It was like SUPER late when I attempted the problem and I was not at my best. I know all about base-types and numerical expressions.
I was just being stupid. I got some help via discord and ended up getting to a solution that, while clunky, helped to teach me some fundamentals.
I put an EXTENSIVE comment suite in the solution that explains my data stream for a sample input. Thanks!

Do you know what are number systems with different bases? Like binary, octal, decimal, hexadecimal?
Do you know what are imaginary numbers, complex numbers, and imaginary unit i?

There are two ways to solve this kind of problems:

• research relevant topics, like the two I mentioned above, or
• leave the kata for now, and forget it, or come back to it after getting better grasp of maths behind it.

I am pretty new to coding and do not really know what to do with a problem that is basically pure maths like this. What does that last block mean [a, b] = a+b*i? What is my output actually supposed to look like? If I am given a string with some number like 101 (one hundred one) and...is that not ALREADY in base 10 form? I am very confused. Could I have some clarification? Thanks!