find common items

Author: ebrahimbeiati

Sprint-1/Python/find_common_items/find_common_items.py

@@ -9,13 +9,22 @@ def find_common_items(
     """
     Find common items between two arrays.
 
-    Time Complexity:
-    Space Complexity:
-    Optimal time complexity:
+    Time Complexity: O(n * m)
+    Space Complexity: O(n)
+    Optimal time complexity: O(n + m)
+    Explanation: The function uses a nested loop to check every possible pair of items in the two
+    sequences to see if they are common.
+    This results in a time complexity of O(n * m).
+    Using a set for constant-time lookups can reduce the time complexity to O(n + m)
+    by first converting one of the sequences into a set and then checking for common items in a single loop.
     """
-    common_items: List[ItemType] = []
-    for i in first_sequence:
-        for j in second_sequence:
-            if i == j and i not in common_items:
-                common_items.append(i)
-    return common_items
+    lookup = set(second_sequence)
+    result = []
+    seen = set()
+
+    for item in first_sequence:
+        if item in lookup and item not in seen:
+            seen.add(item)
+            result.append(item)
+
+    return result