Given an integer array nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i]. You must write an algorithm that runs in O(n) time and without using the division operation.
2 <= nums.length <= 10^5, -30 <= nums[i] <= 30, The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer
Use prefix and suffix products. For each index, multiply the product of all elements to the left by the product of all elements to the right.
def productExceptSelf(nums):
n = len(nums)
result = [1] * n
prefix = 1
for i in range(n):
result[i] = prefix
prefix *= nums[i]
suffix = 1
for i in range(n - 1, -1, -1):
result[i] *= suffix
suffix *= nums[i]
return result