Day 14: Restroom Redoubt

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)
  • You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://topaz.github.io/paste/ if you prefer sending it through a URL

FAQ

  • janAkali ( janAkali@lemmy.one ) English
    2·
    2 years ago

    Nim

    Part 1: there’s no need to simulate each step, final position for each robot is
    (position + velocity * iterations) modulo grid
    Part 2: I solved it interactively: Maybe I just got lucky, but my input has certain pattern: after 99th iteration every 101st iteration looking very different from other. I printed first couple hundred iterations, noticed a pattern and started looking only at “interesting” grids. It took 7371 iterations (I only had to check 72 manually) to reach an easter egg.

    type
  Vec2 = tuple[x,y: int]
  Robot = object
    pos, vel: Vec2

var
  GridRows = 101
  GridCols = 103

proc examine(robots: seq[Robot]) =
  for y in 0..