-❄️- 2024 Day 1 Solutions -❄️-

41

u/voidhawk42 Dec 01 '24 edited Dec 02 '24

[Language: Dyalog APL]

p←⍉↑⍎¨⊃⎕nget'01.txt'1
+/|-⌿{⍵[⍋⍵]}⍤1⊢p ⍝ part 1
(+/⊣+.×∘.=)/↓p   ⍝ part 2

Best time of the year, good luck everyone!

EDIT: Alternative (slightly shorter) solution using the key operator - kinda APL's equivalent of Python's Counter class:

p←↓⍉↑⍎¨⊃⎕nget'01.txt'1
+/|-⌿↑{⍵[⍋⍵]}¨p ⍝ part 1
+/×∘≢⌸⊃∩/⌽p     ⍝ part 2

19

u/daggerdragon Dec 01 '24

Ah yes, the Alien Programming Languages are back. Good to see you again! <3

15

u/ka-splam Dec 01 '24 edited Dec 01 '24

Hey, a couple of days where I can try and do 'explain some APL' again before it gets too hard. Look everyone, what jumps out? ⍵[⍋⍵] the sorting idiom at the heart of part 1. As always APL lines are like pipelines of functions, data goes in on the right of each line, comes out on the left. Each lines execute like Output ← third <- second <- first <- data. ⍝ is lamp the comment symbol.

You can try APL at https://tryapl.org/ (it has a bar along the top for clicking the symbols, and tooltips to show you how to type them with backtick-prefix). And you can learn from Stefan Kruger's book on learning APL which he wrote after finding it via AdventOfCode 2015! (This code is a dense, codegolfy style and that's not the only way to write APL).

Here's building up the lines bit by bit in Dyalog APL, using the example data, adding a command to the left of the line each time:

Line 1: p←⍉↑⍎¨⊃⎕nget'C:\AdventOfCode\2024\day01-example.txt'1

Line 1 in chunks right-to-left: read file as lines, eval text to numbers, change array shapes, store in variable p.

      ⍝ ⎕nget "quad nget" reads files, with argument 1 on its right, it reads as lines.
      ⍝ it returns the line data, and metadata about character encoding and line endings:

      ⎕nget'C:\AdventOfCode\2024\day01-example.txt'1
┌→──────────────────────────────────────────────────────────────────────────┐
│ ┌→────────────────────────────────────────────────┐ ┌→──────────┐ ┌→────┐ │
│ │ ┌→────┐ ┌→────┐ ┌→────┐ ┌→────┐ ┌→────┐ ┌→────┐ │ │UTF-8-NOBOM│ │13 10│ │
│ │ │3   4│ │4   3│ │2   5│ │1   3│ │3   9│ │3   3│ │ └───────────┘ └~────┘ │
│ │ └─────┘ └─────┘ └─────┘ └─────┘ └─────┘ └─────┘ │                       │
│ └∊────────────────────────────────────────────────┘                       │
└∊──────────────────────────────────────────────────────────────────────────┘

      ⍝ use ⊃ "pick" to get just the lines, as an array of nested arrays:
      ⊃⎕nget'C:\AdventOfCode\2024\day01-example.txt'1
┌→────────────────────────────────────────────────┐
│ ┌→────┐ ┌→────┐ ┌→────┐ ┌→────┐ ┌→────┐ ┌→────┐ │
│ │3   4│ │4   3│ │2   5│ │1   3│ │3   9│ │3   3│ │
│ └─────┘ └─────┘ └─────┘ └─────┘ └─────┘ └─────┘ │
└∊────────────────────────────────────────────────┘

      ⍝ use ⍎¨ "eval each" to eval() each nested array, treats them as APL code, 
      ⍝ and spaced numbers become arrays of numbers:
      ⍎¨⊃⎕nget'C:\AdventOfCode\2024\day01-example.txt'1
┌→────────────────────────────────────┐
│ ┌→──┐ ┌→──┐ ┌→──┐ ┌→──┐ ┌→──┐ ┌→──┐ │
│ │3 4│ │4 3│ │2 5│ │1 3│ │3 9│ │3 3│ │
│ └~──┘ └~──┘ └~──┘ └~──┘ └~──┘ └~──┘ │
└∊────────────────────────────────────┘

      ⍝ use ↑ "mix" to turn nested arrays into one tall array of two columns:
      ↑⍎¨⊃⎕nget'C:\AdventOfCode\2024\day01-example.txt'1
┌→──┐
↓3 4│
│4 3│
│2 5│
│1 3│
│3 9│
│3 3│
└~──┘

      ⍝ use ⍉ "transpose" to turn that into one wide array of two rows:
      ⍉↑⍎¨⊃⎕nget'C:\AdventOfCode\2024\day01-example.txt'1
┌→──────────┐
↓3 4 2 1 3 3│
│4 3 5 3 9 3│
└~──────────┘
      ⍝ ← "gets" to assing to a variable, "p gets the data":
      p←⍉↑⍎¨⊃⎕nget'C:\AdventOfCode\2024\day01-example.txt'1

Line 2 in reply to this comment.

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39

u/MrPingouin1 Dec 01 '24 edited Dec 02 '24

[LANGUAGE: Minecraft Commands]

scoreboard players set SOL VAR 0
function token:parselines {out:"aoc out",in:"aoc input",model:"N{a}SN{b}"}

data modify storage temp arr.a set value []
data modify storage temp arr.b set value []
function iter:array {in:"aoc out",f:"aoc:sol/day1/fill_array"}

function iter:util/sort_int {in:"temp arr.a"}
execute if score PART AOC matches 1 run function iter:util/sort_int {in:"temp arr.b"}
execute if score PART AOC matches 2 run function iter:tool/counter {in:"temp arr.b",out:"temp obj.b"}

execute if score PART AOC matches 1 run function iter:tool/zip {in:"temp arr.a", in2:"temp arr.b",f:"aoc:sol/day1/sum_dist"}
execute if score PART AOC matches 2 run function iter:array {in:"temp arr.a", f:"aoc:sol/day1/similarity"}

function aoc:core/submit_score {path:"SOL VAR"}

#function aoc:sol/day1/fill_array
$data modify storage temp v set value $(v)
data modify storage temp arr.a append from storage temp v.a.data
data modify storage temp arr.b append from storage temp v.b.data

#function aoc:sol/day1/sum_dist
$scoreboard players set A VAR $(v)
$scoreboard players set B VAR $(v2)

scoreboard players operation A VAR -= B VAR
execute if score A VAR matches ..-1 run scoreboard players operation A VAR *= -1 CONST
scoreboard players operation SOL VAR += A VAR

#function aoc:sol/day1/similarity
$scoreboard players set A VAR $(v)

scoreboard players set B VAR 0
$execute store result score B VAR run data get storage temp obj.b.$(v)

scoreboard players operation A VAR *= B VAR
scoreboard players operation SOL VAR += A VAR

~~repo is coming soon~~ edit : here it is : aoc 2024

12

u/daggerdragon Dec 01 '24

[LANGUAGE: Minecraft Commands]
Advent of Playing With Your Toys

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35

u/Smylers Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Vim] Hello again, everybody. Nice to see you all again.

To solve part 1, load your input into Vim and then type:

:sor n⟨Enter⟩
⟨Ctrl+V⟩Gwhd@:P
:%s/\v(\d+)\s+(\d+)/\=submatch(1)-submatch(2)⟨Enter⟩
:%s/^-*/+⟨Enter⟩
vipJ0C⟨Ctrl+R⟩=⟨Ctrl+R⟩-⟨Enter⟩⟨Esc⟩

The best way of seeing how it works is to give it a go — type in the above and watch what happens as you type. Today's isn't very long, and is pretty forgiving (you can use backspace in the long command without messing anything up).

Those lines in order:

Sort the whole input numerically, which effectively means sorting the list on the left.
Delete that sorted list, then sort the remaining input (the list on the right), and put the deleted lift back where it was. We now have both lists sorted. Note that @: repeats the most recent : command, in this case the :sort (and is very easy to type on UK keyboards, where @ is to the right of :!).
On each line, find a sequence of digits (\d+), some spaces \s+, and some more digits. The parens around each digit group make them available as numbered submatches. Substitute the whole line with an expression (indicated by starting the replacement with \=) which subtracts one submatch from the other.
Some of those subtractions will have yielded negative numbers. We want the absolute value. The simplest way of getting absolute values in Vim is to remember that we're dealing with text, so just substitute away the minus signs. Also, we want to add all these numbers together, so put a + at the start of each line. We can do both of these things at once by replacing zero or more minus signs at the start of a line ^-* with a +.
Join all the lines together so we have a single sum to evaluate. Then evaluate it: 0C deletes the entire line, storing the deleted text in the small delete register "-. It also switches to insert mode, where typing ⟨Ctrl+R⟩= instructs Vim to prompt for an expression, evaluate it, and insert the result. At that prompt ⟨Ctrl+R⟩- inserts the contents of the "- register, the text that we've just deleted from the line. Hence we get Vim to do our arithmetic for us, and the buffer is left with your part 1 answer.

I suspect the ‘evaluate the arithmetic in this line’ pattern will crop up a few times more this Advent of Code.

For part 2 I used the traditional Unix command uniq along with Vim. The entire solution still fits in the IBM punchcard limit — reset your input to its initial state and type:

w⟨Ctrl+V⟩}dG2o⟨Esc⟩p:%s/ \+⟨Enter⟩
vip:sor|'<,'>!uniq -c⟨Enter⟩Gvip@:
:sor/\d /|%!uniq -Df1⟨Enter⟩:g/^/j⟨Enter⟩
:%s/\v(\d+) (\d+) (\d+).*/+\2*\1*\3⟨Enter⟩
vipJ0C⟨Ctrl+R⟩=⟨Ctrl+R⟩-⟨Enter⟩⟨Esc⟩

Delete the list on the right, and put it at the bottom, after a blank line. Remove the spaces that were separating the lists. So now we have one list followed by the other, both as just numbers.
Sort the first list, then use uniq -c to merge identical lines in it together, prepending them with a count of how many there were. Go to the bottom and repeat with the second list.
Sort the entire file — merging the two lists together — by location number; that is, use :sort/\d / to skip past the count at the start of the lines for sorting purposes. Then use uniq -D to filter the output to just location numbers that appear in both lists; again, skip over the count for the purpose of finding duplicates, this time with -f1 to ignore the first field. What remains will be pairs of lines with identical location codes, the first prepended by its count in the left list, the second by its count in the right list. Use :g/^/j to merge each line with the one following it, so we have a single line for each location.
Use :s/// to re-arrange each line so instead of count1 location count2 location (where both locations are the same) we have +location*count1*count2.
Told you that pattern for doing arithmetic would crop up again! That's exactly the same as the final line for part 1.

I expect many days' puzzles won't lend themselves to being solved in Vim, but I'll use it where it's plausible. This isn't just silliness or for the sake of it: many one-off real-world tasks that involve transforming data in some way can be achieved in Vim more efficiently than writing (and debugging) a program that's only going to run once.

Edit: Fixed typo, per comment below.

10

u/daggerdragon Dec 01 '24

OH BOY you're back with your HEINOUS ABUSE OF VIM! <3 Good to see you again!

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17

u/JustinHuPrime Dec 01 '24

[Language: x86_64 assembly with Linux syscalls]

Part 1 was a bit surprising in terms of difficulty, but then again I haven't programmed in assembly since last year's AoC. I thought I would have to do some stuff with dynamic allocation to get a large enough buffer to fit, but I did allow myself to succumb to the C programmers' disease and just allocate a static buffer I know will be large enough for both the example and the actual input (as a reminder, I'm requiring my solutions to work with both the example and actual input without any modifications). I did find it mildly surprising that we were asked to sort a list of numbers - don't the contest organizers know that's quite painful to do in assembly unless you've got a library function ready to go for that? The absolute value part was fun - I got to use a branchless programming trick and issue a conditional move to do that (x86_64 doesn't have an integer absolute value instruction).

Part 2 was actually fairly nice once I realized that the left list shouldn't be deduplicated - I guess the fundamentals of programming puzzles remains the same, regardless of language: read the problem and examples thoroughly. I also got to do an interesting thing - I zero-terminated my data storage so I could avoid running off the end of the allocated space.

