.

7, with a pencil and a paper:

• 0 -> 1 -> 2 -> 3 -> 4 -> 5 -> 6 -> 0
• 0 -> 6 -> 5 -> 4 -> 3 -> 2 -> 1 -> 0

Lets say i have spinningRings(6,6)

is the answer:3 (they just need to be aligned 0)

or

6 (they must align 0 at top)?

You are correct. This was a very naive brute force implementation which, while it passed the tests, was computationally super expensive.

Thanks for the feedback, rewriting this was a nice exercise :)

i think this will perform worse as the number gets bigger.

Yep, 'i' refers to the index of the row as the board is traversed with the 'every' function.
So it's mapping the ith element of each row and passing arrays representing individual columns into checkDigits().

i dunno, but for me using Math.sqrt feels like cheating.

but yeah, in real world we will use this way.

check my solution. What think about that.

You treat this case as empty label ""

Unlike with numbers, the expression of just [terminal] is valid.

if it is valid, how do jumper calls it?

can you describe why this algorithm works?