Advent Of Code

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An unofficial home for the advent of code community on programming.dev! Other challenges are also welcome!

Advent of Code is an annual Advent calendar of small programming puzzles for a variety of skill sets and skill levels that can be solved in any programming language you like.

Everybody Codes is another collection of programming puzzles with seasonal events.

AoC 2025

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console.log('Hello World')

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💃 - 2025 DAY 3 SOLUTIONS - 💃 (programming.dev)

submitted 2 weeks ago by CameronDev@programming.dev to c/advent_of_code@programming.dev

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Day 3: Lobby

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What is this?: Here is a post with a large amount of details: https://programming.dev/post/6637268
Where do I participate?: https://adventofcode.com/
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[–] janAkali@lemmy.sdf.org 3 points 2 weeks ago

Nim

type
  AOCSolution[T,U] = tuple[part1: T, part2: U]

proc maxJoltage(bank: string, n: int): int =
  var index = 0
  for leftover in countDown(n-1, 0):
    var best = bank[index]
    for batteryInd in index+1 .. bank.high-leftover:
      let batt = bank[batteryInd]
      if batt > best: (best = batt; index = batteryInd)
      if best == '9': break # max for single battery
    result += (best.ord - '0'.ord) * 10^leftover
    inc index

proc solve(input: string): AOCSolution[int, int] =
  for line in input.splitLines:
    result.part1 += line.maxJoltage 2
    result.part2 += line.maxJoltage 12

Runtime: ~240 μs

Day 3 was very straightforward, although I did wrestle a bit with the indexing.
Honestly, I expected part 2 to require dynamic programming, but it turned out I only needed to tweak a few numbers in my part 1 code.

Full solution at Codeberg: solution.nim