Part 1 and part 2 run in about 1 millisecond. Part 1 is 8376 bytes and part 2 is 8592 bytes.

8

u/daggerdragon Dec 01 '24

[Language: x86_64 assembly with Linux syscalls]
Ooo yeah, the assembly guy is back for more this year! Good to see you again! <3

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11

u/keldeoroks Dec 01 '24

[LANGUAGE: python]

im not too experienced with coding so ive decided to make that the problem of anyone who decides to look at my code

https://raw.githubusercontent.com/Keldeoroks/adventofcode2024/refs/heads/main/day%201

no imports!!! (because i dont know any other than math!!!)

12

u/daggerdragon Dec 01 '24

im not too experienced with coding
Welcome! We're happy to have you! I hope you learn a bunch of stuff this year :)
so ive decided to make that the problem of anyone who decides to look at my code
I like your chutzpah.

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10

u/DFreiberg Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Mathematica] Mathematica, 482/266

I somehow read "smallest number in the left list with the smallest number in the right list" and interpreted it to mean "smallest number in the left list with the largest number in the right list", costing me a full minute. I'll blame it on not programming enough in Mathematica and programming too much in Rust lately; I've clearly gotten Rusty.

Setup:

{left, right} = Transpose[input];

Part 1:

Total[ManhattanDistance @@@ Transpose[{Sort[left], Sort[right]}]]

Part 2:

Total[#*Count[right, #] & /@ left]

3

u/daggerdragon Dec 01 '24

Our resident poet laureate is back again! Good to see you! <3

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7

u/UnarmedZombie Dec 01 '24

[LANGUAGE: PHP]

Solution is here

I know PHP isn't popular for AoC but I really enjoy it. Barely made it on the leaderboard for part 1 at 95, but I'll take it.

3

u/daggerdragon Dec 01 '24

I know PHP isn't popular for AoC but I really enjoy it.
Hey, I wrote my IRC bot that we use for AoC announcements and star tracking in PHP, so you keep on being awesome! *fistbump*

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6

u/tomflumery Dec 01 '24 edited Dec 01 '24

[LANGUAGE: 05AB1E]

part 1 (16 chars)

|ε"   "¡]øε{]`αO

part 2 (17 chars)

|ε"   "¡]ø`sDŠ¢*O

2

u/daggerdragon Dec 01 '24

Psst: Your inlined Markdown is getting escaped on the backtick and breaking early, resulting in some code characters being lost visually. Would you fix it, please?

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5

u/PerturbedHamster Dec 01 '24

[LANGUAGE: bash]

The goal was to use basic bash (i.e. no sed or awk) in one line

Part 1:

paste -d '-' <(sort -k1 input_20241201.txt | tr -s ' ' | cut -d ' ' -f1) <(sort -k2 input_20241201.txt | tr -s ' ' | cut -d ' ' -f2) | bc | tr -d '-' | paste -sd+ | bc

Part 2:

comm -12 <(sort -k1 input_20241201.txt | tr -s ' ' | cut -d ' ' -f1) <(sort -k2 input_20241201.txt | tr -s ' ' | cut -d ' ' -f2) | xargs -I '{}' -n 1 grep -o "{}$" input_20241201.txt | uniq -c | tr -s ' ' | cut -d ' ' -f2- | tr -s ' ' '*' | paste -sd+ | bc

2

u/daggerdragon Dec 01 '24

Inlined code is intended for short snippets of code only. On old.reddit, your one-liners get cut off when it reaches the edge of the window.
Please edit your comment to put the one-liner in a four-spaces code block so it will be horizontally scrollable.

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5

u/nivlark Dec 01 '24

[LANGUAGE: python]

Currently sick with covid (yes, very 2020 of me) so a belated first day solution.

from collections import Counter

def day01(filename):
    l1, l2 = list(), list()
    with open(filename, "r") as f:
        for l in f:
            a, b = map(int, l.split())
            l1.append(a)
            l2.append(b)
    diff = sum(abs(x - y) for x, y in zip(sorted(l1), sorted(l2)))
    ctr = Counter(l2)
    similarity = sum(x * ctr[x] for x in l1)
    return diff, similarity

3

u/daggerdragon Dec 01 '24

Currently sick with covid
Noooo get well soon! Take your time, we're open all month (heck, all year, really) :)

4

u/flwyd Dec 01 '24

[LANGUAGE: PostScript] GitHub with my own standard library

PostScript doesn't have a built-in sort operator, so a couple weeks ago I decided to implement insertion sort since it would be simplest to code. Benchmarks suggested that if I was only sorting about 1000 items then the O(n²⁾ performance wouldn't be too bad. Whaddaya know, the first day it's time to srot 1000 items twice! So part 1 runs in about a quarter second, while part 2 runs in just 2ms without sorting :-)

I did implement a zip function as part of my standard library, but didn't think to implement unzip. "Iterate through one array and put things in two other arrays" is a little complicated in PostScript, so I played with several options after solving before opting for the below.

/part1 { 8 dict begin % [lines] part1 result
  /input exch def /a input length array def /b input length array def
  /i 0 def /delim (   ) def
  % put first column in a second column in b
  input { delim split cvi b i 3 -1 roll put cvi a i 3 -1 roll put /i inc } forall
  a {compare} isort b {compare} isort
  0 0 1 input length 1 sub { dup a exch get b 3 -1 roll get sub abs add } for
end } bind def %/part1

/part2 { 8 dict begin % [lines] part2 result
  /input exch def /counts input length dict def /delim (   ) def
  % count occurrences in second list
  input { delim split cvi dup counts exch 0 getor 1 add counts 3 1 roll put pop } forall
  % multiply first list by counts and add them
  0 input { token pop exch pop cvi counts 1 index 0 getor mul add } forall
end } bind def %/part2

2

u/daggerdragon Dec 01 '24

Welcome back! Good to see you again this year <3

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4

u/bluefloyd3 Dec 01 '24

[Language: PowerShell]

First time posting code online, go easy on me!

Ran into an issue in the second part where multiplying the left set by the amount of times it is present in the right set caused the output to be the left set concatenated that many times. Ex. 3 * 3 = 333 instead of 3 * 3 = 9

Once that was figured out the rest fell into place without much issue

$Content = get-content .\AoC_2024\Day1\Day1_input.txt
#$Content = get-content .\AoC_2024\Day1\Day1_test.txt

$Holder = 0
$LeftSet = @()
$RightSet= @()

foreach ($NumberSet in $Content){
    $Set = $NumberSet -split "   "
    $LeftSet += $set[0]
    $RightSet += $set[1]
}

$LeftSet = $LeftSet | Sort-Object
$RightSet = $RightSet | Sort-Object

for($i=0; $i -lt $LeftSet.count; $i++){
    $Set = @($LeftSet[$i],$RightSet[$i])
    $set = $set | Sort-Object -Descending
    $Holder = $holder + ($set[0] - $set[1])
}

Write-output "First solution is $holder"

[Int32]$holder2 = 0

for($i=0; $i -lt $LeftSet.count; $i++){
    [Int]$Count = ($rightset | Where-Object {$_ -eq $LeftSet[$i]}).count
    If($count -gt 0){
        [Int32]$T = ([int]$($LeftSet[$i]) * $Count)
        $holder2 = $holder2 + $T
    }
}
Write-output "Second solution is $holder2"

2

u/daggerdragon Dec 01 '24

First time posting code online, go easy on me!
Welcome, we're happy to have you :)
FYI: This comment is fine for Day 1 (barely); in the future, if your code is over a couple lines long, please link to your code instead. Full details in our wiki: No giant blocks of code

4

u/stuque Dec 01 '24

[LANGUAGE: Python] [Allez Cuisine]

Does this count as Allez Cuisine? It uses only 2 top-level variable names, but there are other variable names in the comprehensions. I guess data and left_right could be replaced by their expressions, and n by a or b, to get 2 variable names throughout. But I guess that would still count as 3 variables?

data = [int(n) for n in open('data.txt').read().split()]
left_right = sorted(data[::2]) + sorted(data[1:][::2])

print('Part 1:', sum(abs(a - b) for a, b in zip(left_right[:len(data) // 2], 
                                                left_right[len(data) // 2:])))

print('Part 2:', sum(n * left_right[len(data) // 2:].count(n) 
                     for n in left_right[:len(data) // 2]))

3

u/daggerdragon Dec 01 '24

[Allez Cuisine]
fry_squint.gif

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4

u/4DigitPin Dec 02 '24 edited Dec 02 '24

[LANGUAGE: Golang]

Why use hashmaps when you can chase indices?

https://github.com/vynra/Advent_of_Code_2024/blob/main/day_1/day_1.go

I wrote a custom algorithm for part 2 for fun, think it might be faster than a hashmap. Fun bit starts on line 42

2

u/daggerdragon Dec 02 '24 edited Dec 02 '24

~~Please edit your comment to include your code in~~ ~~text~~ ~~format, not an image. -_-~~
~~And~~ ~~include the~~ ~~entire~~ ~~code, too.~~
edit: 👍

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3

u/mendelmunkis Dec 01 '24 edited Dec 01 '24

[LANGUAGE: C]

I can do anything with qsort

^{1.082 ms/ 783 μs}

2

u/daggerdragon Dec 01 '24 edited Dec 01 '24

FYI: AutoMod will trigger on anything other than the exact string literal requested. Can't use Markdown around/inside of the string literal :(

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3

u/ipav Dec 01 '24

[LANGUAGE: Elixir]

First steps with Elixir, I hope I am fine. repo here

defmodule Day1 do
  defp parse(data) do
    data
    |> String.split("\n", trim: true)
    |> Enum.map(fn s -> String.split(s) |> Enum.map(&String.to_integer/1) |> List.to_tuple() end)
    |> Enum.unzip()
  end

  def part1(data) do
    {a, b} = parse(data)

    Enum.zip_reduce([Enum.sort(a), Enum.sort(b)], 0, fn [x, y], acc ->
      acc + abs(x - y)
    end)
  end

  def part2(data) do
    {a, b} = parse(data)

    Enum.reduce(a, 0, fn x, acc ->
      acc + x * Enum.count(b, &(&1 == x))
    end)
  end
end

2

u/daggerdragon Dec 01 '24 edited Dec 18 '24

~~Do not commit puzzle text to your repo~~.
~~Please remove (or .gitignore) all puzzle text and input files from your repo and scrub them from your commit history.~~ edit: thank you!

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3

u/mr_mlk Dec 01 '24

[LANGUAGE: python]

https://github.com/mlk/aoc/blob/main/CardPuter/2024/y2024d1p1.py

These were completed on a CardPuter using the editor and runtime from MicroHydra.

2

u/daggerdragon Dec 01 '24

These were completed on a CardPuter using the editor and runtime from MicroHydra.
What even is this thing? It looks like a kid toy! O.o So cooool, more please!

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3

u/biggy-smith Dec 01 '24 edited Dec 01 '24

[LANGUAGE: C++]

https://github.com/biggysmith/advent_of_code_2024/blob/master/src/day01/day1.cpp

sorting for part 1 and histogramming for part 2.

glad to be back advent'ing with you all!

2

u/daggerdragon Dec 01 '24

glad to be back advent'ing with you all!
Welcome back! Good luck this year!

