Beats 80% of runtime, uses a lot of memory. multiples loops is still O(n)

NeetCodeRoadmap/Arrays_and_Hashing/238_Product_of_Array_Except_Self.py

@@ -1,19 +1,43 @@
-from functools import reduce
-import operator
 
+# from functools import reduce
+# import operator
+
+
+# def productExceptSelf(nums):
+#         """
+#         :type nums: List[int]
+#         :rtype: List[int]
+#         """
+#         final = []
+#         for x in range(len(nums)):
+#                 temp = nums[0]
+#                 del nums[0]
+#                 final.append(reduce(operator.mul, nums))
+#                 # print(nums)
+#                 nums.append(temp)
+#                 # print(final)
+#         return final
+# print(productExceptSelf([1,2,3,4]))
 
 def productExceptSelf(nums):
-        """
+    n = len(nums)
-        :type nums: List[int]
+    prefix_products = [1] * n
-        :rtype: List[int]
+    suffix_products = [1] * n
-        """
+    result = [1] * n
-        final = []
+
-        for x in range(len(nums)):
+    prefix_product = 1
-                temp = nums[0]
+    for i in range(n):
-                del nums[0]
+        prefix_products[i] = prefix_product
-                final.append(reduce(operator.mul, nums))
+        prefix_product *= nums[i]
-                # print(nums)
+
-                nums.append(temp)
+    suffix_product = 1
-                # print(final)
+    for i in range(n - 1, -1, -1):
-        return final
+        suffix_products[i] = suffix_product
-print(productExceptSelf([1,2,3,4]))
+        suffix_product *= nums[i]
+
+    for i in range(n):
+        result[i] = prefix_products[i] * suffix_products[i]
+
+    return result
+
+print(productExceptSelf([1, 2, 3, 4]))