# 238. Product of Array Except Self 壓縮前: ```python= class Solution: def productExceptSelf(self, nums: List[int]) -> List[int]: accum = 1 res = [1 for _ in range(len(nums))] for i in range(1, len(nums)): accum *= nums[i-1] res[i] *= accum accum = 1 for i in range(len(nums)-2, -1, -1): accum *= nums[i+1] res[i] *= accum return res ``` 壓縮後: ```python= class Solution: def productExceptSelf(self, nums: List[int]) -> List[int]: accum1, accum2 = 1, 1 res = [1 for _ in range(len(nums))] for i in range(1, len(nums)): accum1 *= nums[i-1] res[i] *= accum1 accum2 *= nums[len(nums) - i] res[len(nums) - i - 1] *= accum2 return res ```