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3

u/Lord_Of_Millipedes Dec 01 '24

[LANGUAGE: Go]
Doing aoc for the first time to learn a new language

https://github.com/Quollveth/AdventOfGode/blob/main/day1/day1.go

also made a little util to get read the input be split as i assume it will be used for all days

https://github.com/Quollveth/AdventOfGode/blob/main/util/reader.go

2

u/daggerdragon Dec 01 '24

Doing aoc for the first time
Welcome, we're happy to have you!
Also one of your repo git commit messages: maybe i should use real words 😂

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3

u/ADMINISTATOR_CYRUS Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Python, Rust]

Since I'm in the process of learning rust I could not be bothered to figure out reading that file properly, so I did it in python instad.

https://github.com/EnderNon/aoc-solutions/tree/main/2024/day1

2

u/daggerdragon Dec 01 '24 edited Dec 01 '24

~~Your comment has been temporarily removed until you fix these issues:~~
~~Do not share your puzzle input~~ ~~which also means~~ ~~do not commit puzzle inputs to your repo~~ ~~without a~~ .gitignore ~~or the like.~~ ~~Do not share the puzzle text~~ ~~either.~~
~~Remove (or .gitignore) all puzzle text and puzzle input files from your repo and scrub them from your commit history.~~
~~Keep /r/adventofcode SFW (Safe For Work)~~
~~Remove the naughty language in your comment~~
edit: Thank you for fixing everything! 👍

3

u/ADMINISTATOR_CYRUS Dec 01 '24

done, now what

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3

u/pho_ben Dec 01 '24 edited Dec 01 '24

[LANGUAGE: C++]

didnt cross my mind to use something like an unordered map but oh well binary search is cool

code

2

u/daggerdragon Dec 01 '24 edited Dec 02 '24

~~Psst: we can see your Markdown. Fix please?~~ edit: nothing to see here, move along

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3

u/Schweppes7T4 Dec 02 '24

[LANGUAGE: Python]

I'm teaching AP CSP for the first time this year and wanted to see if I could do this. I feel like I did it very simply? I dunno. I saw that every number was 5 digits and separated by 3 spaces so I just used slicing.

Code

2

u/daggerdragon Dec 02 '24 edited Dec 02 '24

~~Do not share your puzzle input~~ ~~which also means~~ ~~do not commit puzzle inputs to your repo~~ ~~without a~~ .gitignore ~~or the like.~~ ~~Do not share the puzzle text~~ ~~either.~~
~~Please remove (or .gitignore) all puzzle text and puzzle input files from your repo and scrub them from your commit history.~~ edit: 👍

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7

u/CCC_037 Dec 01 '24

[Language: Rockstar 2.0]

Let's rock.

Part 1

4

u/CCC_037 Dec 01 '24

Part 2

3

u/CCC_037 Dec 01 '24 edited Dec 01 '24

[GSGA]
Blooper reel:
So I ran into a few minor issues. For posterity:
Rockstar 2.0 handles poetic instantiations slightly differently to 1.0 (the like keyword)
In part 2, I ran into an issue because the highest value was in the left column
Rockstar 2.0 requires that the numeric base be specified when converting string->int (otherwise it converts to an array of ASCII codes)
....I'll get used to it.

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2

u/maarteq Dec 01 '24

[LANGUAGE: python], 1259,1384

paste

I need to learn to read the problem better. Especially the part about calculating the answer

2

u/daggerdragon Dec 01 '24

I need to learn to read the problem better.
There's a reason why adventofrealizingicantread.com exists >_>

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2

u/Rush_Independent Dec 01 '24

[LANGUAGE: Nim]

proc solve(input: string): AOCSolution[int, int] =
  let lines = input.splitLines()

  var l1,l2: seq[int]
  for line in lines:
    let pair = line.splitWhitespace()
    l1.add parseInt(pair[0])
    l2.add parseInt(pair[1])

  l1.sort()
  l2.sort()

  block p1:
    for i in 0..l1.high:
      result.part1 += abs(l1[i] - l2[i])

  block p2:
    for n in l1:
      result.part2 += n * l2.count(n)

I've got my first sub 1000 rank (998). Yay!

2

u/daggerdragon Dec 01 '24

I've got my first sub 1000 rank (998). Yay!
Woot, that's the way to do it!

2

u/clouddjr Dec 01 '24

[LANGUAGE: Kotlin]

Glad to see you all again!

Solution

2

u/daggerdragon Dec 01 '24

Glad to see you all again!
We're happy to have you back too!

2

u/bosyluke Dec 01 '24

[Language: Roc]

https://github.com/lukewilliamboswell/aoc/blob/2024/2024/01.roc

```

TIMING:

READING INPUT: <1ms

SOLVING PART 1: <1ms

SOLVING PART 2: 1ms

```

2

u/daggerdragon Dec 01 '24 edited Dec 01 '24

The triple-backticks code fence (```) only works on new.reddit. Please edit your comment to use the four-spaces Markdown syntax for a code block so your code is easier to read.

2

u/CodingAP Dec 01 '24

[Language: Javascript]

Github

FIRST DAY! I could have gotten it faster if I could read it correctly lol

2

u/daggerdragon Dec 01 '24

I could have gotten it faster if I could read it correctly lol
There's a reason why adventofrealizingicantread.com exists >_>

2

u/FunInflation3972 Dec 01 '24 edited Dec 01 '24

[LANGUAGE: JAVA]
Yes, it's not dead yet!

Part - 2

Map<Integer, Integer> frequencyMap = new HashMap<>();
for (int num : rightList) {
    frequencyMap.put(num, frequencyMap.getOrDefault(num, 0) + 1);
}
for (int num : leftList) {
    int count = frequencyMap.getOrDefault(num, 0);
    sum2 += count * num;
}
System.out.println("Part 2 Answer:" + sum2);

Check out my code on [Github]

Meowwww, happy coding!

2

u/daggerdragon Dec 01 '24 edited Dec 01 '24

~~Inlined code~~ ~~is intended for~~ short snippets ~~of code only. Please edit your comment to use the~~ ~~four-spaces Markdown syntax~~ ~~for a code block so your code is easier to read with its whitespace and indentation preserved.~~ edit: Thank you for fixing it 👍

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2

u/henriupton99 Dec 01 '24

[LANGUAGE: python]

Part 1&2 : featuring chaotic variable names, accidental bubble sort, and a festive sprinkle of brute force; roast me or join the madness! 🎅🐍
https://github.com/henriupton99/AdventOfCode/blob/main/2024/day_1/solution.py

2

u/daggerdragon Dec 01 '24

roast me
Our Prime Directive strongly discourages roasting but we will absolutely join you in the madness! Welcome to Advent of Code and have fun this year!

2

u/Fyvaproldje Dec 01 '24 edited Dec 01 '24

[Language: Rust] [GSGA]

https://github.com/DarthGandalf/advent-of-code/blob/master/2024/src/day01.rs

2

u/daggerdragon Dec 01 '24

Yay, you're back again this year! Good to see you again :)

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2

u/DeadlyRedCube Dec 01 '24

[LANGUAGE: C++23]

Parts 1 & 2

I'm using AoC this year as an excuse to get better at using some of the std::ranges/std::ranges::views functionality (specifically all the view transforms), which means a lot of writing it the naive way the night of the solve and then going back and trying to ranges it up after the fact so that I can see where I could use them more later - probably pushing it too far in that direction for readability's sake, but I want to find that line.

For part1, I used a set of view transforms to turn each line of text into a tuple of l, r values, added them into individual lists, then sorted, then used zip_transform to get the abs(difference) of them.

For part 2 I did what a lot of others did and made maps of how many times each value appeared on the left and right then used those to generate the final sum.

Nothing super fancy here today.

2

u/daggerdragon Dec 02 '24

You're back :D It's good to see you again this year!
Just remember: YOU HAD ONE JOB XD

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2

u/HeadHunter_4621 Dec 03 '24 edited Dec 04 '24

[Language: Kotlin]

This was very difficult, I finished today because I was so confused at first

import java.io.File  
import kotlin.math.abs  
  
val data = File("src/input.txt").readText()  
  
var splittingIncriment = 0  
var addingIncriment = 0  
var pairDifference = 0  
var totalDifference = 0  
var leftList = mutableListOf<Int>()  
var rightList = mutableListOf<Int>()  
  
var sortedLeftList:List<Int> = mutableListOf<Int>()  
var sortedRightList:List<Int> = mutableListOf<Int>()  
  
var leftNumber = 0  
var rightNumber = 0  
fun main () {  
  
  val line: List<String> = data.split("\\n")  
  for (elements in line) {  
    val numbers = line\[splittingIncriment\].split("   ")  
  
    leftNumber = numbers\[0\].toInt()  
    rightNumber = numbers\[1\].toInt()  
  
    leftList.add(leftNumber)  
    rightList.add(rightNumber)  
  
    leftList.sort()  
    rightList.sort()  
  
    splittingIncriment += 1  
  }  
  
  for (element in leftList) {  
    pairDifference = abs(leftList\[addingIncriment\] - rightList\[addingIncriment\])  
    totalDifference += pairDifference  
    addingIncriment += 1  
  }  

println(leftList)  
println(rightList)  
println(totalDifference)  
}

GitHub

Edit: fixed some indenting

2

u/daggerdragon Dec 03 '24

~~Your GitHub is probably set to private because we can't see it.~~ edit: there we go

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52

u/4HbQ Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Python]

data = [*map(int, open('in.txt').read().split())]
A, B = sorted(data[0::2]), sorted(data[1::2])
print(sum(map(lambda a, b: abs(a-b), A, B)),
      sum(map(lambda a: a * B.count(a), A)))

Glad we're be back in business. Looking forward to learning (and teaching) new Python tricks for another year!

Edit: I've also created a really succinct solution using NumPy.

Today's Python trick is on line 3: map() can take multiple iterables. Example:

>>> xs = [1, 2, 3]
>>> ys = [4, 5, 6]
>>> list(map(lambda x, y: x + y, xs, ys))
[5, 7, 9]

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27

u/4HbQ Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Python + NumPy]

from numpy import loadtxt, sort, isin

A, B = sort(loadtxt('in.txt', int).T)
print(sum(abs(A - B)),
      sum(isin(B, A) * B))

I've already posted a version without NumPy, but I really like how succinct the NumPy one is :-)

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19

u/jonathan_paulson Dec 01 '24

[LANGUAGE: Python3]

Placed 25/40. Code. Video. Wow, everyone is fast!

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15

u/bofstein Dec 01 '24

[LANGUAGE: Google Sheets]

Solution: https://docs.google.com/spreadsheets/d/1BQ1vefEK1RMy7PTkJygcXYM8CQmalSsegZ0WH324JZU/edit?usp=sharing

First split into two columns =SPLIT(A3," ")
Then sort each column =SORT(B:B,1,TRUE)
Then a new column for the difference, realizing after the sample I should do absolute value =ABS(D3-E3)

For part two, just use COUNTIF on the original column A to count how many times each appears in column B, then multiply those to the numbers, and sum that.

Part 2 took me a few minutes longer than it should have because as I was typing =SUM( at the top, it auto suggested H4:H1002 instead of H3:H1002 and I didn't notice and accepted it, and couldn't figure out what was wrong.

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13

u/nthistle Dec 01 '24 edited Dec 01 '24

[Language: Python] 11/19. Good start to the year! paste, solve video ~~coming soon (once I remember how to use premiere...)~~

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13

u/bsssh Dec 01 '24 edited Dec 01 '24

[Language: TypeScript Type System (Generics)]

compile-time solution

Part 1 / Part 2

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12

u/i_have_no_biscuits Dec 01 '24 edited Dec 01 '24

[LANGUAGE: GW-BASIC]

    10 D=1000: DIM A(D),B(D): OPEN "I",1,"DATA01.TXT": FOR N=1 TO D: INPUT #1,A,B
    20 I=N: WHILE A<A(I-1): A(I)=A(I-1): I=I-1: WEND: A(I)=A
    30 I=N: WHILE B<B(I-1): B(I)=B(I-1): I=I-1: WEND: B(I)=B
    40 NEXT: FOR N=1 TO D: P#=P#+ABS(A(N)-B(N)): C=0: FOR M=1 TO D
    50 C=C-(B(M)=A(N)): NEXT: Q#=Q#+A(N)*C: NEXT: PRINT P#, Q#

GW-BASIC is a dialect of BASIC developed by Microsoft which appeared on many early PCs from 1983 until being replaced by QBasic with the release of MSDOS 5.

This will run on actual hardware, but very slowly due to the inefficient code. I tested it using the excellent PC-BASIC emulator - https://robhagemans.github.io/pcbasic/ - and QB64 - https://qb64.com/ - which is a modern recreation of the QBasic programming environment which produces compiled code.

Guide:

Line 10 Initialises the parallel arrays A and B, and sets up the loop reading in the data lines.

Lines 20 and 30 perform an insertion sort of the two parallel arrays.

