Actually I gave up on that approach and found a new one that requires me to concatenate the result of a train with an earlier result of the same train. Is that even possible without storing to a variable?
@Adám I just noticed there's a constraint to the challenge that you need to output a string or a single integer, not a list of digits. How do I turn a vector of digits into a single string or number?
(⊢,11|(+/⊢×⍳∘≢))3↓¯1↓⍎¨'<arg_as_string>' is the current code
ah, I can do 10⊥(⊢,11|(+/⊢×⍳∘≢))3↓¯1↓⍎¨
Is there a better way?
Actually that doesn't work because it removes leading zeroes D:
