yup, still can't make sense of it after understanding the solutions.

What do m and s even represent?

past or present denominators, or defaults

If the value before the most recent left choice was l/m and the value before the most recent right choice was r/s then the new value will be (l+r) / (m+s).

That line, paraphrased / decoded / whatever:

(l+r)/(m+s) is each new fraction (next iteration), before substitution and simplification. Let l/m represent whatever the fraction was, just before you most recently parsed an L choice. Let r/s represent whatever the fraction was, just before you most recently parsed an R choice.

This is how values of l, r, m, s are obtained most often. But l = 1, r = 0, m = 0, s = 1 are defaults, used when there is no previously parsed L or R (or neither, as shown in the way that the initial 1/1, corresponding to the empty string, is formed entirely out of them).

HTH

Same here, I took my notebook and wrote the numbers, the fractions, tried to find a pattern but nothing. I'm not quite following the explanation, this is a problem that most likely would be solved in lets say 10-15 lines maybe, but man I can't even find the logic. If someone can explain it I would appreciate it a lot.

javascript translation added and made description language-agnostic

approved some while ago

Clever, but this code is less readable than if you split it into several functions with explicit names.

this image should really be in the description

Yesn't, Char is an instance of Ord where the characters are ordered by their unicode codepoint. It does not really "threat them as they were numbers" but deep down at some point everything is an int eventually.

wait, Haskell treats chars the same way as if they were numbers? like, he automatically converts char to number like ord() in python?

python new test framework is required. updated in this fork

And now I know about the sorted() function...I love it.

nice, never knew this concept.

So interesting solution

nice code, clean :)