Dev

pom.xml

@@ -21,16 +21,18 @@
     </build>
 
     <dependencies>
-        <dependency>
-            <groupId>junit</groupId>
-            <artifactId>junit</artifactId>
-            <version>LATEST</version>
-        </dependency>
 
         <dependency>
             <groupId>org.projectlombok</groupId>
             <artifactId>lombok</artifactId>
             <version>LATEST</version>
         </dependency>
+
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <version>5.10.2</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 </project>

src/main/java/faangschool/magic/Main.java

@@ -0,0 +1,40 @@
+package faangschool.magic;
+
+import fromsber.Employee;
+
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.List;
+
+public class Main {
+    public static void main(String[] args) {
+        Student student = new Student();
+        Student student2 = new Student();
+        Student student3 = new Student();
+        Student student4 = new Student();
+
+        student2.setAge(15);
+        student2.setName("Alpha");
+        student.setAge(18);
+        student.setName("Mozol");
+        student4.setAge(16);
+        student4.setName("Bruce");
+        student3.setAge(56);
+        student3.setName("Zoo");
+
+        Student[] students = new Student[]{student, student2, student3, student4};
+
+        System.out.println("Unsorted array " + Arrays.toString(students));
+
+        Arrays.sort(students);
+
+        System.out.println("Sorted array " + Arrays.toString(students));
+
+        Arrays.stream(students).sorted(new StudentNameComparatorASC()).forEach(System.out::println);
+        System.out.println();
+
+        Arrays.stream(students).sorted(new StudentNameComparatorDESC()).forEach(System.out::println);
+
+
+    }
+}

src/main/java/faangschool/magic/Student.java

@@ -0,0 +1,60 @@
+package faangschool.magic;
+
+
+import java.util.Arrays;
+import java.util.Comparator;
+
+public class Student
+        implements Comparable<Student> {
+    private String name;
+    private int age;
+    private String faculty;
+    private String[] abilities;
+
+    public String getName() {
+        return name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public String getFaculty() {
+        return faculty;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    @Override
+    public String toString() {
+        return "Student{" +
+                "name='" + name + '\'' +
+                ", age=" + age +
+//                ", faculty='" + faculty + '\'' +
+//                ", abilities=" + Arrays.toString(abilities) +
+                '}';
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    public void setFaculty(String faculty) {
+        this.faculty = faculty;
+    }
+
+    public void setAbilities(String[] abilities) {
+        this.abilities = abilities;
+    }
+
+    public String[] getAbilities() {
+        return abilities;
+    }
+
+    @Override
+    public int compareTo(Student o) {
+        return this.age - o.age;
+    }
+}

src/main/java/faangschool/magic/StudentNameComparatorASC.java

@@ -0,0 +1,11 @@
+package faangschool.magic;
+
+import java.util.Comparator;
+
+public class StudentNameComparatorASC implements Comparator<Student> {
+
+    @Override
+    public int compare(Student o1, Student o2) {
+        return o1.getName().compareTo(o2.getName());
+    }
+}

src/main/java/faangschool/magic/StudentNameComparatorDESC.java

@@ -0,0 +1,10 @@
+package faangschool.magic;
+
+import java.util.Comparator;
+
+public class StudentNameComparatorDESC implements Comparator<Student> {
+    @Override
+    public int compare(Student o1, Student o2) {
+        return o2.getName().compareTo(o1.getName());
+    }
+}

src/main/java/faangschool/magic/collection/CompositeKey.java

@@ -0,0 +1,19 @@
+package faangschool.magic.collection;
+
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Data;
+
+@AllArgsConstructor
+@Data
+@Builder
+public class CompositeKey {
+
+    private final String faculty;
+    private final int year;
+
+
+}
+
+

src/main/java/faangschool/magic/collection/CountOccurrences.java

@@ -0,0 +1,17 @@
+package faangschool.magic.collection;
+
+import java.util.HashMap;
+
+public class CountOccurrences {
+    public static void main(String[] args) {
+        int[] arr = {1, 2, 3, 4, 2, 1, 3, 4, 5, 1};
+
+        HashMap<Integer, Integer> map = new HashMap<>();
+
+        for (int i : arr) {
+            map.put(i, map.getOrDefault(i, 0) + 1);
+        }
+
+        System.out.println(map);
+    }
+}

