This kata is a duplicate of https://www.codewars.com/kata/583daf5f8bbc0446f50002d0 (which was removed due to copyright infringement)

Too many tests for a non-performance kata ( this should be 7 kyu, right? ).

100 reasonably sized tests is more than adequate, and should run in milliseconds, for a much better user experience.

Unfortunately, the task itself is very close to things that already exist,

Check if s is formed by the first character the first part (one or more chars) of each word. E.g.

['alice','bob','charlie'], 'alboc'  ->  True

P.S. I don't know if it is already done.

https://www.codewars.com/kata/reviews/64f32eead313d9003e9ca5d6/groups/64f33a3b96b3d100011c91c5

• Needs restricted flag (you are banning at least bisect)
• Description should also mention that builtin libraries are restricted

I feel the hint you provided is a bit on the nose.
This is an interesting little puzzle...
Maybe a hint that's less significant might make the solve more enjoyable.

Also, keep in mind that different languages have different ways of expressing binary, and 0b01101 in Python will be 01101 in javascript, e.g., which could make future translations problematic.
Just my ¢2 ...

• no random tests
• no solution setup
• duplicate
• too much basic
• asking for a builtin has generally close to no interest

cheers