Uiua

Regex my beloved <3

Run with example input here

FindMul ← regex "mul\\((\\d+),(\\d+)\\)"

PartOne ← (
  &rs ∞ &fo "input-3.txt"
  FindMul
  /+≡(×°⊟⋕⊏1_2)
)

IdDont ← ⊗□"don't()"♭

PartTwo ← (
  &rs ∞ &fo "input-3.txt"
  regex "mul\\(\\d+,\\d+\\)|do\\(\\)|don't\\(\\)"
  ⍢(IdDont.
    ↘1⊃↘↙
    ⊗□"do()"♭.
    ⊂↘1↘
  | IdDont.
    ≠⧻,
  )
  ▽♭=0⌕□"do()".
  ≡(×°⊟⋕⊏1_2♭FindMul)♭
  /+
)

&p "Day 3:"
&pf "Part 1: "
&p PartOne
&pf "Part 2: "
&p PartTwo

Uiua

Decided to try and use Uiua for each day this year. At least I’m not the only one to get this idea ^^

Run with example input here

PartOne ← (
  &rs ∞ &fo "input-1.txt"
  ⊜(⊜⋕≠@ .)≠@\n.
  ≡⍆⍉
  ⌵/-
  /+
)

PartTwo ← (
  &rs ∞ &fo "input-1.txt"
  ⊜(⊜⋕≠@ .)≠@\n.
  ⊢⟜⊣⍉
  0
  ⍢(+⊙(:⊙(×⧻⊚◡⌕)↘1⟜⊢)|⋅(≠0⧻))
  ⊙(◌◌) # just cleaning up the stack
)

&p "Day 1:"
&pf "Part 1: "
&p PartOne
&pf "Part 2: "
&p PartTwo

Uiua

Put this one off for a bit and I’ll put off part two for even longer because I don’t want to deal with any pyramid-shapes of boxes at the moment.
The code for part one feels too long but it works and runs <2s so I’m happy with it for now ^^

Run with example input here

$ ##########
$ #..O..O.O#
$ #......O.#
$ #.OO..O.O#
$ #..O@..O.#
$ #O#..O...#
$ #O..O..O.#
$ #.OO.O.OO#
$ #....O...#
$ ##########
$ 
$ <vv>^<v^>v>^vv^v>v<>v^v<v<^vv<<<^><
$ <><>>v<vvv<>^v^>^<<<><<v<<<v^vv^v>^
$ vvv<<^>^v^^><<>>><>^<<><^vv^^<>vvv<
$ >><^^v>^>vv<>v<<<<v<^v>^<^^>>>^<v<v
$ ><>vv>v^v^<>><>>>><^^>vv>v<^^^>>v^v
$ ^<^^>v^^>v^<^v>v<>>v^v^<v>v^^<^^vv<
$ <<v<^>>^^^^>>>v^<>vvv^><v<<<>^^^vv^
$ <vvv>^>v<^^^^v<>^>vvvv><>>v^<<^^^^^
$ ^><^><>>><>^^<<^^v>>><^<v>^<vv>>v>>
$ >^v><>^v><<<<v>>v<v<v>vvv>^<><<>^><
$ ^>><>^v<><^vvv<^^<><v<<<<<><^v<<<><
$ <<^^<v<^^^><^>>^<v^><<<^>>^v<v^v<v^
$ >^>>^v>vv>^<<^v<>><<><<v<<v><>v<^vv
$ <<<>^^v^>^^>>><<^v>>v^v><^^>>^<>vv^
$ <><^^>^^^<><vvvvv^v<v<<>^v<v>v<<^><
$ <><<><<<^^<<<^<<>><<><^^^>^^<>^>v<>
$ ^^>vv<^v^v<vv>^<><v<^v>^^^>>>^^vvv^
$ >vvv<>>>^<^>>>>>^<<^v>^vvv<>^<><<v>
$ v^^>>><<^^<>>^v^<v^vv<>v^<<>^<^v^v>
$ <^<<<><<^<v><v<>vv>>v><v^<vv<>v^<<^

Pos ← :°⊟♭⊚⊸⌕@@
Move ← (
  ⊸⊗@.
  ⍣(+₁⍤.◡(≠⊙⧻)
    ⍜↙⍣(⬚@.↻₋₁⍤.=⊃(⧻|⊗@#).)∘
  )⋅∘
)

PartOne ← (
  # &rs ∞ &fo "input-15.txt"
  ⊜□¬⦷"\n\n".
  ∩°□°⊟
  : ⊙(▽≠@\n.) ⊜∘≠@\n.
  ↘₄⊛⊂"^>v<"
  ⍢(⊃↘₁⊢
    ⊙(⟜(⨬(⍉|∘)◿₂)
      ⟜(⨬(⍜(↘⊙⊡)Move Pos
        | ⍜(⇌↙⊙⊡)Move +₁Pos
        )=₀◿₃)
      ⨬(⍉|∘)◿₂
    )
  | ≠0⧻)
  ◌
  /+≡/+×[100_1]⊚⌕@O
)

PartTwo ← (
  ""
)

&p "Day 15:"
&pf "Part 1: "
&p PartOne
&pf "Part 2: "
&p PartTwo

Hell yeah!

