It's not -- the Reddit thread has a counterexample: https://www.reddit.com/r/adventofcode/comments/a8s17l/2018_day_23_solutions/ecdxr1u/ https://www.reddit.com

It's not -- the Reddit thread has a counterexample: https://www.reddit.com/r/adventofcode/comments/a8s17l/2018_day_23_solutions/ecdxr1u/ https://www.reddit.com/r/adventofcode/comments/a8s17l/2018_d... That said -- one visualization posted elsewhere showed that that person's particular input was a bunch of singletons, plus one colossal clique that all intersected at a single point. That may have been structure that people were meant to discover -- but it's not clear that anyone did until after the fact. (The person with the visualization identified the clique as all the "bot ranges" intersecting with a solution point that they'd already found by other means.)