diff --git a/Top150Interview/217_Contains_Duplicate.py b/Top150Interview/217_Contains_Duplicate.py
index 2800c4c..d594d9e 100644
--- a/Top150Interview/217_Contains_Duplicate.py
+++ b/Top150Interview/217_Contains_Duplicate.py
@@ -3,13 +3,16 @@ def containsDuplicate(nums):
     :type nums: List[int]
     :rtype: bool
     """
-    dupes = []
+    # Single pointer, time limit exceeded FIXED
+    dupes = set()
     for x in nums:
-        if x not in dupes:
-            dupes.append(x)
-        else:
+        if x in dupes:
             return True
+        dupes.add(x)
     return False
 
-
-containsDuplicate([1,2,3,1])
\ No newline at end of file
+print(containsDuplicate([1,2,3,1]))
+print(containsDuplicate([1,2,3,4]))
+print(containsDuplicate([1,1,1,3,3,4,3,2,4,2]))
+print(containsDuplicate([1000000000,1000000000,11]))
+print(containsDuplicate([1,5,-2,-4,0]))
\ No newline at end of file