println("is studentsMapping empty?: " + h1.isEmpty());

System.out.println("is studentsMapping empty?: " + h2.isEmpty());

// creating list of subjects and adding to hash map

List<String> subjects = Arrays.asList("Python", "Math", "C");

h1.put("A", subjects);

subjects = Arrays.asList("C", "C++");

h1.put("B", subjects);

subjects = Arrays.asList("C++", "Physics", "Chemistry");

h1.put("C", subjects);

// creating hashmap of faculty

h2.put("Python", "111");

h2.put("Math", "222");

h2.put("C", "333");

h2.put("C++", "444");

// displaying all students and subjects

for (Map.Entry m : h1.entrySet()) {

System.out.println(m.getKey());

subjects = (List<String>) m.getValue();

for (String s : subjects)

System.out.print(s + " ");

System.out.println();

}

// displaying all subjects and faculty

for (Map.Entry m : h2.entrySet()) {

System.out.println(m.getKey() + " " + m.getValue());

}

// Scanner sc = new Scanner(System.in);

// System.out.print("Enter a student: ");

String s = "B";

System.out.println("Faculties are: ");

for (Map.Entry m : h1.entrySet()) {

if (m.getKey().equals(s)) {

for (Map.Entry m2 : h2.entrySet()) {

subjects = (List<String>) m.getValue();

if (subjects.contains(m2.getKey()))

System.out.println(m2.getValue());

}

}

}

}

}