I Applied the same But it falis and have to check if the factor == 0 or not at the first before mod operation

if factor == 0 {
    return false
}
return (base % factor) == 0

Awesome use of the REX prefix! Nice way to use NOP to form UTF8.

Use spoiler flag next time, please. Your post was visible in the homepage.

wow! I used to do that with powershell to batch but I never thought of this very clever!

I folded in the wrong direction earlier, should have done this for early exiting. (I can't just quickly imagine the evaluation order without doing it step by step on paper, but, whatever the reason is, this version is faster. Maybe it's just the usual stricter evaluation thing.)

Those "biased random tests" are about the worst case I could think of.

The "more biased tests" effectively punish denseness, though their design purpose was to punish DFS solutions in favour of BFS ones.

Is there a way to usefully specify a distribution without completely slipping into into technicalities? Generally, the target is somewhere in the possible range, though there is never a guarantee it can be made exactly from the available numbers. But I already say that.

Another thing is too much laziness, all those lists and maybes there, see the other fork.

One thing is there's no early exit here (check the fork).
Input distribution to optimize for isn't specified, so it's unclear if densness is good or bad. It's not slower for the "biased random tests", in which density is always about 100%.

it's not fast though. do dense lists instead of Maps introduce so much overhead, is that the problem?

Invalidated because of changes to testing system: change list to a set in your solution if you wanna have it validated.

when you tried anything and then reading wikipedia taking from it :))

See my second sentence above, I think it answers your question

sorry forgot to share

arr = ['lion', 'monkey', 'lizzard']

please try it also

I am curious if you get the same