You should keep internal state of your class hidden to the user. My solution should not pass, I guess. Alternatively, don't use classes and just provide a string and expect an array as result.

you should change the wording about the content of "cells": in the bullet points, you're talking all the time about "values", while you're using sort of "enums"/constante (EMPTY/FILLED) It's a bit confusing (mostly because your setup is somewhat overthought, imo)

Hi,

It's not clear what the result should be: is the PicrossClues class already implemented? (looking a the initial solution, it seems so => just say it in the description).

Why a class while a simple object {rows:...,columns:...} could have been enough?