Day 3: Lobby

Megathread guidelines

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FAQ

  • janAkali@lemmy.sdf.org
    3·
    3 days 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