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].
The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer.
You must write an algorithm that runs in O(n) time and without using the division operation.
Example 1:
Input: nums = [1,2,3,4]
Output: [24,12,8,6]
Example 2:
Input: nums = [-1,1,0,-3,3]
Output: [0,0,9,0,0]
Python Solution
class Solution:
def productExceptSelf(self, nums: List[int]) -> List[int]:
prod_array = [1] * len(nums)
# Prefix
prefix = 1
for i in range(len(nums)):
prod_array[i] = prefix
prefix *= nums[i]
# Postfix
postfix = 1
for i in range(len(nums)-1,-1,-1):
prod_array[i] *= postfix
postfix *= nums[i]
return prod_array