product except self today

Author: LEUNGUU

src/product_except_self.py

@@ -0,0 +1,17 @@
+from typing import List
+
+
+class Solution:
+    def productExceptSelf(self, nums: List[int]) -> List[int]:
+        res = [1] * len(nums)
+
+        prefix = 1
+        for i in range(len(nums)):
+            res[i] = prefix
+            prefix *= nums[i]
+
+        postfix = 1
+        for i in range(len(nums) - 1, -1, -1):
+            res[i] *= postfix
+            postfix *= nums[i]
+        return res

tests/test_product_except_self.py

@@ -0,0 +1,10 @@
+from product_except_self import Solution
+
+testcases = [{"testcase": [1, 2, 3, 4], "result": [24, 12, 8, 6]}]
+
+
+def test_product_except_self():
+    for tc in testcases:
+        nums = tc["testcase"]
+        ans = Solution().productExceptSelf(nums)
+        assert ans == tc["result"]