@l3kn @cancel I did this in the end. Had to look up the theorem. Not sure I'm a fan of this kind of task for AoC.

@l3kn yeah I never would have figured that out on my own

@l3kn oh yeah, you're still participating. I *do* recognize you :)

@l3kn I read a little bit of that page, then stopped, and tried to figure it out again, but I still can't get it. What am I doing wrong? This works for all of the examples, but never terminates for the real input https://gist.github.com/randrew/c7fa048f0079fa6058853f076221da7a

any hint?

@cancel @l3kn seems like you can just do (d+id)%id and the result will be the wait time for that bus to depart.

@shironeko @l3kn that doesn't use 'm' in the loop, so it will never terminate

@cancel @l3kn yeah, I'm saying you can calculate m directly.

@shironeko @l3kn that seems to give nonsense results

@cancel @l3kn hmm, I took a closer look at the code, it seems to be doing something different than what I had in mind (from reading the question)

@cancel @l3kn what I had in mind:
for each id, calculate wait time (arrival timestamp + id) % id , if it's smaller than the current minimum, update the current minimum. at the end, output the answer.

@shironeko @l3kn did you do day 13? is that how yours' works?

@cancel @l3kn okay, I just joined, and got my answer accepted. minor hiccup. it was actually (id- arrival timestamp) % id. lol I messed up the sign.

@shironeko @l3kn

Num m = (id - t) % id;
?
that doesn't give correct results.

@cancel @l3kn well, you are doing it in a completely different way, so that's to be expected.

@shironeko @l3kn you're replying to a thread where I posted my code. I didn't know we were talking about something else?

@shironeko @l3kn Sorry, I'm not trying to be rude. I'm genuinely confused about what's going on here.

@cancel @l3kn > what I had in mind:
> for each id, calculate wait time (arrival timestamp + id) % id , if it's smaller than the current minimum, update the current minimum. at the end, output the answer.

it was for this algorithm. I'm still reading your code trying to figure out how you intended to do it, maybe explain it a little bit?

@shironeko @l3kn I don't really have an intuition for how it works. I just permuted multiplying and adding things together, and this happens to give correct answers for the example inputs.

@shironeko @l3kn I jiggled the terms around more, after someone else told me to, and now it works for the real input.

@cancel @shironeko I had a similar problem where the offset (`i` in your program) was larger than the modulus (`id`), fixed it by using `i % id` as the offset.

@l3kn @shironeko yup

@cancel (I'm agarciamontoro in the leaderboard, btw)