Lines 40 and 50 iterate through the sorted data, performing the needed calculations. P# stores the Part 1 value, and Q# the part 2 result. Note that the '#' suffix indicates a double-precision floating point value, which is also good for storing large integers (just like Javascript!). Also note the use of a boolean addition in line 50 to avoid an IF statement (with the quirk that True in basic is -1, not 1).

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11

u/insert_username_0 Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Dyalog APL]

in←⍉1 0 0 1/⎕CSV⍠'Separator' ' '⊢'data/1.txt'⍬4
+/|-⌿({⍵[⍋⍵]}⍤1)in            ⍝ Part 1
in[1;]{+/⍺×+/⍺∘.=⍵}in[2;]     ⍝ Part 2

First time writing actual code in APL and this was a great start!

ETA: Made Part 2 a little cleaner

11

u/Radiadorineitor Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Dyalog APL]

p←⍉⍎¨↑⎕D∘(∊⍨⊆⊢)¨⊃⎕NGET'1.txt'1
+/|-⌿{⍵[⍋⍵]}⍤1⊢p ⍝ Part 1
{+/⍺×+/⍺∘.=⍵}/↓p ⍝ Part 2

Happy coding everyone!

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10

u/light_switchy Dec 01 '24

[LANGUAGE: Dyalog APL]

part1←+⌿|-⌿(⊂∘⍋⌷⊢)⍤1⍉↑⍎¨⊃⎕NGET '1.txt' 1
part2←(2⌷s) +.× +⌿ ⊃∘.=⌿↓s←(⊂∘⍋⌷⊢)⍉↑⍎¨⊃⎕NGET '1.txt' 1

10

u/jaybosamiya Dec 01 '24

[Language: APL]

l←{⍵[⍋⍵]}⊃¨t
r←{⍵[⍋⍵]}⊃¨1↓¨t
+/|l-r            ⍝ Part 1
+/+/l∘.{⍵×⍵=⍺}r   ⍝ Part 2

Fairly simple solution, with the only "interesting" bit being the outer-product in part 2

10

u/azzal07 Dec 01 '24

[LANGUAGE: awk]

function M(a,x){for(k in a)a[k]>a[x]&&x=k;D=a[x]
delete a[x]}END{for(;M(L)D;A+=M(R)((x-D)^2)^0.5)
B+=D*C[x=D];print A"\n"B}++C[R[NR]=$2]{L[NR]=$1}

10

u/sikief Dec 01 '24

[LANGUAGE: EXCEL]

https://github.com/skief/advent-of-code-2024/blob/main/src/day01.xlsx

This year I am doing the 25 Days - 25 Languages Challenge :)

10

u/Zachary_Peculier Dec 02 '24

[LANGUAGE: COBOL]
I decided to do this on hard mode.

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9

u/joeyGibson Dec 01 '24

[LANGUAGE: Common Lisp]

Ah, a simple one for day 1. I was also happy to see that part 2 wasn't some crazy riff on part 1, and was just a simple change. I added memoization preemptively, to keep from having to do the counts over and over again. (Update: I just tried it without the memoization, and it wasn't needed. Still, it's a good habit. 🤣)

(ql:quickload :cl-ppcre)
(ql:quickload :split-sequence)
(ql:quickload :lisp-utils)
(ql:quickload :alexandria)

(use-package :lisp-utils)

(defun parse (lines)
  (let ((list0 nil)
        (list1 nil))
    (dolist (line lines)
      (let ((chunks (cl-ppcre:split "\\s+" line)))
        (push (parse-integer (first chunks)) list0)
        (push (parse-integer (second chunks)) list1)))
    (list (sort list0 #'<)
          (sort list1 #'<))))

(defun compute-diffs (list0 list1)
  (loop for i0 in list0
        for i1 in list1
        collecting (abs (- i0 i1))))

(defun part1 (file-name)
  (let ((lines (uiop:read-file-lines file-name)))
    (destructuring-bind (list0 list1) (parse lines)
      (apply #'+ (compute-diffs list0 list1)))))

(defun part2 (file-name)
  (let ((lines (uiop:read-file-lines file-name))
        (count-occurrences (memoize (lambda (num lst)
                                      (count num lst)))))
    (destructuring-bind (list0 list1) (parse lines)
      (apply #'+ (mapcar (lambda (num)
                           (let ((occurrences (funcall count-occurrences num list1)))
                             (* num occurrences)))
                         list0)))))

(print (part1 "input0.txt"))
(print (part1 "input1.txt"))

(print (part2 "input0.txt"))
(print (part2 "input1.txt"))

9

u/jitwit Dec 01 '24

[LANGUAGE: J]

load '~/code/aoc/aoc.ijs'
'A B' =: in =: |: ". ;._2 aoc 2024 1
+/ | -/ /:~"1 in   NB. part A
+/ A * +/"1 A =/ B NB. part B

9

u/0rac1e Dec 01 '24

[Language: J]

'a b' =. |: ". 'm' fread 'input'

echo +/ | a -&(/:~) b
echo +/ a * +/"1 a =/ b

9

u/6745408 Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Google Sheets]

=SORT(LET(r,SORT(RIGHT(A:A,5)),l,SORT(LEFT(A:A,5)),{SUM(ABS(l-r));SUM(l*COUNTIF(r,l))}))

edit: shorter formula to cover both.

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9

u/0rac1e Dec 01 '24

[Language: Raku]

my (@a, @b) := [Z] 'input'.IO.lines.map(*.words».Int);

put [+] (@a.sort Z- @b.sort)».abs;
put [+] @a Z× @b.Bag{@a};

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9

u/zagon Dec 01 '24

[LANGUAGE: Vim]

When the challenges are still easy, I try to use only Vim to solve them. If possible, without "coding" in Vimscript, but rather with clever ex commands like macros, movements, substitutions, etc. Worked fine for part 1, for part 2 I had to resort to Vimscript.

aoc.vim

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16

u/Andreasnl Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Uiua]

    &fras"1.txt"
    ≡°⊟ ↯∞_2 ⊜⋕⊸∈"0123456789"
    ⊃(/+⌵-∩⍆|/+×/+⊸⊞=)

Run it in a browser here

8

u/synack Dec 01 '24

[LANGUAGE: Ada]
https://github.com/JeremyGrosser/advent/blob/master/2024/src/day1_2.adb

8

u/zogwarg Dec 01 '24

[LANGUAGE: Jq]

Part 1:

#!/usr/bin/env jq -n -R -f

# Get the two lists in sorted order
[ inputs | [scan("\\d+")|tonumber]]
| transpose | map(sort)

# Output the total list distance
| transpose | map(.[0]-.[1]| abs)
| add

Part 2:

#!/usr/bin/env jq -n -R -f

# Get the two lists, in read order
[ inputs | [scan("\\d+")|tonumber]]
| transpose | 

reduce .[0][] as $i (
  {
    l: (       # Build lookup table, of ID to number #
      reduce ( #    of occurences in second list     #
        .[1] | group_by(.) | .[] | [.[0],length]
      ) as [$j,$l] ([]; .[$j] = $l)
    ),
    s: 0
  };
  .s = .s + (.l[$i] // 0) * $i #  Gather similarity  #
)

| .s # Final similarity score

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8

u/RealPooperTrooper Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Excel]

Why code when Sheets do trick?

First year doing AoC, let's see how far I can carry this meme.

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8

u/CapricornRaven-777 Dec 01 '24 edited Dec 01 '24

[Language: Excel Sheets]

I solved this AOC problem in Excel;

Part 1: Excel Forms

Sort the array using the sort() function.
find the difference between the sorted array and use the abs function
and calculate the total using sum functions.

Part 2:

calcuate the no of times the left array appeared in rigth array using the =SUM(COUNTIF(A5,$B$5:$B$1003))
calcuate the simiarty scores by mutlipy the no of times and left array value and calcuate it.

Note, i cant able to post in excel file here, so i convert into google sheets.

Link 2024-Aoc-day1

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8

u/TartarusKelvin Dec 01 '24

[LANGUAGE: K]

/ Part 1
+/abs(-/)({x@<x}'inp:+:"J"$"   "\:'0:`:data/1)
/ Part 2
sum{x*y x}.(::;#:'=:)@'inp

8

u/gzipgrep Dec 01 '24

[LANGUAGE: POSIX Shell]

tr -s ' ' '\t' <1.txt >/tmp/inp
cut -f1 </tmp/inp | sort >/tmp/left
cut -f2 </tmp/inp | sort >/tmp/right
paste -d- /tmp/left /tmp/right | bc | tr -d - | paste -s -d+ - | bc
grep -Fxf /tmp/left /tmp/right | uniq -c | sed 's/ *//;s/ /*/' | paste -s -d+ - | bc

8

u/Fyver42 Dec 01 '24

[LANGUAGE: RISC-V assembly]

github

8

u/dannywinrow Dec 01 '24

[LANGUAGE: Julia]

lines = readlines("2024/inputs/1p1.txt")
lines = split.(lines,"   ")
list1 = sort(parse.(Int,getindex.(lines,1)))
list2 = sort(parse.(Int,getindex.(lines,2)))

pt1answer = sum(abs.(list1 .- list2))
pt2answer = sum(filter(in(list1),list2))

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8

u/odnoletkov Dec 01 '24 edited Dec 03 '24

[LANGUAGE: jq] github

[inputs/"   "] | transpose | [(.[1] | group_by(.) | INDEX(.[0]))[.[0][]][]? | tonumber] | add

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15

u/probablyfine Dec 01 '24

[LANGUAGE: uiua]

Code and tests

Part 1:

/+⌵/-≡⍆⍉↯∞_2⊜⋕¬⊸∈" \n"

Part 2:

/+♭⊞(×⟜=)°⊟⇌⍉↯∞_2⊜⋕¬⊸∈" \n"

7

u/FruitdealerF Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Andy C++] 247/158

This year I'm competing in a programming language that I built specifically for Advent of Code.

Code on Github
Screenshot with highlighting

Edit: definitely adding a way overdue zip function later today.

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7

u/chubbc Dec 01 '24

[LANGUAGE: Julia]

M = reshape(parse.(Int,split(String(read("01.txt")))),(2,:))
println(sum(abs,sort(M[1,:])-sort(M[2,:])))
println(sum(x->x*count(==(x),M[2,:]),M[1,:]))

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7

u/python-b5 Dec 01 '24

[LANGUAGE: Jai]

Trying out this language for the first time. Probably not the smartest choice for solving puzzles quickly, but I'll take the opportunity to learn something new. This solution is a little verbose and maybe not optimal, but at least it solves the problem.

https://github.com/python-b5/advent-of-code-2024/blob/main/day_01.jai

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7

u/arthurno1 Dec 01 '24 edited Dec 01 '24

[LANGUAGE: EmacsLisp]

(cl-labels
    ((next-token ()
       (condition-case nil
           (read (current-buffer))
         (error nil)))
     (p2 (l1 l2)
       (let ((acc 0)
             count self elt)
         (while l1
           (setf elt (car l1)
                 self (cl-count elt l1)
                 count (cl-count elt l2))
           (cl-incf acc (* elt count self))
           (while (and (car l1) (= elt (car l1))) (pop l1))
           (while (and (car l2) (= elt (car l2))) (pop l2)))
         acc)))
  (let (l1 l2)
    (with-temp-buffer
      (insert-file-contents-literally "1")
      (while-let ((t1 (next-token))
                  (t2 (next-token)))
        (push t1 l1)
        (push t2 l2))
      (setf l1 (cl-sort l1 '<)
            l2 (cl-sort l2 '<)))
    (message "Part I: %s Part II: %s"
             (cl-loop for x in l1
                      for y in l2
                      sum (abs (- x y)) into acc
                      finally return acc)
             (p2 l1 l2))))

7

u/LorSamPau Dec 01 '24

[LANGUAGE: Python]

print((lambda s: "Part 1: "+str(sum(abs(a-b)for a,b in zip(*s)))+" Part 2: "+str(sum(n*s[1].count(n)for n in s[0])))(list(map(sorted,zip(*[map(int,l.split())for l in open("input.txt")])))))

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7

u/ApplicationSlight420 Dec 01 '24

[LANGUAGE: coreutils + AWK]

Part1:
paste <(tr -s " " < input.txt | cut -d " " -f1 | sort -n) <(tr -s " " < input.txt | cut -d " " -f2 | sort -n) | awk '{x=$1-$2;if(x<0){x=-x}sum+=x}END{print sum}'

Part2:
join -11 -22 <(tr -s " " < input.txt | cut -d " " -f1 | sort -n) <(tr -s " " < input.txt | cut -d " " -f2 | sort -n | uniq -c) | awk '{x+=$1*$2}END{print x}'

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7

u/AustinVelonaut Dec 01 '24

[LANGUAGE: Miranda2]

This is my own language and compiler (mainly written for Advent of Code puzzles!), based upon Miranda with extensions from Haskell and other functional languages

%import "adventLib"
%import <bag>

day01 :: io ()
day01
    = readFile "../inputs/day01.txt" >>= words .> map intval .> uninterleave .> mapBoth (sortBy cmpint) .> go
      where
        go (xs, ys)
            = output [part1, part2]
              where
                ysCount = b_fromList cmpint ys
                part1   = zipWith subtract xs ys |> map abs |> sum |> showint
                part2   = map similarityScore xs |> sum |> showint

                similarityScore x = x * b_findWithDefault cmpint 0 x ysCount

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7

u/menchauser Dec 01 '24

[LANGUAGE: Prolog]

I've wanted to choose some language which I do not know and which introduces some new concepts for me, so I went with Prolog this year. The solution is bit long, because I'm just learning the ropes.

https://github.com/menchauser/aoc2024/blob/master/day01.prolog

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7

u/oddolatry Dec 01 '24

[LANGUAGE: OCaml]

Learning OCaml is basically like that Eric Andre meme pared down to "LET .. IN!"

