Next ← {∧´𝕩=0 ? 0 ; (¯1⊸⊑ + 𝕊∘(¯1⊸↓)∘(«-⊢)) 𝕩}
Read ← •BQN {' ':'‿';'-':'¯';𝕩}¨

Part1 ⇐ +´ Next∘Read¨∘•FLines
Part2 ⇐ +´ Next∘⌽∘Read¨∘•FLines