have you seen the comment in the initial code ?

(* uncomment if you need it: open Z;;
input of find_nb is a string representing a big integer *)

you can use the Zarith library, which is the official big integers library for OCaml. this makes the OCaml version not much harder than the other languages

Hi,

According to the specs of the unlock method, the case you suggested should result in an EmptyMoleculeError because when you unlock the molecule, there is no branch anymore. There should be a fixed test about that, iirc.

• Are you trying the sample tests or the full test suite (aka, "tests" vs "attempt" button)?
• what language are you using? (looks like it's python?)