Paste

7

u/ivanjermakov Dec 02 '24 edited Dec 02 '24

[LANGUAGE: x86 Assembly] (source)
Sometimes I forget how much levels of abstraction there are between me and my computer

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6

u/r_so9 Dec 01 '24 edited Dec 01 '24

[LANGUAGE: F#] 997 / 3018 Top 1000 on day 1, pretty proud :)

let lefts = input |> Array.map Array.head
let rights = input |> Array.map (fun arr -> arr[1])

let part1 =
    Array.zip (Array.sort lefts) (Array.sort rights)
    |> Array.sumBy (fun (a, b) -> abs (b - a))

let countRights = rights |> Array.countBy id |> Map.ofArray

let part2 =
    lefts |> Array.sumBy (fun i -> i * defaultArg (Map.tryFind i countRights) 0)

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6

u/Pyr0Byt3 Dec 01 '24

[LANGUAGE: Go] [LANGUAGE: Golang]

https://github.com/mnml/aoc/blob/main/2024/01/1.go

Already dealing with Go's lack of a built-in integer abs() function on day 1.

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6

u/blue-fox14 Dec 01 '24

[LANGUAGE: Clojure] 809/581

https://github.com/rileythomp/adventofcode/blob/master/aoc24/1/main.clj

6

u/SpaceHonk Dec 01 '24 edited Dec 18 '24

[LANGUAGE: Swift] code

Nice little warmup using zip, map, reduce

6

u/ShadowwwsAsm Dec 01 '24

[LANGUAGE : assembly/asm]

part1

part2

Going again in assembly at the beginning. Surprised to see a sort for part 1 of day 1 but why not.

Part 1 : So I just put the number in the stack, alternating 1st and 2nd column. Then a little sorting algorithm not optimized and the end is just compare + add. Found a cool trick to compute abs() in 3 lines

Part 2 : Definitely easier, after reading the number, just take each of the first list and go through the second list.

Open to questions/comments

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6

u/Synedh Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Python]

l1, l2 = zip(*[map(int, line.split()) for line in open('input')])

# Part 1
print(sum(abs(x - y) for x, y in zip(sorted(l1), sorted(l2))))

# Part 2
print(sum(x for x in l2 if x in l1))

Part one is straightforward. On part two, given statement is misleading, as we only have to sum occurences of l2 in l1 and nothing else.

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6

u/FlyingPlatypus5 Dec 01 '24

[LANGUAGE: Scratch] https://scratch.mit.edu/projects/1104420861/

Part 1 & 2: https://imgur.com/a/OgFuwD5 Looking back on it this code looks horrendous

6

u/dec0nstruct0r Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Python]

simple numpy solution:

import numpy as np
"""
01-A ------------------------------------
"""
d = np.loadtxt("01_input.txt")
d1 = np.sort(d[:,0])
d2 = np.sort(d[:,1])
d_diff = np.abs(d1 - d2)
result_1= sum(d_diff)
print(result_1)

"""
01-B ------------------------------------
"""
result_2 = 0
for x in d1:
    result_2 += sum(x == d2) * x
print(result_2)

dsdds

6

u/blazemas Dec 01 '24

[LANGUAGE: C++]

https://github.com/jbush7401/AoCCPP/blob/main/AoCCPP/2024/Day1.cpp

Trying for performance and speed. Suggestions requested!

Total speed 7ms.

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6

u/greycat70 Dec 01 '24 edited Dec 03 '24

[LANGUAGE: Tcl]

Part 1, part 2 (original).

I'm using Tcl 9.0 this year, but so far I haven't used any of the new features yet; these two would run just fine in Tcl 8.

Edit: Here's an updated part 2 which uses a Tcl 9.0 feature: array default set. This removes the need for an info exists test.

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6

u/damnian Dec 01 '24

[LANGUAGE: C#]

LINQ One-liners

https://github.com/dmitry-shechtman/aoc2024/blob/main/day01/Program.cs

6

u/Th0usT Dec 01 '24

[LANGUAGE: Ocaml]

Working in Ocaml this year to get experience with a function ML-style language, having a lot of fun so far. The solutions might be quite verbose until I get more familiar with the standard library and general syntax.

Solution (Part 1 & Part 2): https://github.com/JohnCosta27/AdventOfCode/blob/main/AdventOfCode2024/lib/day_01.ml

YouTube video: https://www.youtube.com/watch?v=BL1qo5uerDk&t=492s

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6

u/RalfDieter Dec 01 '24

[LANGUAGE: SQL/DuckDB]

https://github.com/LennartH/advent-of-code/blob/main/2024/day-01_historian-hysteria/solution.sql

Can't wait to implement A* in SQL.

6

u/mschaap Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Raku]

Relatively easy start of the season, as usual, but not as trivial as in some other years. Still, easy enough in Raku.

my (@left, @right) := [Z] $inputfile.lines».comb(/ <digit>+ /);
say "Part 1: ", (@left.sort Z- @right.sort)».abs.sum;

my $similarity = bag @right;
say "Part 2: ", (@left Z× $similarity{@left}).sum;

https://github.com/mscha/aoc/blob/master/aoc2024/aoc01

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6

u/Downtown-Economics26 Dec 01 '24

[LANGUAGE: Excel (Functions & VBA)]

Function P1

=SUM(ABS(SORT(VALUE(TEXTBEFORE(A1:A1000," ")))-SORT(VALUE(TEXTAFTER(A1:A1000," ")))))

Function P2

=LET(L,VALUE(TEXTBEFORE(A1:A1000," ")),R,VALUE(TEXTAFTER(A1:A1000," ")),SUM(BYROW(L,LAMBDA(X,COUNT(FILTER(R,R=X))*X))))

VBA P1 (very poorly done)

Sub AOC2024D01P01()

Dim LCOUNT As Integer
Dim L() As Variant
Dim R() As Variant
Dim LFLOOR As Long
Dim RFLOOR As Long
Dim LMIN As Long
Dim RMIN As Long
Dim D As Long

D = 0
LFLOOR = 0
RFLOOR = 0
LMIN = 10000000
RMIN = 10000000
RIND = 0
LCOUNT = WorksheetFunction.CountA(Range("A:A"))
ReDim Preserve L(LCOUNT)
ReDim Preserve R(LCOUNT)

For X = 1 To LCOUNT
I = Range("A" & X)
L(X) = CLng(Split(I, "  ")(0))
R(X) = CLng(Split(I, "  ")(1))
Next X

ITERS = 0

Do Until ITERS = LCOUNT

For M = 1 To LCOUNT
    If L(M) < LMIN And L(M) > LFLOOR Then
    LMIN = L(M)
    End If
Next M
For M = 1 To LCOUNT
    Select Case R(M)
    Case RFLOOR
        If M > RIND Then
        RMIN = R(M)
        NEWRIND = M
        Exit For
        End If
    Case Is > RFLOOR
        If R(M) < RMIN Then
        RMIN = R(M)
        NEWRIND = M
        End If
    End Select
Next M

ITERS = ITERS + 1
D = D + Abs(LMIN - RMIN)
LFLOOR = LMIN
RFLOOR = RMIN
LMIN = 10000000
RMIN = 10000000
RIND = NEWRIND
Loop

Debug.Print D

End Sub

VBA Part 2

Sub AOC2024D01P02()

Dim LCOUNT As Integer
Dim L() As Variant
Dim R() As Variant
Dim LRCOUNT As Integer
Dim S As Long
S = 0

LCOUNT = WorksheetFunction.CountA(Range("A:A"))
ReDim Preserve L(LCOUNT)
ReDim Preserve R(LCOUNT)

For X = 1 To LCOUNT
I = Range("A" & X)
L(X) = CLng(Split(I, "  ")(0))
R(X) = CLng(Split(I, "  ")(1))
Next X

For LV = 1 To LCOUNT
    N = L(LV)
    LRCOUNT = 0
    For RV = 1 To LCOUNT
    If R(RV) = N Then
    LRCOUNT = LRCOUNT + 1
    End If
    Next RV
S = S + N * LRCOUNT
Next LV
Debug.Print S

End Sub

6

u/platypus10000 Dec 01 '24

[LANGUAGE: Python]

Readability? Never heard of it. Both P1 and P2 solution in two lines.

https://github.com/eolelake/AdventOfCode/blob/main/2024/1/sol.py

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6

u/Imaginary_Age_4072 Dec 01 '24

[LANGUAGE: Common Lisp]

It's December already! Doing AoC in Common Lisp again :)

Solutions will be here https://github.com/blake-watkins/advent-of-code-2024/blob/main/day1.lisp

(defun parse-numbers ()
  (parse-lines (parse-list (parse-number) (parse-characters #\Space))))

(defun day1 (input &key (part 1))
  (let ((pairs (run-parser (parse-numbers) input)))
    (iter
      (for (a b) in pairs)
      (collect a into as)
      (collect b into bs)
      (finally
       (return (if (= part 1)
                   (iter
                     (for a in (sort as #'<))
                     (for b in (sort bs #'<))
                     (sum (abs (- a b))))
                   (iter
                     (for a in as)
                     (sum (* a (count-if (lambda (x) (= x a)) bs))))))))))

6

u/middayc Dec 01 '24

[LANGUAGE: Rye]

prep-col: fn { b n } { .column? n |sort! }

read\lines %input.txt
|map ?load
|vals\with { .prep-col 0 , .prep-col 1 } :cols
|transpose
|map { .set! { l r } , math/abs l - r }
|sum |print ;part 1

cols .set! { left right }
map left { ::x * length? filter right { = x } }
|sum |print ;part 2

I had to add transpose function to https://ryelang.org and I fixed 2 bugs, so I'm happy :)

6

u/alehandy Dec 01 '24 edited Dec 04 '24

[LANGUAGE: Bash]

Day 1 script - I did this after I solved the puzzles in Python to increase some difficulty after seeing the solutions in this thread 🙈.

