Day 4: Scratchcards

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  • 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)
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  • corristo@programming.dev
    3·
    11 months ago

    APL

    I’m using this years’ AoC to learn (Dyalog) APL, so this is probably terrible code. I’m happy to receive pointers for improvement, particularly if there is a way to write the same logic with tacit functions or inner/outer products that I missed.

    input←⊃⎕NGET'inputs/day4.txt'1
num_matches←'Card [ \d]+: ([ 0-9]+) \| ([ 0-9]+)'⎕S{≢↑∩/0~⍨¨{,⎕CSV⍠'Separator' ' '⊢⍵'S'3}¨⍵.(1↓Lengths↑¨Offsets↓¨⊂Block)} input
⎕←+/2*1-⍨0~⍨num_matches ⍝ part 1
⎕←+/{⍺←0 ⋄ ⍺=≢⍵:⍵ ⋄ (⍺+1)∇⍵ + (≢⍵)↑∊((⍺+1)⍴0)(num_matches[⍺]⍴⍵[⍺])((≢⍵)⍴0)}(≢num_matches)⍴1 ⍝ part 2
    • mykl@lemmy.world
      2·
      11 months ago

      I just posted a solution in Uiua, which is also probably equally terrible, but if you squint you can see some similarities in our approaches.

      • corristo@programming.dev
        2·
        11 months ago

        I haven’t heard of Uiua before, but I can read some things :D I like the idea of rotating the vector instead of manually padding it with the required number of leading zeroes!

        • mykl@lemmy.world
          1·
          11 months ago

          I think it’s only a few months old. I’ve enjoyed playing with it because it allows me to use stack manipulation as an alternative to combinators and every symbol has a fixed arity both of which make it feel a lot more accessible to me.

          I was very pleased with myself when I thought of that rotation trick :-)