12/two.icl

   1 module two
   2
   3 import StdEnv
   4 import Data.Func
   5 import Data.Tuple
   6
   7 read :: *File -> [(Char, Int)]
   8 read f
   9         # (l, f) = freadline f
  10         | l.[size l - 1] <> '\n' = []
  11         = [(l.[0], toInt (l % (1, size l - 2))):read f]
  12
  13 Start w
  14         # (io, w) = stdio w
  15         # ls = read io
  16         = (\s->abs s.sx+abs s.sy)
  17         $ foldl move {sx=0,sy=0,wx=10,wy=1} ls
  18
  19 :: Ship = { sx :: Int, sy :: Int, wx :: Int, wy :: Int }
  20
  21 move s ('N', n) = {s & wy=s.wy+n}
  22 move s ('S', n) = {s & wy=s.wy-n}
  23 move s ('E', n) = {s & wx=s.wx+n}
  24 move s ('W', n) = {s & wx=s.wx-n}
  25 move s ('F', n)
  26         # dx = s.wx-s.sx
  27         # dy = s.wy-s.sy
  28         # s = {s & sx=s.sx+dx*n, sy=s.sy+dy*n}
  29         = {s & wx=s.sx+dx, wy=s.sy+dy}
  30 move s ('R', n) = rot (n/90) s
  31 move s ('L', n) = rot (3*(n/90)) s
  32
  33 //https://stackoverflow.com/questions/2259476/rotating-a-point-about-another-point-2d/25196651#25196651
  34 rot :: Int Ship -> Ship
  35 rot 0 ship = ship
  36 rot n ship=:{sx, sy, wx, wy}
  37         # s = toInt (sin 90.0)
  38         # c = toInt (cos 90.0)
  39         # nx = sx + ( (wx-sx) * c + (wy-sy) * s)
  40         # ny = sy + (~(wx-sx) * s + (wy-sy) * c)
  41         = rot (n-1) {ship & wx=nx, wy=ny}