Here's and Unofficial Editorial for the problems- A - You just need to find if a subsequence of numbers is divisible by 3 or not. For this, convert each element of arr to arr [i]%3.

No Valid Subsequence: If no subsequence satisfies the divisibility rule, return an empty sequence. Input and Output Input: A sequence of integers (stone values). Example: [2, 3, 5, 1, 4, 7] Output: ...