┻━┻︵ (°□°)/ ︵ ┻━┻

Damn that’s a lot time saved. I love how unassuming the addition looks for how great an effect it has

Welp, got frustrated again with part one because there kept being something wrong with my totally-not-ugly loop and so came here again. I did have to change IsInt (and thus also Cost to account for different handling) for part two though because I kept getting wrong results for my input.
I’m guessing it’s because uiua didn’t see the difference between rounded and non-rounded number anymore.

Here’s the updated, slightly messier version of the two functions that worked out for me in the end :D

IsInt ← ≍°⊟⍉⍜(⊙(⍉≡↙₂))(/+×)⊙⍉⁅
Cost  ← /+×3_1×⟜IsInt⊸AB

_{Could have been done better but I’m lacking the patience for that now}

Nice :D
How’s the speed now?

Uiua

This one was nice. The second part seemed quite daunting at first but wasn’t actually that hard in the end.

Run with example input here

Row    ← ⌕ "XMAS"
RevRow ← ⌕"SAMX"
Sum    ← /+/+
Count  ← +∩Sum⊃Row RevRow

PartOne ← (
  &rs ∞ &fo "input-4.txt"
  ⊜∘≠@\n.
  ⊙+⟜∩Count⟜⍉ # horizontal and vertical search
  ⟜(/+⧈(Count⍉≡⬚@ ↻⇡⧻.)4)
  /+⧈(Count⍉≡⬚@ ↻¯⇡⧻.)4
  ++
)

Mask ← °⊚×2⇡5
# Create variations of X-MAS
Vars ← (
  ["M S"
   " A "
   "M S"]
  ≡♭[∩⟜⍉]≡⇌.
  Mask
  ⊏0⊞▽¤
)

PartTwo ← (
  &rs ∞ &fo "input-4.txt"
  ⊜∘≠@\n.
  ⧈(/+♭⊞≍⊙¤Vars▽Mask♭)3_3
  Sum
)

&p "Day 4:"
&pf "Part 1: "
&p PartOne
&pf "Part 2: "
&p PartTwo

I found multidimensional markers for partition to work really well for finding the fields: Areas ← ⊜□:⇡△.+1⍜♭⊛ It just groups the other array’s contents according to adjacent markers, horizontally and vertically. Took me quite a bit to figure out what’s actually happening in the example in the documentation ^^’

Uiua

I spent a while thinking about how to best do a flood fill in Uiua when I saw that ⊜ (partition) works beautifully with multidimensional markers: “Groups are formed from markers that are adjacent along any axis.”, meaning I just had to convert all letters into numbers and I’d get all indices belonging to a field into an array.
For part 2, I cheated a bit by coming here and reading that you only need to count the edges. To my surprise, the second part is actually a bit faster than part 1. Takes less than 0.2 seconds each though :D

Run with example input here

$ RRRRIICCFF
$ RRRRIICCCF
$ VVRRRCCFFF
$ VVRCCCJFFF
$ VVVVCJJCFE
$ VVIVCCJJEE
$ VVIIICJJEE
$ MIIIIIJJEE
$ MIIISIJEEE
$ MMMISSJEEE
.
N     ← +[0_¯1 0_1 ¯1_0 1_0]
Areas ← ⊜□:⇡△.+1⍜♭⊛
Peri  ← -/+≡(/+∊N¤)⟜¤⟜(×4⧻)
Sides ← (
  ⊙(-¤)↯:▽⊙0×°⊟.+2⌵⊸-+1⊃⊣⊢⊸⍜⍉≡⍆
  ⧻⊚⊸∊1_3⧈(/+/+)2_2.⍜⊡=₀+1:
  +⊙(×2/+/+⧈(∊[[1_0 0_1][0_1 1_0]])2_2◌)
)
Cost! ← /+≡◇(×^0⟜⧻)

PartOne ← (
  # &rs ∞ &fo "input-12.txt"
  ⊜∘≠@\n.
  Cost!Peri Areas
)

PartTwo ← (
  # &rs ∞ &fo "input-12.txt"
  ⊜∘≠@\n.
  Cost!Sides Areas
)

&p "Day 12:"
&pf "Part 1: "
&p PartOne
&pf "Part 2: "
&p PartTwo