LeetCode 238 Product of Array Except Self - Prefix and Suffix

Think about what "all elements except $i$" means. It's all elements to the left of $i$ times all elements to the right of $i$. Build two arrays:

$1.$ $prefix[i]$ = product of all elements before index $i$

$2.$ $suffix[i]$ = product of all elements after index $i$ Then $answer[i] = prefix[i] \times suffix[i]$. You're using the same "precompute to answer in $O(1)$" idea, but with products instead of sums, and in both directions.