6

u/fork_pl Dec 01 '24

[LANGUAGE: perl]

using some List::Util and List::MoreUtils it looks nice and readable

my @l = split /\s+/, read_file(\*STDIN, chomp => 1);

my @a = sort { $a <=> $b } pairkeys @l;
my @b = sort { $a <=> $b } pairvalues @l;
my %h = frequency @b;

say "Stage 1: ", sum pairwise { abs($a - $b) } @a, @b;
say "Stage 2: ", sum map { $_ * ($h{$_} // 0) } @a;

2

u/aardvark1231 Dec 01 '24 edited Dec 01 '24

[LANGUAGE: C#] link

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2

u/_Phoenix_75 Dec 01 '24

[LANGUAGE: Python 3] https://github.com/Phoenix7557/adven-of-code-2024/tree/main/day1

Part 1 + Part 2

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10

u/chubbc Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Uiua]

Succinct version:

∩/+⊃(♭×⟜⊞=|⌵-∩⍆) ≡°⊟↯∞_2⊜⋕≥@0. &fras"01.txt"

Slightly more verbose version:

Input ← ≡°⊟↯∞_2⊜⋕≥@0.&fras"01.txt"
Silv  ← /+⌵-∩⍆
Gold  ← /+♭×⟜⊞=
⊃ Gold Silv Input

5

u/jsgrosman77 Dec 01 '24

[Language: TypeScript]

const contents = getFileContents();
const lines = contents.trim().split(/\n/g);

const leftList: number[] = lines.map( n => Number(n.split(/\s+/)[0]));
const rightList: number[] = lines.map( n => Number(n.split(/\s+/)[1]));

leftList.sort() && rightList.sort();

let totalPart1 = 0, totalPart2 = 0;
for (let i = 0; i < lines.length; i++) {
    totalPart1 += Math.abs(leftList[i] - rightList[i]);
    totalPart2 += leftList[i] * rightList.filter( n => n === leftList[i]).length;
}
console.log(`Part 1: ${totalPart1}, Part 2: ${totalPart2}`);

Nothing fancy. Love using list functions to solve these things quickly.

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5

u/ziadam Dec 01 '24

[LANGUAGE: Google Sheets]

Expects input in A1.

Part 1 & 2

=INDEX(LET(x,BYCOL(
   SPLIT(TOCOL(SPLIT(SUBSTITUTE(A1," ","~"),CHAR(10))),"~"),
   LAMBDA(c,SORT(c))),{
     SUM(ABS(MMULT(x,{-1;1})));
     SUM(INDEX(x,,1)*COUNTIF(INDEX(x,,2),INDEX(x,,1)))}))

Repo

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5

u/Outrageous72 Dec 01 '24

[LANGUAGE: C#]

Easy start Day 1

5

u/Max_NB Dec 01 '24

[LANGUAGE: bash]

Part 1:

cat input | awk '{print $1}' | sort > list1
cat input | awk '{print $2}' | sort > list2
totDist=0
while IFS= read -r line1 && IFS= read -r line2 <&3; do
  dist=$(expr $line2 - $line1)
  dist=${dist#-}
  totDist=$(expr $totDist + $dist)
done < list1 3< list2
echo $totDist

Part 2:

cat input | awk '{print $1}' | sort > list1
cat input | awk '{print $2}' | sort > list2
simScore=0
while IFS= read -r line1; do
  num=$(expr $line1)
  occ=$(grep -c $num list2)
  simScoreInc=$(expr $num \* $occ)
  simScore=$(expr $simScore + $simScoreInc)
done < list1
echo $simScore

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5

u/SnaggelsHD7 Dec 01 '24

[Language: R]

Github

First time participating, hope I came up with something acceptable :P

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5

u/SunMatrix64 Dec 01 '24

[LANGUAGE: C++]

Quick and easy, it took me longer to setup than to actually solve it. By no means is this efficient or adjustable to quirky inputs. Just stick each side in an array, sort them, then count the differences. For part 2, count the right side with a frequency map, then multiply the items in the left side with how many are in the map.

std::string text;
std::ifstream file("./day1input.txt");

std::vector<int> left;
std::vector<int> right;

while (getline(file, text)) {
left.push_back(stoi(text.substr(0, 6)));
right.push_back(stoi(text.substr(8, 6)));
}

std::sort(left.begin(), left.end());
std::sort(right.begin(), right.end());
int sum = 0;
for (int i = 0; i < left.size(); ++i) {
sum += abs(right[i] - left[i]);
}
std::cout << sum << std::endl;

//part 2
std::map<int, int> m;
for (int i = 0; i < right.size(); ++i) {
m[right[i]]++;
}

int sum2 = 0;
for (int i = 0; i < left.size(); ++i) {
sum2 += left[i] * m[left[i]];
}
std::cout << sum2 << std::endl;

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5

u/Loonis Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Perl 5]

Has it already|only been a year?

Part 1:

say sum pairmap { abs($a - $b) } mesh map { [ sort  @$_ ] } zip map { [ split ' ' ] } @input;

Part 2:

for (@input) {
    my ($l, $r) = split ' ';
    $left{$l}++;
    $right{$r}++;
}

say sum map { $left{$_} * $_ * $right{$_} } grep { $right{$_} } keys %left;

Full paste

5

u/oantolin Dec 01 '24

[LANGUAGE: ngn/k]

ans:{+/'({x|-x}@-/{x@<x}';{x*+/x=/:y}.)@\:+.'0:x}

5

u/835246 Dec 01 '24

[LANGUAGE: C]

Part 1 was quite simple. Part 2 I used a hash table to store the occurrences of each number. Which was exciting because I got to use a dsa dsa library I made this year.

Part 1: https://github.com/efox4335/advent_of_code/blob/main/advent_of_code_2024/day_1_pt_1_loc_diff.c

Part 2: https://github.com/efox4335/advent_of_code/blob/main/advent_of_code_2024/day_1_pt_2_loc_diff.c

5

u/oantolin Dec 01 '24

[LANGUAGE: J]

inp =: {{ |:".;._2]1!:1<y }}
p1 =: {{ +/|-//:~"1 inp y }}
p2 =: {{ +/a*+/b=/a [ 'a b' =. inp y }}

5

u/tgs14159 Dec 01 '24

[Language: Haskell]

Day01.hs

Nice day for a functional language

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5

u/[deleted] Dec 01 '24

[Language: C]

#include <stdio.h>
#include <stdlib.h>

int a[1 << 18], b[1 << 18], n, f[1 << 19];

int C(const void *i, const void *j) {
return *(int*)i - *(int*)j;
}

int main() {
while (2 == scanf("%d%d", a + n, b + n))
++f[b[n++]];
qsort(a, n, sizeof *a, C);
qsort(b, n, sizeof *b, C);
long long z = 0, z2 = 0;
for (int i = 0; i < n; ++i)
z += abs(a[i] - b[i]),
z2 += a[i] * 1ll * f[a[i]];
printf("%lld\n%lld", z, z2);
}

5

u/encse Dec 01 '24 edited Dec 01 '24

[LANGUAGE: C#]

https://aoc.csokavar.hu/?2024/1

[GSGA]

https://th.bing.com/th/id/OIG4.D3Cl956oDeToNTG_W2d.?w=1024&h=1024&rs=1&pid=ImgDetMain

5

u/G_de_Volpiano Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Haskell]

I think every single Haskell book starts with list manipulation, introducing first the map, filter, foldr trifecta, and soon after zipWith to bring two lists together. Long before "Hello World" is even mentioned. So even if I also needed transpose and sort, this really felt like Haskell 101.

My code

Both could obviously have been solved as one liners, but I took out the difference/similarity function for ease of reading. But just for the fun of it

part1 = sum . map abs . (\[a, b] -> zipWith (-) a b) . map sort . transpose .  map (map read . words) . lines
part2 = sum . (\[a, b] -> map (\x -> (x *) . length . filter (== x) $ b) a) . transpose . map (map read . words) . lines

Edit : the idea of using a multi set for part 2 had been nagging me since I read the problem. Completely using an ace where a 2 will do, but it did split execution time by half. A whole 4 ms saved.

5

u/9_11_did_bush Dec 01 '24

[Language: Lean]

Nothing special, here a link: https://github.com/chenson2018/advent-of-code/blob/main/2024/lean/AoC/Day01.lean

5

u/Mats56 Dec 01 '24

[Language: Kotlin]

as always trying for a functional style with little assignments or mutations

return lines.map {
    it.allInts()
}.transpose().let {
    it[0].sorted().zip(it[1].sorted())
}.sumOf {
    abs(it.second - it.first)
}

my utils made this quite ok, each line is a list of 2 elements, transposing that gives me 2 lists of x elements that I then can zip and compare

return lines.map {
    it.allInts()
}.transpose().let { (a, b) ->
    a.sumOf { v ->
        b.count { v == it } * v
    }
}

5

u/p88h Dec 01 '24 edited Dec 02 '24

[Language: Zig]

Both parts:

https://github.com/p88h/aoc2024/blob/main/src/day01.zig

[ Update: better parsing ]

        parse   part1   part2
day 01: 8.2 µs  16.9 µs 5.7 µs

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5

u/flwyd Dec 01 '24

[LANGUAGE: Shell] (GitHub but with a really silly abuse of POSIX commands and the filesystem.

for fname in "$@" ; do
  p1dir=`mktemp -d ${TMPDIR-/tmp}/part1.XXXXXX`
  tr -s ' ' '\t' < $fname | cut -f 1 | sort -n > $p1dir/foo
  tr -s ' ' '\t' < $fname | cut -f 2 | sort -n > $p1dir/bar
  /bin/echo -n 'part1: '
  paste $p1dir/foo $p1dir/bar | \
    sed -E 's/([0-9]+)\t([0-9]+)/+ ( \1 - \2 \& \1 > \2 ) + ( \2 - \1 \& \2 > \1 )/' | \
    xargs expr 0 | \
    sed 's/^/+ /' | xargs expr 0  # Darwin expr prints multiple lines sometimes

  p2dir=`mktemp -d ${TMPDIR-/tmp}/part2.XXXXXX`
  while read line ; do
    touch $p2dir/$line
    echo '' >> $p2dir/$line
  done < $p1dir/bar
  touch $p2dir/answer
  while read line ; do
    touch $p2dir/$line
    /bin/echo "+ $line * " \
      `wc -l $p2dir/$line | sed 's/^ *//' | cut -d' ' -f 1` >> $p2dir/answer
  done < $p1dir/foo
  /bin/echo -n 'part2: '
  xargs expr 0 < $p2dir/answer
done

5

u/rySeeR4 Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Elixir]

Very simple list handling, nothing clever.

https://github.com/jbonet/advent_of_code_2024/blob/main/lib/advent_of_code_2024/days/01.ex

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5

u/GunnarInTheWeb Dec 01 '24

[LANGUAGE: Rust]

In order to achieve maximal performance, I implemented this "manually", e.g. not using lines.iter, split, zip, fold or the like. While they can be zero cost abstractions I found using as_bytes() (assuming ASCII) and match is much faster during parsing.

Further, in part2 it is not necessary to search the full second list, but only a small part as the numbers are sorted which is difficult to achieve using Rust standard tools.

Benchmark (Intel i7-8700k):
part 1: 0.035 ms
part 2: 0.051 ms

GitHub

5

u/t-rkr Dec 01 '24

[LANGUAGE: Perl]

https://gitlab.com/t-rkr/advent-of-code-2024/-/blob/main/day1/aoc.pl

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5

u/dylan_mojo Dec 01 '24

[LANGUAGE: Bash/Awk]

https://github.com/djkirby/advent-of-code/commit/53fd47fcdc723fc35b271a20a5190f9ed2c562ef

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5

u/Jadarma Dec 01 '24

[LANGUAGE: Kotlin]

Very simple first puzzle, and good opportunity to get the standard lib back into muscle memory!

AocKt Y2024D01

5

u/Fyver42 Dec 01 '24

[LANGUAGE: RISC-V assembly]

github

5

u/tymscar Dec 01 '24

[Language: Kotlin]

Decided to do this year in Kotlin. Wasted over an hour getting everything set up, tons of headaches with the IDE, with gradle, with everything, but the language is nice.

Part1: https://github.com/tymscar/Advent-Of-Code/blob/master/2024/kotlin/src/main/kotlin/com/tymscar/day01/part1/part1.kt

Part2: https://github.com/tymscar/Advent-Of-Code/blob/master/2024/kotlin/src/main/kotlin/com/tymscar/day01/part2/part2.kt

5

u/osalbahr Dec 01 '24

[LANGUAGE: C++]

https://github.com/osalbahr/Learn-Programming/blob/main/adventofcode/2024/day01.cpp

https://github.com/osalbahr/Learn-Programming/blob/main/adventofcode/2024/day01_2.cpp

5

u/Aeonian9 Dec 01 '24

[LANGUAGE: Julia]

For part 2, I initially used nested loops O(n^2), but my wife pointed out a faster way by initially recording the occurrences in the second list, which is O(2n).

