diff --git a/CarQueue.java b/CarQueue.java
new file mode 100644
index 0000000..b47483f
--- /dev/null
+++ b/CarQueue.java
@@ -0,0 +1,36 @@
+import java.util.LinkedList;
+import java.util.Queue;
+
+public class CarQueue {
+
+    public static void main(String[] args) {
+        Queue<String> carQueue = new LinkedList<>();
+
+        enqueue(carQueue, "Audi");
+        enqueue(carQueue, "Honda");
+        enqueue(carQueue, "Ford");
+        enqueue(carQueue, "Rolls-Royce");
+
+        printQueueContents(carQueue);
+
+        while (!carQueue.isEmpty()) {
+            String removedCar = dequeue(carQueue);
+            System.out.println(removedCar+" Removed ");
+        }
+
+        if (carQueue.isEmpty()) {
+            System.out.println("The queue is empty.");
+        } else {
+            System.out.println("The queue is not empty.");
+        }
+    }
+    public static void enqueue(Queue<String> queue, String car) {
+        queue.add(car);
+    }
+    public static String dequeue(Queue<String> queue) {
+        return queue.poll();
+    }
+    public static void printQueueContents(Queue<String> queue) {
+        System.out.println("The queue: " + queue);
+    }
+}
\ No newline at end of file
diff --git a/Detective.java b/Detective.java
index 5707416..018f3be 100644
--- a/Detective.java
+++ b/Detective.java
@@ -25,11 +25,18 @@ public static void main(String[] args) {
     poirotsToDos.add("reveal the truth of the crime");
     
     // Print the size of each ArrayList below:
-
+    System.out.println("Sherlock's to-do list size: " + sherlocksToDos.size());
+    System.out.println("Poirot's to-do list size: " + poirotsToDos.size());
     
       
     // Print the name of the detective with the larger to-do list:
-    
+    if (sherlocksToDos.size() > poirotsToDos.size()) {
+      System.out.println("Sherlock Holmes has more tasks.");
+  } else if (sherlocksToDos.size() < poirotsToDos.size()) {
+      System.out.println("Hercules Poirot has more tasks.");
+  } else {
+      System.out.println("Both detectives have the same number of tasks.");
+  }
   }
-  
+  // Poirot kar bishtari darad.
 }
diff --git a/HashCollisionChecker.java b/HashCollisionChecker.java
index 80631a7..5214dbf 100644
--- a/HashCollisionChecker.java
+++ b/HashCollisionChecker.java
@@ -1,14 +1,22 @@
-import java.util.*;
+import java.util.HashMap;
+import java.util.HashSet;
 
 public class HashCollisionChecker {
+
     public static <T> int countOfUniqueHashCodes(HashSet<T> set) {
-        // TODO: Implement
-        return 0;
+        HashSet<Integer> uniqueHashCodes = new HashSet<>();
+        for (T item : set) {
+            uniqueHashCodes.add(item.hashCode());
+        }
+        return uniqueHashCodes.size();
     }
 
     public static <K, V> int countOfUniqueHashCodes(HashMap<K, V> map) {
-        // TODO: Implement
-        return 0;
+        HashSet<Integer> uniqueHashCodes = new HashSet<>();
+        for (K key : map.keySet()) {
+            uniqueHashCodes.add(key.hashCode());
+        }
+        return uniqueHashCodes.size();
     }
 
     public static void main(String[] args) {
diff --git a/Shuffle.java b/Shuffle.java
new file mode 100644
index 0000000..94a4654
--- /dev/null
+++ b/Shuffle.java
@@ -0,0 +1,25 @@
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.Scanner;
+
+public class Shuffle {
+
+    public static void main(String[] args) {
+        LinkedList<String> list = new LinkedList<>();
+        Scanner scanner = new Scanner(System.in);
+
+        System.out.println("Enter the number of elements in the list:");
+        int numberOfElements = scanner.nextInt();
+        scanner.nextLine();
+
+        System.out.println("Enter the elements :");
+        for (int i = 0; i < numberOfElements; i++) {
+            String element = scanner.nextLine();
+            list.add(element);
+        }
+
+        System.out.println("Original list: " + list);
+        Collections.shuffle(list);
+        System.out.println("Shuffled list: " + list);
+    }
+}
\ No newline at end of file
diff --git a/StudentManager.java b/StudentManager.java
new file mode 100644
index 0000000..a7a149e
--- /dev/null
+++ b/StudentManager.java
@@ -0,0 +1,82 @@
+import java.util.Comparator;
+import java.util.Scanner;
+import java.util.TreeSet;
+
+class Student {
+    private final String name;
+    private final int studentNumber;
+    private final double gpa;
+
+    public Student(String name, int studentNumber, double gpa) {
+        this.name = name;
+        this.studentNumber = studentNumber;
+        this.gpa = gpa;
+    }
+
+    public int getStudentNumber() {
+        return studentNumber;
+    }
+
+    @Override
+    public String toString() {
+        return "Name: " + name + ", Student Number: " + studentNumber + ", GPA: " + gpa;
+    }
+}
+
+class StudentComparator implements Comparator<Student> {
+    @Override
+    public int compare(Student s1, Student s2) {
+        return Integer.compare(s1.getStudentNumber(), s2.getStudentNumber());
+    }
+}
+
+public class StudentManager {
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+        TreeSet<Student> students = new TreeSet<>(new StudentComparator());
+
+        // Receiving student details from user
+        System.out.print("Enter the number of students: ");
+        int numberOfStudents = scanner.nextInt();
+        scanner.nextLine(); // Consume newline
+
+        for (int i = 0; i < numberOfStudents; i++) {
+            System.out.println("Enter details for student " + (i + 1) + ":");
+
+            System.out.print("Name: ");
+            String name = scanner.nextLine();
+
+            System.out.print("Student Number: ");
+            int studentNumber = scanner.nextInt();
+
+            System.out.print("GPA: ");
+            double gpa = scanner.nextDouble();
+            scanner.nextLine(); // Consume newline
+
+            students.add(new Student(name, studentNumber, gpa));
+        }
+
+        // Searching for a student by student number
+        System.out.print("Enter student number to search: ");
+        int searchStudentNumber = scanner.nextInt();
+
+        Student searchStudent = null;
+        for (Student student : students) {
+            if (student.getStudentNumber() == searchStudentNumber) {
+                searchStudent = student;
+                break;
+            }
+        }
+
+        if (searchStudent != null) {
+            System.out.println("Student found: " + searchStudent);
+        } else {
+            System.out.println("Student with student number " + searchStudentNumber + " not found.");
+        }
+
+        scanner.close();
+    }
+}
+
+
+