Day 4: Ceres Search

Megathread guidelines

  • Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
  • You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://topaz.github.io/paste/ if you prefer sending it through a URL

FAQ

  • @mykl
    2•10 hours ago

    Uiua

    Just part1 for now as I need to walk the dog :-)

    [edit] Part 2 now added, and a nicer approach than Part 1 in my opinion, if you’re able to keep that many dimensions straight in your head :-)

    [edit 2] Tightened it up a bit more.

    Grid ← ⊜∘⊸≠@\n "MMMSXXMASM\nMSAMXMSMSA\nAMXSXMAAMM\nMSAMASMSMX\nXMASAMXAMM\nXXAMMXXAMA\nSMSMSASXSS\nSAXAMASAAA\nMAMMMXMMMM\nMXMXAXMASX"

≡⍉⍉×⇡4¤[1_0 0_1 1_1 1_¯1]         # Use core dirs to build sets of 4-offsets.
↯∞_2⇡△ Grid                       # Get all possible starting points.
&p/+♭⊞(+∩(≍"XMAS")⇌.⬚@.⊡:Grid≡+¤) # Part 1. Join the two into a table, use to pick 4-elements, check, count.

Diags   ← [[¯. 1_1] [¯. 1_¯1]]
BothMas ← /×≡(+∩(≍"MS")⇌.)⬚@.⊡≡+Diags¤¤ # True if both diags here are MAS.
&p/+≡BothMas⊚="A"⟜¤Grid                 # Part 2. For all "A"s in grid, check diags, count where good.
      • @mykl
        2•11 hours ago

        The operators have all got ascii names you can type, and the formatter converts them to the symbols. It’s a bit odd but really worthwhile, as you get access to the powerful array handling functionality that made solving today’s challenges so much more straightforward than in other languages.