238. Product of Array Except Self

Given an array nums of n integers where n > 1, return an array output such that output[i] is equal to the product of all the elements of nums except nums[i].

Example:

Input:  [1,2,3,4]
Output: [24,12,8,6]

Constraint: It's guaranteed that the product of the elements of any prefix or suffix of the array (including the whole array) fits in a 32 bit integer.

Note: Please solve it without division and in O( n ).

Follow up: Could you solve it with constant space complexity? (The output array does not count as extra space for the purpose of space complexity analysis.)

# @lc code=start
using LeetCode

function product_except_self(nums::Vector{Int})
    n = length(nums)
    left = right = 1
    res = fill(1, n)
    @inbounds for i in 1:n
        res[i] *= left
        left *= nums[i]
        res[n - i + 1] *= right
        right *= nums[n - i + 1]
    end
    return res
end
# @lc code=end

product_except_self (generic function with 1 method)

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