Hack-A-Sat 3 required the top 10 performing teams from qualifiers to submit write-ups of quals challenges in order to collect their quals cash prize.
If you plan on solving Hack-A-Sat 3 qualifiers challenges, this repository contains solutions for some of them. You might want to pass on reading these in that case. Alternatively, if you're stuck, or want to compare your solution with other players', these are probably exactly what you want.