I like it so far.
Task 3 was basically about simple iterating.
Task 4 can be solved using state machine, though data validation in hard part was a little bit hectic(missed java/kotlin spring validation thingy), so I wrote quite a number of unit tests.
Task 5, as title ‘Binary boarding’ suggests, is about using binary search algorithm, a few times.
Task 6 reminds me task 4, but was somewhat easier to my taste.

For some reasons wrote it all in Ruby. IDE autocompletion feels strange, sometimes up to non-existent.
But I enjoy the process, and the result as well.