Hi, I believe on the USACO training site there was a problem that was to solve 8 queens but in a very, very tight time limit. So you had to keep optimizing first with simple stuff but then with symmetries and so on.
I never was able to get that under the time limit, it was many years ago, and I left the USACO site.
Now I thought of that problem again and was interested in trying it. I re-logged in to train.usaco.org after many years and my "DONE" and viewed problems are showing but I cannot find this one. I'm 90% sure it was at USACO and nowhere else.
Does anybody know the problem statement I'm talking about? Do you know if it's been removed from USACO? Thanks!
I'm not sure about it being on USACO, but what you're describing sounds like this UVa problem.
It's basically n-queens but n ≤ 15, so you had to exploit many strategies to really squeeze the runtime.