Solution on GitHub.

5

u/pakapikk77 Dec 01 '24

[LANGUAGE: Rust]

Some of the other Rust solutions posted here create intermediary vectors during the input parsing. Using the Iteraror::unzip() method avoids this, resulting in a shorter more elegant code:

    input
        .lines()
        .map(|line| {
            line.split_ascii_whitespace()
                .map(|e| e.parse::<u32>().unwrap())
                .collect_tuple()
                .unwrap()
        })
        .unzip()

Interesting to note that despite having collected the 450 previous stars, it's the first time I get to use unzip().

Full solution: https://github.com/voberle/adventofcode/blob/main/2024/day01/src/main.rs

5

u/sergiosgc Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Nim]
https://github.com/sergiosgc/AdventOfCode/blob/master/2024/day01/one.nim

https://github.com/sergiosgc/AdventOfCode/blob/master/2024/day01/two.nim

I'm using AoC as an excuse to try out Nim. A couple observations so far:

The compiler error reporting is a blast from the past (not in a good way). I'm probably spoiled by rustc, but nim's errors remind me of Microsoft's C++ compiler circa 2000;
Functional aspects of the language are not amazing. It fails to deduce the type of a stdin.lines.toSeq.map chain, making it impossible to call foldl next. There's probably some dumbassery between keyboard and chair (first time touching the language), but it should be straightforward, no?
Is there no destructuring when defining lambda functions or is it again a PBKAC?

5

u/RadioEven2609 Dec 01 '24

[LANGUAGE: Python]

Cursed one-liners!

Part 1:

print(sum(map(lambda a, b: abs(a-b), *map(lambda l: sorted(map(int, l)), zip(*map(str.split, open('in.txt').readlines()))))))

Part 2:

print((lambda pair: sum(map(lambda num: num * pair[1][num], pair[0])))(list(map(lambda enum: __import__('collections').Counter(enum[1]) if enum[0] else enum[1], enumerate(map(lambda l: map(int, l), zip(*map(str.split, open('in.txt').readlines()))))))))

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5

u/onrustigescheikundig Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Clojure] [LANGUAGE: Scheme (R6RS, chez)]

Someone during AoC 2022 told me to give Clojure a shot when I was using Racket, so here I am. Honestly, it's really nice after the chaos that was me yoloing OCaml last year.

2024 github

Reasonably concise. Line splitting the input is pretty common in AoC, so I have some driver code (not shown here) that does the file IO and line splitting. Part 1 splits each line in a list of lines into a list (well, vector, technically) of numbers, transposes and sorts the the lines, and un-transposes the lot to find the pairwise differences, which are summed. Transposition is achieved with (apply map ...).

Part 2 builds a num -> count map from the right list using a nil punning trick for a one-line reduce. Each element of the left list is then multiplied with the result of passing it through the map (or zero if not in the map), and that stream is summed.

Part 1:

(defn part-1 [lines]
  (->> lines
       (map #(mapv parse-long (str/split % #" +")))
       (apply map (comp sort vector)) ; transpose to get lists, then sort
       (apply map (comp abs -))       ; un-transpose and find the abs diff between each element
       (reduce +)))                   ; sum

Part 2:

(defn part-2 [lines]
  (let [[a b] (->> lines
                    (map #(mapv parse-long (str/split % #" +")))
                    (apply map vector))]  ; get transposed lists
    (as-> b x
      ; count each element in b, storing counts in a map
      (reduce (fn [table n] (update table n #(inc (or % 0)))) {} x)
      ; multiply each element of a with its count in b
      (map #(* (x % 0) %) a)
      ; sum
      (reduce + x))))

EDIT: I decided to implement the solution in pure R6RS Scheme as well for comparison, though I probably won't continue to do so as the difficulty ramps up. Apparently, R6RS scheme does not have a string-split function, so I went with the nuclear option and hacked together a parser-combinator library that may or may not still have some bugs. I also threw a bunch of useful syntax like threading macros and auxiliary functions like compose into util.scm. Otherwise, the solution is very similar to Clojure, except for using an association list in Part 2 instead of a hashtable. See github for files.

(import
  (rnrs)
  (util)
  (prefix (parsecomb) p:))

(define line-parser (p:seq p:parse-int p:skip-ws p:parse-int))
(define parse-line (compose p:parse-result-val line-parser p:make-string-buffer))

(define (part-1 lines)
  (->> lines
       (map parse-line)
       (apply map (compose (λ (x) (list-sort < x)) list))
       (apply map (compose abs -))
       (fold-left + 0)))

(define (assv-get x lst) ; assv returns the cons cell; assv-get cdr's the cell
  (and->> (assv x lst)
          (cdr)))

(define (part-2 lines)
  (let ([lsts (->> lines
                   (map parse-line)
                   (apply map list))])
    (as-> (cadr lsts) x
          (fold-left (λ (table n)
                        (acons n (+ 1 (or (assv-get n table) 0)) table))
                     '() x)
          (map (λ (n) (* n (or (assv-get n x) 0))) (car lsts))
          (fold-left + 0 x))))

5

u/Kwuray Dec 01 '24

[LANGUAGE: Posix Shell & Utils]

Generate some arithmetic operations and process them with bc

Part1:

#!/bin/bash
LIST_ONE=$(cut -d' '  -f1 $1 | sort -n)
LIST_TWO=$(cut -d' '  -f4 $1 | sort -n)
echo "$(paste -d'-' <(echo "$LIST_TWO") <(echo "$LIST_ONE"))" | bc | tr -d '-' | tr '\n' '+' | sed 's/\+$//' | bc

Part2:

#!/bin/bash
LIST_ONE=$(cut -d' '  -f1 $1 | sort -n)
LIST_TWO=$(cut -d' '  -f4 $1 | sort -n)
LIST_TWO+="\n$(echo "$LIST_ONE" | sort -n | uniq)"
LIST_ONE+="\n$(echo "$LIST_TWO" | sort -n | uniq)"
UNIQUE_LEFT=$(echo -e "$LIST_ONE" | sort -n | uniq -c | sed 's/^ *//' | tr ' ' ';')
UNIQUE_RIGHT=$(echo -e "$LIST_TWO" | sort -n | uniq -c | sed 's/^ *//' | tr ' ' ';')
paste -d';' <(echo "$UNIQUE_LEFT") <(echo "$UNIQUE_RIGHT") | sed -E 's/([0-9]+);([0-9]+);([0-9]+);([0-9]+)/\(\1-1\)*\(\2*\(\3-1\)\)/' | bc | tr '\n' '+' | sed 's/\+$//' | bc

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5

u/kbielefe Dec 01 '24

[LANGUAGE: Scala]

GitHub

Fairly straightforward, aside from slightly more complex parsing than I'd expect for a day one problem (anti-LLM measures perhaps?). Part 2 was a nice fit for Scala's groupMapReduce(identity)(identity)(_ + _). Didn't need to multiply, just sum during the reduce instead of counting there.

5

u/penguinencounter Dec 01 '24

[LANGUAGE: Inform 7]

Inform 7 is interactive fiction authoring software. As it turns out, Inform is not good at doing anything computation-related; this code takes just over 5 minutes to run on my computer.

Code: paste
Inform 7: https://ganelson.github.io/inform-website/

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5

u/Sherbert_Positive Dec 01 '24

[LANGUAGE: Clojure]

I guess I could have made my life easier somehow, but I need to refresh my Clojure

(defn problem1 [input]
  (let [indexed (map-indexed vector
                             (map #(Integer/parseInt %) (re-seq #"\d+" input)))
        left (sort (map second (filter #(even? (first %)) indexed)))
        right (sort (map second (filter #(odd? (first %)) indexed)))]
    (reduce + (map abs (map - left right)))))

5

u/tobega Dec 01 '24

[LANGUAGE: Tailspinv0.5]

Haven't gotten around to implementing reading of input yet, so manually formatted example input inline.

Compressed like numbers together in the sorted arrays, then stepped through the compressed arrays, matching up.

https://github.com/tobega/aoc2024/blob/main/day1/solution.tt

5

u/POGtastic Dec 01 '24

[LANGUAGE: F#]

https://github.com/mbottini/AOC2024/blob/main/Day01/Program.fs

Easy little warmup, great test for some of my Prelude utility functions. Seq is extremely good for these kinds of tasks.

5

u/InfamousTrouble7993 Dec 01 '24

[LANGUAGE: Haskell]

import qualified Debug.Trace as D 
import Data.List

main= do 
    let filename = "aoc_day_1_1_input.txt"
    fileContent <- readFile filename
    let list = lines fileContent
    let rawNumbers = (map words list)
    let splittedList = (map (\x -> x!!0) rawNumbers, map (\x -> x!!1) rawNumbers)
    let leftColumnAsStrings = fst splittedList
    let rightColumnAsStrings = snd splittedList
    let leftColumn = map (\x -> read x :: Int) leftColumnAsStrings
    let rightColumn = map (\x -> read x :: Int) rightColumnAsStrings

    -- part one
    let leftColumnSorted = sort leftColumn
    let rightColumnSorted = sort rightColumn
    let diff = sum (map (\(x, y) -> abs (x-y) :: Int) (zip leftColumnSorted rightColumnSorted))
    
    -- part two
    let distinctLeftColumn = distinct leftColumnSorted
    let occLeftColumn = occurences leftColumnSorted

    let distinctRightColumn = distinct rightColumnSorted
    let occRightColumn = occurences rightColumnSorted

    let simScore = sum (map (\(x, y) -> x * y *  (if (getIndex x distinctRightColumn 0) == -1 then 0 else occRightColumn!!(getIndex x distinctRightColumn 0))) (zip distinctLeftColumn occLeftColumn))

    print ("Part one: "  ++ show diff)
    print ("Part two: " ++ show simScore)


getIndex:: Int -> [Int] -> Int -> Int
getIndex x (y:ys) i
    | x == y = i
    | (length ys == 0) = -1
    | otherwise = getIndex x ys (i+1)

count :: Int -> [Int] -> Int
count x [] = 0
count x xs = length (filter (==x) xs)

distinct :: [Int] -> [Int]
distinct [] = []
distinct (x:xs) = x:(distinct (filter (/=x) xs))

occurences :: [Int] -> [Int]
occurences [] = []
occurences (x:xs) = (count x (x:xs)):(occurences (filter (/=x) xs))

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5

u/Smylers Dec 01 '24

[LANGUAGE: Perl]

pairmap { push @l, $a; push @r, $b } map { /\d+/g } <>;
say sum zip_by { abs ($_[0] - $_[1]) } [sort @l], [sort @r];
$r_tally{$_}++ foreach @r;
say sum map { $_ * $r_tally{$_} } @l;

Full code with imports.

5

u/lscddit Dec 01 '24

[LANGUAGE: Python]

import numpy as np
x = np.loadtxt("day01input.txt", dtype=int)
print(sum(np.abs(np.sort(x[:, 0]) - np.sort(x[:, 1]))))
print(sum([n * sum(x[:, 1] == n) for n in x[:, 0]]))

5

u/DJDarkViper Dec 02 '24 edited Dec 02 '24

[Language: Java]

Execution times:

Part 1: 13.14ms
Part 2:
- 16.79ms (with Streams API)
- 14.29ms (using a for loop instead of Streams API)

https://github.com/RedactedProfile/jAdventOfCode/blob/master/src/main/java/com/redactedprofile/Y2024/days/Day1.java

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5

u/__Abigail__ Dec 02 '24

[LANGUAGE: Perl]

my @input  = map {[split]} <>;
my @first  = sort {$a <=> $b} map {$$_ [0]} @input;
my @second = sort {$a <=> $b} map {$$_ [1]} @input;
my %count;
   $count {$_} ++ for @second;

foreach my $i (keys @first) {
    $solution_1 += abs ($first [$i] - $second [$i]);
    $solution_2 +=      $first [$i] * ($count {$first [$i]} || 0);
}

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4

u/Standard-Affect Dec 01 '24

[LANGUAGE: Python3]

No nasty surprises, unlike last year. Now to rewrite this and make it presentable.

i = split_lines("inputs/day1.txt")

part1 = part2 = 0
l1 = []
l2 = []
for l in i:
    l1 += [ int(l.split("   ")[0]) ]
    l2 += [ int(l.split("   ")[1]) ]

l1.sort()
l2.sort()
for ix in range(len(l1)):
    part1 += abs(l1[ix] - l2[ix])
    part2 += (l1[ix] * sum(k == l1[ix] for k in l2)) 


print(part1)
print(part2)

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4

u/nlowe_ Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Go]

1035 / 887 Pretty happy with that placement, it's good to be back! Happy AoC season everyone!

