diff --git a/CarQueue.java b/CarQueue.java
new file mode 100644
index 0000000..ca8ec50
--- /dev/null
+++ b/CarQueue.java
@@ -0,0 +1,26 @@
+import java.util.LinkedList;
+import java.util.Queue;
+
+public class CarQueue {
+    public static void main(String[] args) {
+        Queue<String> queue = new LinkedList<>();
+
+        queue.add("Car 1");
+        queue.add("Car 2");
+        queue.add("Car 3");
+        queue.add("Car 4");
+
+        System.out.println(queue);
+
+        while (!queue.isEmpty()) {
+            String removedCar = queue.poll();
+            System.out.println("delete: " + removedCar);
+        }
+
+        if (queue.isEmpty()) {
+            System.out.println("queue is empty.");
+        } else {
+            System.out.println("queue isn't empty.");
+        }
+    }
+}
\ No newline at end of file
diff --git a/Detective.java b/Detective.java
index 5707416..331e7b2 100644
--- a/Detective.java
+++ b/Detective.java
@@ -1,35 +1,45 @@
- 
+
 import java.util.ArrayList;
 
 class ToDos {
-    
+
   public static void main(String[] args) {
-    
+
     // Sherlock
     ArrayList<String> sherlocksToDos = new ArrayList<String>();
-    
+
     sherlocksToDos.add("visit the crime scene");
     sherlocksToDos.add("play violin");
     sherlocksToDos.add("interview suspects");
     sherlocksToDos.add("solve the case");
     sherlocksToDos.add("apprehend the criminal");
-    
+
     // Poirot
     ArrayList<String> poirotsToDos = new ArrayList<String>();
-    
+
     poirotsToDos.add("visit the crime scene");
     poirotsToDos.add("interview suspects");
     poirotsToDos.add("let the little grey cells do their work");
     poirotsToDos.add("trim mustache");
     poirotsToDos.add("call all suspects together");
     poirotsToDos.add("reveal the truth of the crime");
-    
+
     // Print the size of each ArrayList below:
+    int a = sherlocksToDos.size();
+    System.out.println("Sherlock's : " + a);
+
+    int b = poirotsToDos.size();
+    System.out.println("Poirot's : " + b);
 
-    
-      
     // Print the name of the detective with the larger to-do list:
-    
+    if (a > b) {
+      System.out.println("Sherlock");
+    } else if (a < b) {
+      System.out.println("Poirot");
+    } else {
+      System.out.println("Sherlock and Poirot");
+    }
+
   }
-  
+
 }
diff --git a/HashCollisionChecker.java b/HashCollisionChecker.java
index 80631a7..5bf520b 100644
--- a/HashCollisionChecker.java
+++ b/HashCollisionChecker.java
@@ -2,13 +2,29 @@
 
 public class HashCollisionChecker {
     public static <T> int countOfUniqueHashCodes(HashSet<T> set) {
-        // TODO: Implement
-        return 0;
+        HashSet<Integer> h_c = new HashSet<>();
+
+        for (T element : set) {
+            int hashCode = element.hashCode();
+            if (!h_c.contains(hashCode))
+                h_c.add(hashCode);
+
+        }
+
+        return h_c.size();
     }
 
     public static <K, V> int countOfUniqueHashCodes(HashMap<K, V> map) {
-        // TODO: Implement
-        return 0;
+        HashSet<Integer> h_c = new HashSet<>();
+
+        for (K key : map.keySet()) {
+            int hashCode = key.hashCode();
+
+            if (!h_c.contains(hashCode))
+                h_c.add(hashCode);
+
+        }
+        return h_c.size();
     }
 
     public static void main(String[] args) {
diff --git a/Shuffle.java b/Shuffle.java
new file mode 100644
index 0000000..19c74f2
--- /dev/null
+++ b/Shuffle.java
@@ -0,0 +1,24 @@
+import java.util.Collections;
+import java.util.LinkedList;
+
+public class Shuffle {
+    public static void main(String[] args) {
+
+        LinkedList<Integer> linkedList = new LinkedList<>();
+        linkedList.add(1);
+        linkedList.add(2);
+        linkedList.add(3);
+        linkedList.add(4);
+        linkedList.add(5);
+
+        System.out.println(linkedList);
+
+        shuffleLinkedList(linkedList);
+
+        System.out.println(linkedList);
+    }
+
+    public static void shuffleLinkedList(LinkedList<Integer> linkedList) {
+        Collections.shuffle(linkedList);
+    }
+}
\ No newline at end of file
diff --git a/Uni.java b/Uni.java
new file mode 100644
index 0000000..0203932
--- /dev/null
+++ b/Uni.java
@@ -0,0 +1,88 @@
+import java.util.*;
+
+class Student implements Comparable<Student> {
+    private String name;
+    private String studentId;
+    private double gpa;
+
+    public Student(String name, String studentId, double gpa) {
+        this.name = name;
+        this.studentId = studentId;
+        this.gpa = gpa;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getStudentId() {
+        return studentId;
+    }
+
+    public double getGpa() {
+        return gpa;
+    }
+
+    @Override
+    public int compareTo(Student other) {
+        return this.studentId.compareTo(other.studentId);
+    }
+
+    @Override
+    public String toString() {
+        return "Name: " + name + ", ID: " + studentId + ", GPA: " + gpa;
+    }
+}
+
+public class Uni {
+
+    private static TreeSet<Student> studentSet = new TreeSet<>();
+
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+
+        while (true) {
+            System.out.println("\nMenu:");
+            System.out.println("1. Add Student");
+            System.out.println("2. Search Student by ID");
+            System.out.println("3. Exit");
+
+            int choice = scanner.nextInt();
+            scanner.nextLine();
+
+            switch (choice) {
+                case 1:
+                    System.out.println("Enter student's name:");
+                    String name = scanner.nextLine();
+                    System.out.println("Enter student's ID:");
+                    String studentId = scanner.nextLine();
+                    System.out.println("Enter student's GPA:");
+                    double gpa = scanner.nextDouble();
+                    Student student = new Student(name, studentId, gpa);
+                    studentSet.add(student);
+                    System.out.println("Student added successfully.");
+                    break;
+                case 2:
+                    System.out.println("Enter student's ID to search:");
+                    String idToSearch = scanner.nextLine();
+                    boolean found = false;
+                    for (Student s : studentSet) {
+                        if (s.getStudentId().equals(idToSearch)) {
+                            System.out.println("Student found: " + s);
+                            found = true;
+                            break;
+                        }
+                    }
+                    if (!found) {
+                        System.out.println("Student not found.");
+                    }
+                    break;
+                case 3:
+                    System.out.println("Exiting...");
+                    return;
+                default:
+                    System.out.println("Invalid choice. Please enter 1, 2, or 3.");
+            }
+        }
+    }
+}
\ No newline at end of file