Day 15: Lens Library

Megathread guidelines

  • Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
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FAQ

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  • janAkali@lemmy.oneEnglish
    2·
    11 months ago

    Nim

    My whole solution can be expressed in just two words: Ordered HashTable

    Total runtime: 0.068 line-seconds (40 LOC * 1.7 ms)
    Puzzle rating: exceptionally confusing description 4/10
    Code: cleaned up solution with types
    Snippet:

    proc getHash(s: string): int =
  for c in s:
    result = ((result + c.ord) * 17) mod 256

proc solve(lines: seq[string]): AOCSolution[int] =
  var boxes: array[256, OrderedTable[string, int]]
  for line in lines:
    block p1:
      result.part1 += line.getHash()

    block p2:
      if line.endsWith('-'):
        var name = line.strip(leading=false, chars={'-'})
        boxes[getHash(name)].del(name)
      else:
        let (name, _, value) = line.partition("=")
        boxes[getHash(name)][name] = value[0].ord - '0'.ord

  for bi, box in boxes:
    if box.len < 1: continue
    for vi, val in enumerate(box.values):
      result.part2 += (bi+1) * (vi+1) * val