✅ product of array except self

Arrays and Hashing/Product of Array Except Self.py

@@ -12,7 +12,40 @@
 
 class Solution:
     def productExceptSelf(self, nums):
-        return nums
+        # brute force 1
+        """
+        make a new array
+        Iterate throw the threw the nums array and append product of all nums element except the current indexed element
+
+        the problem with this solution is, it is not optimized and in O(n^2) we need O(n)
+        doesn't work on [0,0]
+        """
+        # answer_list = []
+        # for i in nums:
+        #     product = 1
+        #     for j in range(len(nums)):
+        #         if i != nums[j]:
+        #             product *= nums[j]
+        #     answer_list.append(product)
+        # return answer_list
+        """
+        to make the solution in O^
+        """
+        n = len(nums)
+        left_products = [1] * n
+        right_products = [1] * n
+        new_array = [1] * n
+
+        for i in range(1, n):
+            left_products[i] = left_products[i - 1] * nums[i - 1]
+
+        for i in range(n - 2, -1, -1):
+            right_products[i] = right_products[i + 1] * nums[i + 1]
+
+        for i in range(n):
+            new_array[i] = left_products[i] * right_products[i]
+
+        return new_array
 
 
 s = Solution()
@@ -23,11 +56,5 @@ def productExceptSelf(self, nums):
 # Example 2
 print(s.productExceptSelf([-1, 1, 0, -3, 3]))  # [0,0,9,0,0]
 
-
-def triangle(size):
-    for i in range(size):
-        print("* " * (i + 1))
-
-
-size = 5
-triangle(size)
+# Example 3
+print(s.productExceptSelf([0, 0]))  # [0,0]