Coding challenge: clique problem

Recently I’ve been researching the maximum clique problem and found a couple of interesting algorithms for it. The easiest to implement is the Bron-Kerbosch algorithm, that uses recursive backtracking to list all maximal cliques in an arbitrary graph. (https://en.m.wikipedia.org/wiki/Bron–Kerbosch_algorithm) It is pretty efficient for an algo that short. I propose a coding challenge about this algorithm.

PS: I’d love to see more coding challenges on NP hard problems.