product of array except self solution

Author: jylee2033

product-of-array-except-self/jylee2033.py

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+class Solution:
+    def productExceptSelf(self, nums: List[int]) -> List[int]:
+        # answer[i] = product up to i * product from i
+
+        n = len(nums)
+
+        prefix_product = [1] * n
+        suffix_product = [1] * n
+
+        for i in range(1, n):
+            prefix_product[i] = prefix_product[i-1] * nums[i-1]
+
+        for i in range(n - 2, -1, -1):
+            suffix_product[i] = suffix_product[i + 1] * nums[i + 1]
+
+        answer = [1] * n
+        for i in range(n):
+            answer[i] = prefix_product[i] * suffix_product[i]
+
+        return answer
+
+# Time complexity: O(n)
+# Space complexity: O(n)