I'm not complaining about this solution at all -- it's clever and effective -- but I still find it a bit sad that it has more votes than the solution that's both simpler and almost 40x faster.

This can't really be best practice with how many extra strings get unnecessarily created with each recursive call.

it is short but very suboptimal unfortunately - this forces unnecessary calcualtion of square number... if the array is large then it is very inefficient. Manual squre is the way as it allows to return false if the first one or any is false, rather than doing all the calculations beforehand.

using modulo is slower than testing the LSB.

I think this solution is actually smart, good work

Просто лучший!

Please use spoiler flag next time.

Understand the wrong question and make the initial scheme complicated. Returns a string showing the power of the power and the entire equation process.

Nice !

Ok, what about this note?

it may happen that the input string have leading, trailing whitespaces and more than a unique whitespace between two consecutive numbers