In the particular project I was talking about (see https://inst.eecs.berkeley.edu/~cs170/sp20/assets/project/sp... for a similar project) a solution is to reduce the problem to SAT and feed it into a SAT solver. Outside of the project, we were also taught the other way around (demonstrate NP-hardness). See https://people.eecs.berkeley.edu/~vazirani/algorithms/chap8.....