~ "aoc.ua" ~ Lines Sections Words

Sections &fras "input/day12.txt"

~Present {Id Shape}

ParsePresent ← (
  Lines
  ⋕°$"_:" °⊂
  ⊙(=@# ≡°□)
  Present
)

~Region {W H Req}

ParseRegion ← (
  °$"_x_: _"
  ⊙⊙(Words)
  ∩₃⋕
  Region
)

⊃(≡◇ParsePresent ↘¯1|≡◇ParseRegion Lines°□⊣)

⍤"3x3 bounding box" ≍ ¤[3 3] ◴⊸≡(△Present~Shape)

⊃(⋅∘|∘)

# bool ? Region Presents
Impossible ← (
  ×⊸⊃(Region~W|Region~H)
  ⊙⊓(Region~Req|≡(/+♭ Present~Shape))
  ⊙(/+×)
  >
)

# int ? Width Height
Blocks ← ×∩(⌊÷3)

# bool ? Region
Guaranteed ← (
  Blocks⊸⊃(Region~W|Region~H)
  ⊙(/+ Region~Req)
  ≤
)

⊃(≡⌟Impossible|≡Guaranteed)

⍤"no searching required" ≍ [1] ◴◡+

◌
/+