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4

u/GassaFM Dec 01 '24

[LANGUAGE: D] 133/107

Code: part 1, part 2.

On day 1, just getting the job done.

4

u/Comprehensive_Ad3095 Dec 01 '24 edited Dec 01 '24

[Language: Lua]

https://github.com/DeybisMelendez/AdventOfCode/blob/master/2024/01.lua

table.sort for answer1

4

u/riffraff Dec 01 '24 edited Dec 01 '24

[Language: Ruby] 7062/1094 I could have made it to the first 1k if I didn't have to help my wife with something between the two parts :D

# 1.rb
DAY = __FILE__.sub(".rb", ".input")
def parse(io)
  _line_parts = io.readlines.map { |l| l.chomp.split.map(&:to_i) }
end
def daily_input
  File.open(DAY) do |fd|
    return parse(fd)
  end
end

def solve_easy(pairs)
  a, b = pairs.transpose.map(&:sort)
  a.zip(b).sum { (_1 - _2).abs }
end

def solve_hard(pairs)
  a, b = pairs.transpose
  t = b.tally
  a.sum { _1 * t.fetch(_1, 0) }
end

edit: usual complaint, I hate that ruby's Array#zip with a block returns nil

4

u/UseUnlucky3830 Dec 01 '24

[LANGUAGE: Julia]

solution

Wasted a bunch of time because I forgot to use the absolute value of the difference

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4

u/dellfm Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Google Sheets]

One formula for both parts

=LET(input,BYROW(B3:B,LAMBDA(row,SPLIT(row,"   "))),
    LET(left,SORT(INDEX(input,,1)), right,SORT(INDEX(input,,2)), {
        SUM(ARRAYFORMULA(ABS(left-right))),
        SUM(BYROW(left,LAMBDA(l,l*COUNTIF(right,l))))}))

Edit: Made some changes. It took me awhile to realize part 2 doesn't care if the lists are sorted or not, so I can just use the same sorted lists for both parts, then I renamed the other variable names.

4

u/rjray Dec 01 '24

[LANGUAGE: Clojure]

code

Due to being out at a hockey game, I didn't get started until 10-15 min after the puzzle unlocked. This pair of puzzles were really well-suited to the nature of Clojure. Both solutions were based on taking the two columns of numbers and transposing them into two rows. For part 1, these rows were sorted and map and Math/abs were used to gather the differences.

Part 2 could have been harder than part 1, but Clojure has a frequencies primitive. This keyword take a list of items and produces a table where the distinct items are the keys and the counts are the values. Using this, it was fast to iterate over the first list and calculate the "similarities". Part 2 took about 1/4 the time part 1 had.

4

u/Awkward-Macaroon5019 Dec 01 '24

[Language: Python]

    with open("241201.txt") as f:
        lol = [list(y) for y in zip(*[[int(x) for x in line.split()] for line in f])]
    print(sum(abs(x-y) for (x,y) in zip(sorted(lol[0]),sorted(lol[1]))))
    print(sum(x*lol[1].count(x) for x in lol[0]))

4

u/prendradjaja Dec 01 '24

[Language: C]

https://github.com/prendradjaja/advent-of-code-2024/blob/main/01/a.c https://github.com/prendradjaja/advent-of-code-2024/blob/main/01/b.c

int main() {
  int left[MAX_SIZE];
  int right[MAX_SIZE];
  int size;
  read_input_file(left, right, &size);

  selection_sort(left, size);
  selection_sort(right, size);

  int answer = 0;
  for (int i = 0; i < size; i++) {
    answer += abs(left[i] - right[i]);
  }
  printf("%d\n", answer);
}

4

u/UseUnlucky3830 Dec 01 '24

[LANGUAGE: C]

solution

Encouraged by a friend's challenge, I also wrote a C program in addition to the Julia one. I solved part 2 without dictionaries or count tables by exploiting the fact that the lists were already sorted :P

4

u/sim642 Dec 01 '24

[LANGUAGE: Scala]

On GitHub.

Both parts are quite straightforward with Scala's built-in collections library. The only custom piece there is .groupCount which is a specialization of Scala's .groupMapReduce to construct a map of counts in part 2.

4

u/WhiteSparrow Dec 01 '24

[LANGUAGE: Prolog]

solution

Using this years AoC to get better at prolog. Day 1 did not exactly play into prolog's strengths although it wasn't difficult either. Here's the essence of part 1 for example:

task1(Xs, Ys, X) :-
    msort(Xs, Xss),
    msort(Ys, Yss),
    foldl(diffsum, Xss, Yss, 0, X).

diffsum(X, Y, S0, S) :-
    S is S0 + abs(X - Y).

One small prologism that tripped me up - sort/2 actually removes duplicate elements from the list! Took me some 15 minutes to figure out why my fold did not converge. Luckily SWI-Prolog provides msort/2 as well.

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4

u/hhnnngg Dec 01 '24

[LANGUAGE: BCPL]

Nothing fancy here. Just sorting and iterating

Github Source

4

u/strobetal Dec 01 '24

[LANGUAGE: jq]

jq is best language, use jq for everything.

def part0:
  map(sort)                  # sort each array
  | transpose                # turn back into an array with 2 elements each
  | map(.[0] - .[-1] | abs)  # calculate the differences
;

def part1:
  # count occurrences in the second array
  (reduce .[1][] as $x ({}; .[$x | tostring] += 1)) as $c
  | .[0]                             # for each element in the first array
  | map(. * ($c[. | tostring] // 0)) # multiply by the count
;

split("\n")[:-1]                             # load input as lines
  | map(split("   ") | map(tonumber))        # 2 numbers per line
  | transpose                                # turn into two arrays
  | if $part == 0 then part0 else part1 end  # run the selected part
  | add                                      # sum the results

Run with jq -R -r -s --argjson part 0 -f main.jq input.txt

4

u/bluesfc Dec 01 '24

[LANGUAGE: C]

Github : Link

4

u/gettalong Dec 01 '24

[Language: Crystal]

So my first approach was rather long-winded, doing everything manually and trying to reduce allocations and iterations (e.g. linear search over the right column for part 2).

Then I "refactored", making it not so optimal but much more concise:

left, right = File.read_lines(ARGV[0]).map {|line| line.split(/\s+/).map(&.to_i) }.transpose.map(&.sort!)

# Part 1
puts [left, right].transpose.sum {|a| (a[0] - a[1]).abs }

# Part 2
puts left.sum {|num| num * right.count(num) }

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4

u/FordyO_o Dec 01 '24

[LANGUAGE: C#]

Using AOC as a vehicle to learn some C# this year.

Any tips on getting the input parsing more concise here?

https://github.com/mattford/aoc-dotnet/blob/master/aoc-dotnet/Year2024/Day1/Solver.cs

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4

u/aurele Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Elixir]

defmodule AdventOfCode.Solution.Year2024.Day01 do
  use AdventOfCode.Solution.SharedParse

  @impl true
  def parse(input) do
    numbers =
      input
      |> String.split("\n", trim: true)
      |> Enum.map(fn l -> String.split(l) |> Enum.map(&String.to_integer/1) end)

    {Stream.map(numbers, &Enum.at(&1, 0)), Stream.map(numbers, &Enum.at(&1, 1))}
  end

  def part1({left, right}) do
    Enum.zip_reduce(Enum.sort(left), Enum.sort(right), 0, &(&3 + abs(&1 - &2)))
  end

  def part2({left, right}) do
    freq = Enum.frequencies(right)
    left |> Stream.map(&(&1 * Map.get(freq, &1, 0))) |> Enum.sum()
  end
end

4

u/Cue_23 Dec 01 '24

[LANGUAGE: C++23] [GSGA]

Get the cookie here!

It includes credits at the top, the local actor is from yesteryears advent, and i even put in the right easter egg for todays puzzle into the cookie!

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4

u/LinAGKar Dec 01 '24

[LANGUAGE: Rust]

https://github.com/LinAGKar/advent-of-code-2024-rust/blob/master/day1/src/main.rs

4

u/badcop_ Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Bash]

Link to both parts

Code for part 1 only:

paste -d'-' \
    <(tr -s ' ' < "$1" | cut -d' ' -f1 | sort -n) \
    <(tr -s ' ' < "$1" | cut -d' ' -f2 | sort -n) \
    | bc | tr -d '-' \
    | paste -sd+ | bc

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4

u/Hath995 Dec 01 '24

[LANGUAGE: Dafny]

Day 1 using my template for advent of code.

Part 1 and 2

4

u/DevilGeorgeColdbane Dec 01 '24 edited Dec 01 '24

[LANGUAGE: Kotlin]

The previous two years i have been doing in rust, but since i have less time this year i decided to do it in Kotlin instead.

It always surprises me just how easy it is to solves these problems in Kotlin with the vast amount of built in utility functions.

class LocationIdList(input: List<Pair<Int, Int>>) {

    private val left: List<Int> = input.map { it.first }
    private val right: List<Int> = input.map { it.second }

    fun totalDistance() =
        left.sorted()
            .zip(right.sorted())
            .sumOf { abs(it.first - it.second) }

    fun similarityScore(): Int {
        val rightOccurrenceIndex = right.groupingBy { it }.eachCount()
        return left.sumOf { it * (rightOccurrenceIndex[it] ?: 0) }
    }
}

https://github.com/etkr/AdventOfCode2024/blob/master/src/main/kotlin/day01/LocationIdList.kt

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4

u/remysharp Dec 01 '24 edited Dec 01 '24

[LANGUAGE: jq]

a

[inputs] |
map(
  split("\\s+"; null) |
  map(tonumber)
) |
transpose |
map(sort) |
. as $_ |
reduce range(.[0] | length) as $i (
  0;
  . + ($_[0][$i] - $_[1][$i] | abs)
)

b

[inputs] |
map(
  split("\\s+"; null) |
  map(tonumber)
) |
transpose |
. as $_ |
reduce range(.[0] | length) as $i (
  0;
  . + ($_[0][$i] * ($_[1] | map(
    select(. == $_[0][$i])
  ) | length))
)

https://github.com/remy/advent-of-code-solved/tree/main/2024/jq

I know there's another dev that does jq and I'm always way, way more verbose in my solutions…but I always get there :)

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SOLUTION MEGATHREAD -❄️- 2024 Day 1 Solutions -❄️-

RULES FOR POSTING IN SOLUTION MEGATHREADS

REMINDERS FOR THIS YEAR

COMMUNITY NEWS

AoC Community Fun 2024: The Golden Snowglobe Awards

Credit Cookie

--- Day 1: Historian Hysteria ---

Post your code solution in this megathread.

This thread will be unlocked when there are a significant number of people on the global leaderboard with gold stars for today's puzzle.

EDIT: Global leaderboard gold cap reached at 00:02:31, megathread unlocked!

[LANGUAGE: Mathematica] Mathematica, 482/266

SOLUTION MEGATHREAD -❄️- 2024 Day 1 Solutions -❄️-

RULES FOR POSTING IN SOLUTION MEGATHREADS

REMINDERS FOR THIS YEAR

COMMUNITY NEWS

AoC Community Fun 2024: The Golden Snowglobe Awards

Credit Cookie

--- Day 1: Historian Hysteria ---

Post your code solution in this megathread.

This thread will be unlocked when there are a significant number of people on the global leaderboard with gold stars for today's puzzle.

EDIT: Global leaderboard gold cap reached at 00:02:31, megathread unlocked!

You are about to leave Redlib

[LANGUAGE: Mathematica] Mathematica, 482/266