src/main/java/faangschool/magic/collection/Main.java

@@ -0,0 +1,72 @@
+package faangschool.magic.collection;
+
+import java.util.*;
+import java.util.stream.Collectors;
+
+import static java.util.List.*;
+
+public class Main {
+
+    public static List<Student> initStudents;
+    public static Map<CompositeKey, List<Student>> students;
+
+    static {
+        initStudents = of(
+                Student.builder().name("Boris").faculty("Math").year(2006).build(),
+                Student.builder().name("Vasily").faculty("Physic").year(2011).build(),
+                Student.builder().name("Nick").faculty("Chemistry").year(2015).build(),
+                Student.builder().name("Ahmed").faculty("Math").year(2003).build(),
+                Student.builder().name("Marina").faculty("Economic").year(2013).build(),
+                Student.builder().name("Olga").faculty("Biology").year(2005).build(),
+                Student.builder().name("Maria").faculty("Chemistry").year(2015).build(),
+                Student.builder().name("Georgy").faculty("Physic").year(2004).build(),
+                Student.builder().name("Stepan").faculty("Literature").year(2008).build(),
+                Student.builder().name("Anna").faculty("Literature").year(2004).build(),
+                Student.builder().name("Semen").faculty("Physic").year(2011).build()
+        );
+
+        students = getStudentsGroupingByFacultyAndYear(initStudents);
+    }
+
+
+    public static void main(String[] args) {
+
+        for (Map.Entry<CompositeKey, List<Student>> entry: students.entrySet()) {
+            System.out.println();
+        }
+    }
+
+    public static Map<CompositeKey, List<Student>> getStudentsGroupingByFacultyAndYear(List<Student> students){
+        return students
+                .stream()
+                .collect(Collectors.groupingBy(c-> new CompositeKey(c.getFaculty(), c.getYear())));
+    }
+
+    //TODO 16.08.2024 - 8:29: refactor method
+    public static boolean addStudent(Student student) {
+        ArrayList<Student> emptyStudentsLists = new ArrayList<>();
+
+        if(student != null) {
+            CompositeKey key = new CompositeKey(student.getFaculty(), student.getYear());
+
+            if(!students.containsKey(key)) {
+                students.put(key, students.getOrDefault(key, emptyStudentsLists));
+                return true;
+            }
+        } else{
+            return false;
+        }
+        return false;
+    }
+
+    //TODO 16.08.2024 - 8:29: refactor method
+    public static boolean deleteStudent(Student student) {
+        CompositeKey maybeStudent = new CompositeKey(student.getFaculty(), student.getYear());
+        if(students.containsKey(maybeStudent)) {
+            students.remove(maybeStudent);
+            return true;
+        } else {
+            return false;
+        }
+    }
+}

src/main/java/faangschool/magic/collection/MutableKey.java

@@ -0,0 +1,33 @@
+package faangschool.magic.collection;
+
+import java.util.Objects;
+
+public class MutableKey {
+
+    private String key;
+
+    public MutableKey(String key) {
+        this.key = key;
+    }
+
+    public void setKey(String key) {
+        this.key = key;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if(o == null || getClass() != o.getClass()) {
+            return false;
+        }
+        MutableKey that = (MutableKey) o;
+        return Objects.equals(key, that.key);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(key);
+    }
+}

src/main/java/faangschool/magic/collection/ReverseMapping.java

@@ -0,0 +1,24 @@
+package faangschool.magic.collection;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+public class ReverseMapping {
+    public static void main(String[] args) {
+
+        HashMap<String, String> countryCapital = new HashMap<>();
+        countryCapital.put("France", "Paris");
+        countryCapital.put("England", "London");
+        countryCapital.put("Russia", "Moscow");
+
+        System.out.println(countryCapital);
+
+        Map<String, String> capitalCountry = countryCapital
+                .entrySet()
+                .stream()
+                .collect(Collectors.toMap(Map.Entry::getValue, Map.Entry::getKey));
+
+        System.out.println(capitalCountry);
+    }
+}

src/main/java/faangschool/magic/collection/Student.java

@@ -0,0 +1,16 @@
+package faangschool.magic.collection;
+
+import lombok.Builder;
+import lombok.Data;
+
+@Data
+@Builder
+public class Student {
+
+    private String name;
+    private String faculty;
+    private int year;
+
+
+
+}

src/main/java/fromsber/Employee.java

@@ -0,0 +1,36 @@
+package fromsber;
+
+public class Employee {
+
+    private String name;
+    private Status status;
+
+    public Employee(String name, Status status) {
+        this.name = name;
+        this.status = status;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Status getStatus() {
+        return status;
+    }
+
+    @Override
+    public String toString() {
+        return "Employee{" +
+                "name='" + name + '\'' +
+                ", status=" + status +
+                '}';
+    }
+
+    public void setStatus(Status status) {
+        this.status = status;
+    }
+}