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]Constraints:
2 <= nums.length <= 105
-30 <= nums[i] <= 30
The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer.Iterate through the array with two pointers, where we multiply the left side by the left pointer, and the right side by the right pointer.
class Solution:
def productExceptSelf(self, nums):
res = [1] * len(nums)
lprod = 1
rprod = 1
for i, num in enumerate(nums):
res[i] *= lprod
lprod *= num
res[~i] *= rprod
rprod *= nums[~i]
return res