Huh, part 2 done as well!

Instead of using a recursive CTE to implement topological sort, simply counting numbers of pages that need to go before current did the trick.

github.com/ifoukarakis/...

There is a typo, it's actually day 3.

#sql part had an interesting challenge: build all possible sublists of a list of rows by removing a single item. Self-CROSS JOIN did the trick!