Something is missing from this discussion. The sample problem in the xkcd comic is from a class of NP-complete problems, but being small, it has a solution in "

Something is missing from this discussion. The sample problem in the xkcd comic is from a class of NP-complete problems, but being small, it has a solution in "pseudo-polynomial time"[1] that can be solved by a variety of tools, as demonstrated in these comments. Even though this simple example can be solved, the general problem (from a set of N integers, find all subsets that add up to a given integer x) is nonetheless NP-complete. The method of computation (Excel, Prolog, constraint programming, Turing machine) does not change this fact. [1] https://news.ycombinator.com/item?id=5780552 https://news.ycombinator.com/item?id=5780552