add productofarrayexceptself py

Author: kumailn

Python/Product_of_Array_Except_Self.py

@@ -0,0 +1,34 @@
+#Question: Given a list of numbers, multiply each number by all other numbers except itself
+#Solution: Traverse right then left while multiplying
+#Difficulty: Medium
+#Time Complexity: O(n)
+#Space Complexity: O(n)
+
+from typing import List
+
+def productExceptSelf(nums: List[int]) -> List[int]:
+    #Initialize a variable to store the current multiplication, and one to store the result
+    multiplier, result = 1, [1] * len(nums)
+
+    #Loop through forwards
+    for i, v in enumerate(nums):
+
+        #Set the ith index to be the multiplier, and multiply the multiplier by the current number
+        result[i] *= multiplier
+        multiplier *= v
+
+    #Reset the multiplier
+    multiplier = 1
+    
+    #Loop through backwards doing the same thing
+    for i, v in reversed(list(enumerate(nums))):
+        result[i] *= multiplier
+        multiplier *= v
+    
+    return result
+
+
+def main():
+    print(productExceptSelf([1, 2, 3, 4]))
+    print(productExceptSelf([4,3,2,1,2]))
+main()