238. Product of Array Except Self

[stada526]

Problem Link

https://leetcode.com/problems/product-of-array-except-self/description/

Solution

One immediate approach is to calculate the product of all elements in nums, and then divide this product by each element at index i to obtain the result.
For example, if nums is [2,3,4], the total product is 2 * 3 * 4 = 24. Dividing this product by each element gives [24/2, 24/3, 24/4] = [12, 8, 6].
This solution operates in O(n) time complexity, but division is not allowed in this problem.

Therefore, another approach can be considered.
In this approach, for each index i in nums, we calculate the product of all elements before i (from 0 to i-1) and the product of all elements after i (from i+1 to the end).
Finally, we multiply these two products together to get the desired result, which is the product of all elements expect for nums[i].