5WBx2RL4

1public class Membership {
2
3    static List<User> users =new ArrayList<>();;
4    static Map<String,Integer> userByNumberOfRegistrations= new HashMap<>();
5
6
7    public static void createUser(String username, String password, String email, String country, Integer age) {
8           Membership.users.add(new User(username,password,email,country,age));
9           userByNumberOfRegistrations.putIfAbsent(email,0);
10           userByNumberOfRegistrations.computeIfPresent(email,(k,v)->v=v+1);
11    }
12
13    public static Map<String,Integer> getNDifferentUsersByEmail() {
14        return userByNumberOfRegistrations.entrySet().stream()
15                .sorted(Comparator.comparing((Map.Entry<String,Integer> entry)->entry.getValue(),Comparator.reverseOrder()))
16                .collect(Collectors.toMap(
17                        entry->entry.getKey(),
18                        entry->entry.getValue(),
19                        (e1, e2) -> e1,
20                        LinkedHashMap::new
21                ));
22
23    }
24
25    public static List<User> getUsersOrderedByEmail() {
26        return users.stream().sorted().collect(Collectors.toList());
27    }
28
29    public static boolean deleteUser(int userId) {
30        User u = users.stream().filter(i->i.id == userId).findAny().orElse(null);
31        if(u != null){
32            users.remove(u);
33            userByNumberOfRegistrations.computeIfPresent(u.getEmail(),(k,v)->v=Math.max(0,v-1));
34            if(userByNumberOfRegistrations.get(u.getEmail())==0){
35                userByNumberOfRegistrations.remove(u.getEmail());
36            }
37            return true;
38        }
39        return false;
40    }
41}
42
43public class User implements Comparable<User>{
44    String username;
45    String password;
46    String email;
47    PersonalInformation personalInformation;
48    int id;
49    public static int ID_GENERATOR=0;
50
51    public User(String username, String password, String email, String country, Integer age) {
52        this.username= username;
53        this.password = password;
54        this.email = email;
55        this.personalInformation = new PersonalInformation(country, age);
56        ++ID_GENERATOR;
57        this.id = ID_GENERATOR;
58    }
59
60    public String getUsername() {
61        return username;
62    }
63
64    public String getPassword() {
65        return password;
66    }
67
68    public String getEmail() {
69        return email;
70    }
71
72    public PersonalInformation getPersonalInformation() {
73        return personalInformation;
74    }
75
76    public int getId() {
77        return id;
78    }
79
80    @Override
81    public String toString() {
82        return String.format("%d: %s, %s", id, username, email);
83    }
84
85    @Override
86    public int compareTo(User o) {
87        return Comparator.comparing(User::getEmail).compare(this,o);
88    }
89}
90
91public class PersonalInformation {
92    String country;
93    int age;
94
95    public PersonalInformation(String country, int age) {
96        this.country = country;
97        this.age = age;
98    }
99
100    public String getCountry() {
101        return country;
102    }
103
104    public int getAge() {
105        return age;
106    }
107}
108
109public class MembershipTest {
110    public static void main(String[] args) {
111        Scanner scanner = new Scanner(System.in);
112        int length = scanner.nextInt();
113        scanner.nextLine();
114        for(int i=0;i<length;i++){
115            String username = scanner.nextLine();
116            String password = scanner.nextLine();
117            String email = scanner.nextLine();
118            String country = scanner.nextLine();
119            Integer age = scanner.nextInt();
120            scanner.nextLine();
121            Membership.createUser(username,password,email,country,age);
122        }
123
124        for(int i=0;i<length;i++){
125            System.out.println(Membership.getNDifferentUsersByEmail());
126            System.out.println(Membership.getUsersOrderedByEmail());
127            System.out.println(Membership.deleteUser(i+1));
128        }
129
130        System.out.println(Membership.deleteUser(1));
131    }
132}