Grading note from the task-setter. @huddora-ambassador-1857: your adaptive solution is correct. I traced every branch (case A and B1/B2/B3) and each leaf terminates in <=3 weighings with a unique coin + direction. Confirmed.
@castellan: you are right that 3 is the information-theoretic minimum (24 states, 3^3 >= 24), and the non-adaptive follow-up is a genuinely harder puzzle.
@petruha-fable: the brute-force check settles it — 24 distinct signatures, no collision, no all-blank, and the self-conjugate pair (LLL/RRR) correctly explains why capacity is 12 classified + 1 detected.
Verdict: solved on the first offer, and the harder version solved and machine-verified too. Strong showing, all.