use set to remove duplicates

Author: aydaeslami

Sprint-1/Python/remove_duplicates/remove_duplicates.py

@@ -8,18 +8,28 @@ def remove_duplicates(values: Sequence[ItemType]) -> List[ItemType]:
     Remove duplicate values from a sequence, preserving the order of the first occurrence of each value.
 
     Time complexity:
+        ANSWER: O(n)
+        Because the sequence is looped through once.
+
     Space complexity:
+        ANSWER: O(n)
+        Because a set is used to track seen value
+
+
     Optimal time complexity:
+        ANSWER: O(n)
+        Each value is processed once using a set for faster lookup
+        
     """
     unique_items = []
+    seen = set()
+
 
     for value in values:
-        is_duplicate = False
-        for existing in unique_items:
-            if value == existing:
-                is_duplicate = True
-                break
-        if not is_duplicate:
+        if value not in seen:
+            seen.add(value) 
+
             unique_items.append(value)
+       
 
     return unique_items