Week 2

Author: 8804who

product-of-array-except-self/8804who.py

@@ -1,17 +1,26 @@
 class Solution:
     def productExceptSelf(self, nums: List[int]) -> List[int]:
-        total_product = 1
+        answer = []
 
-        for num in nums:
-            if num != 0:
-                total_product *= num
-        
-        if nums.count(0) == 1:
-            return [0 if num != 0 else total_product for num in nums]
-        elif nums.count(0) > 1:
-            return [0 for _ in range(len(nums))]
-        else:
-            return [total_product//num for num in nums]
-    
+        product1 = [0] * len(nums)
+        product2 = [0] * len(nums)
+
+        product1[0] = nums[0]
+
+        for i in range(1, len(nums)):
+            product1[i] = product1[i-1]*nums[i]
 
+        product2[-1] = nums[-1]
 
+        for i in range(len(nums)-2, -1, -1):
+            product2[i] = product2[i+1] * nums[i]
+
+        for i in range(len(nums)):
+            if i == 0:
+                answer.append(product2[1])
+            elif i == len(nums)-1:
+                answer.append(product1[-2])
+            else:
+                answer.append(product1[i-1]*product2[i+1])
+        return answer
+