I found a (trivial) solution to my problem after submitting it

Question

About Counting primes in a range whose digits are all prime.

My code had a bug, the bug was an edge case that only manifested in literally one of the test cases, (I identified it by completing the problem with linear search, then downloading the test cases and then working through them to figure out which one broke it). The answer: Due to me misinterpreting/misremembering the bound, I used > instead of >= when checking for values above the upper bound, which led to an infinite loop (somehow, I didn't get as far as figuring out how exactly the wrong bounds check caused my problem).

My code has no answers yet, and is unlikely to get any answers (unless someone goes through the same process as I do to figure out the edge case that broke it/someone wizzy enough to connect binary search timing out with an infinite loop, and identify what caused the infinite loop checks out the problem), so I'm wondering if I should delete my question or answer it. The reasons I didn't auto answer are:

1. The question has no upvotes (or downvotes), comments (or even views) by other users or answers as of now, so deleting it wouldn't have much of an impact.
2. The problem was a very niche, very specific problem and may not generalise well. Stack Overflow wants solutions to be broadly applicable and helpful to future programmers who encounter your breed of problem. This isn't SO (in retrospect my question is probably a better fit for SO all things considered, and if I knew the cause I would have posted it to SO, but if I knew the cause I would have fixed it, so it's moot), but I thought it's a sensible policy.

I didn't auto delete because I'd rather not delete my content than do so ceteris paribus, and because site policy may want me to keep my content here? So I decided to ask around here.

Answer 1

My code had a bug

Usually code has to work as intended before it's ready for review. However, since the bug wasn't know at time of writing and a time-out can be caused by plenty of other things that don't necessarily disqualify the question, it's not a problem here.

My code has no answers yet, and is unlikely to get any answers

Probably thanks to the meta effect, somebody noticed your question and wrote an answer for it anyway. Keep in mind, your question wasn't that old when it got posted. On Code Review, it's not unheard of for the first answer to arrive 2 whole days after the question got posted. Writing a review can take a lot of time and often enough people notice the question first and start writing an answer only after thinking about it for a while first. Be patient.

I'm wondering if I should delete my question or answer it.

There's no reason to delete it, but if you were no longer looking for a review, I can understand why you would remove it. A self-answer containing a review would be perfectly fine too.

The question has no upvotes (or downvotes), comments (or even views) by other users or answers as of now, so deleting it wouldn't have much of an impact.

True.

The problem was a very niche, very specific problem and may not generalise well.

That's not a problem at Code Review, I've seen some very niche questions here that got answered regardless.

site policy may want me to keep my content here?

Site policy wants to you keep your questions if they are answered. If they are not, there is no policy against removing them.

In this situation, you really couldn't have gone wrong. All your suggested options seem acceptable in this case.