11/one.icl

   1 module one
   2
   3 import StdEnv
   4 import Data.Func
   5
   6 import Text
   7
   8 read :: *File -> [String]
   9 read f
  10         # (l, f) = freadline f
  11         | l.[size l - 1] <> '\n' = []
  12         = [l % (0, size l - 2):read f]
  13
  14 Start w
  15         # (io, w) = stdio w
  16         # ls = read io
  17         # ls = {l\\l<-ls}
  18         = one ls
  19
  20 instance == {#String} where
  21         (==) l r = and [l==r\\l<-:l & r<-:r]
  22
  23 one :: {#String} -> Int
  24 one ls = length [()\\r<-:cell ls, c<-:r | c == '#']
  25
  26 cell :: !{#String} -> {#String}
  27 cell ls = let ls` = step ls in if (ls` == ls) ls (cell ls`)
  28
  29 step :: !{#String} -> {#String}
  30 step ls = {{step` x y\\x<-[0..size ls.[0] - 1]}\\y<-[0..size ls - 1]}
  31 where
  32         step` :: Int Int -> Char
  33         step` x y = case ls.[y,x] of
  34                 '.' = '.'
  35                 'L' = if (occupied == 0) '#' 'L'
  36                 '#' = if (occupied >= 4) 'L' '#'
  37         where
  38                 occupied = length [()\\dx<-[-1..1], dy<-[-1..1] | not (dx == 0 && dy == 0) && not (empty (x+dx) (y+dy))]
  39         empty :: Int Int -> Bool
  40         empty x y
  41                 | x < 0 || x >= size ls.[0] || y < 0 || y >= size ls = True
  42                 = ls.[y,x] <> '#'