diff --git a/src/CommonElementsFinder.java b/src/CommonElementsFinder.java
index fb88a4b..f8775bb 100644
--- a/src/CommonElementsFinder.java
+++ b/src/CommonElementsFinder.java
@@ -1,3 +1,4 @@
+import java.util.HashSet;
 import java.util.Set;
 
 /**
@@ -14,8 +15,16 @@ public class CommonElementsFinder {
      * @return a Set<Integer> containing the integers that are present in both arrays
      */
     public static Set<Integer> findCommonElements(int[] array1, int[] array2) {
-        // TODO
-        return null;
+        Set<Integer> set1 = new HashSet<>();
+        for (int i: array1) {
+            set1.add(i);
+        }
+        Set<Integer> commonSet = new HashSet<>();
+        for (int i: array2) {
+            if (set1.contains(i)) commonSet.add(i);
+        }
+        
+        return commonSet;
     }
 
 
diff --git a/src/DuplicateRemover.java b/src/DuplicateRemover.java
index 8d70003..f1bcb48 100644
--- a/src/DuplicateRemover.java
+++ b/src/DuplicateRemover.java
@@ -1,4 +1,7 @@
+import java.util.ArrayList;
 import java.util.List;
+import java.util.Set;
+import java.util.TreeSet;
 
 /**
  * The DuplicateRemover class provides a method to remove duplicate words
@@ -14,8 +17,15 @@ public class DuplicateRemover {
      * @return a sorted List<String> containing unique words from the input array
      */
     public static List<String> sortAndRemoveDuplicates(String[] words) {
-        // TODO
-        return null;
+        Set<String> unique = new TreeSet<>();
+        for (String word: words) {
+            unique.add(word);
+        }
+        List<String> wordList = new ArrayList<>();
+        for (String word: unique) {
+            wordList.add(word);
+        }
+        return wordList;
     }
 
     public static void main(String[] args) {
diff --git a/src/UniqueCharacterChecker.java b/src/UniqueCharacterChecker.java
index 554ffc4..7b49d90 100644
--- a/src/UniqueCharacterChecker.java
+++ b/src/UniqueCharacterChecker.java
@@ -1,3 +1,6 @@
+import java.util.HashSet;
+import java.util.Set;
+
 /**
  * The UniqueCharacterChecker class provides a method to check if all characters
  * in a given word are unique.
@@ -14,7 +17,11 @@ public static boolean hasUniqueCharacters(String word) {
         // TODO: implement this!
         // Requirement: This must run in O(n) time, where n is the number of characters in the word
         // Hint: Stuck? Consider looking up "charAt" and seeing how it can help you
-        return false;
+        Set<Character> charSet = new HashSet<>();
+        for (char c: word.toCharArray()) {
+            charSet.add(c);
+        }
+        return charSet.size() == word.length();
     }
 
     public static void main(String[] args) {