[НП] - Именик

import java.util.*;
import java.util.stream.Collectors;

class DuplicateNumberException extends Exception{
    public DuplicateNumberException(String message) {
        super(message);
    }
}

class Contact{
    private String name;
    private String number;

    public Contact(String name, String number) {
        this.name = name;
        this.number = number;
    }

    public String getName() {
        return name;
    }

    public String getNumber() {
        return number;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Contact contact = (Contact) o;
        return number.equals(contact.number);
    }

    @Override
    public int hashCode() {
        return Objects.hash(number);
    }

    @Override
    public String toString() {
        return name+" "+number;
    }
}

class PhoneBook{
    Set<Contact> contacts;
    Map<String, Set<Contact>> nameMap;

    public PhoneBook() {
        this.contacts = new TreeSet<>(Comparator.comparing(Contact::getName).thenComparing(Contact::getNumber));
        this.nameMap = new HashMap<>();
    }

    public void addContact(String name, String number) throws DuplicateNumberException {
        Contact c = new Contact(name,number);
        if (contacts.contains(c))
            throw new DuplicateNumberException("Duplicate number: "+number);
        contacts.add(c);
        nameMap.computeIfAbsent(name, (k) -> nameMap.put(name, new TreeSet<>(Comparator.comparing(Contact::getName).thenComparing(Contact::getNumber))));
        nameMap.get(name).add(c);
    }

    public void contactsByNumber(String number){
        List<Contact> tmp = contacts.stream().filter(contact -> contact.getNumber().contains(number)).collect(Collectors.toList());
        if (tmp.size()==0)
            System.out.println("NOT FOUND");
        else
            tmp.forEach(System.out::println);
    }

    public void contactsByName(String name){
        if (!nameMap.containsKey(name))
            System.out.println("NOT FOUND");
        else
            nameMap.get(name).forEach(System.out::println);
    }
}

public class PhoneBookTest {

    public static void main(String[] args) {
        PhoneBook phoneBook = new PhoneBook();
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        scanner.nextLine();
        for (int i = 0; i < n; ++i) {
            String line = scanner.nextLine();
            String[] parts = line.split(":");
            try {
                phoneBook.addContact(parts[0], parts[1]);
            } catch (DuplicateNumberException e) {
                System.out.println(e.getMessage());
            }
        }
        while (scanner.hasNextLine()) {
            String line = scanner.nextLine();
            System.out.println(line);
            String[] parts = line.split(":");
            if (parts[0].equals("NUM")) {
                phoneBook.contactsByNumber(parts[1]);
            } else {
                phoneBook.contactsByName(parts[1]);
            }
        }
    }

}