These kind of problems are more elegantly solved in logic (aka relational) programming languages like Prolog and similar logic programming implementations like

These kind of problems are more elegantly solved in logic (aka relational) programming languages like Prolog and similar logic programming implementations like miniKanren & Clojure's core.logic. Here's the same problem solved using Clojure's core.logic library https://github.com/swannodette/logic-tutorial/blob/master/src/logic_tutorial/tut3.clj https://github.com/swannodette/logic-tutorial/blob/master/sr...