Maybe I have the brainworms from too much SQL but that seems pretty fine? It's an idiomatic CTE that more or less directly translates back to the problem statem

Maybe I have the brainworms from too much SQL but that seems pretty fine? It's an idiomatic CTE that more or less directly translates back to the problem statement. (nitpick: I'd exclude already-found rows from the union to do shortest-path in the CTE instead of doing it later)