Add solution for neetcode: products of array except self

neetcode/arrays/products_of_array_except_self/README.md

@@ -0,0 +1,21 @@
+Given an integer array nums, return an array output where output[i] is the product of all the elements of nums except nums[i].
+
+Each product is guaranteed to fit in a 32-bit integer.
+
+Follow-up: Could you solve it in O (n)
+O(n) time without using the division operation?
+
+Example 1:
+
+Input: nums = [1,2,4,6]
+
+Output: [48,24,12,8]
+Example 2:
+
+Input: nums = [-1,0,1,2,3]
+
+Output: [0,-6,0,0,0]
+Constraints:
+
+2 <= nums.length <= 1000
+-20 <= nums[i] <= 20

neetcode/arrays/products_of_array_except_self/products_of_array_except_self.py

@@ -0,0 +1,39 @@
+from typing import List
+import pytest
+
+
+class Solution:
+    def productExceptSelf(self, nums: List[int]) -> List[int]:
+        if not nums:
+            return []
+        res = []
+        while len(res) != len(nums):
+            for i in range(0, len(nums)):
+                j = 0
+                tmp = 0
+                for j in range(0, len(nums)):
+                    if i == j:
+                        continue
+                    if j == 0:
+                        tmp = nums[j]
+                        continue
+                    if j == 1 and i == 0:
+                        tmp = nums[j]
+                        continue
+                    tmp *= nums[j]
+                res.append(tmp)
+        return res
+
+
+@pytest.mark.parametrize(
+    "input_value, expected_value",
+    [
+        ([1, 2, 4, 6], [48, 24, 12, 8]),
+        ([-1, 0, 1, 2, 3], [0, -6, 0, 0, 0]),
+        ([], []),
+        ([-1, 1, 0, -3, 3], [0, 0, 9, 0, 0]),
+    ],
+)
+def test_solution(input_value, expected_value):
+    s = Solution()
+    assert s.productExceptSelf(nums=input_value) == expected_value