I had to search the original publication to see what kind of computer cluster they used. Here it is in case you are curious: "We ran all three experiments

I had to search the original publication to see what kind of computer cluster they used. Here it is in case you are curious: "We ran all three experiments simultaneously on 20 nodes on the Lonestar5 cluster and computing on 24 CPUs per node in parallel." It seems it took less than an hour. I think that calling it a "fleet of computers" is a little too much. It makes it look like they brute-forced the problem while the truth is that as usually the merit was on the algorithm.