From: Mart Lubbers <mart@martlubbers.net>
Date: Sat, 12 Dec 2020 08:44:33 +0000 (+0100)
Subject: buggy 2 with n 90degree instead of one rotation
X-Git-Url: https://git.martlubbers.net/?a=commitdiff_plain;h=754773056f0764224f62ab7757dfafb6828146d3;p=aoc20.git

buggy 2 with n 90degree instead of one rotation
---

diff --git a/12/two.icl b/12/two.icl
new file mode 100644
index 0000000..2078f63
--- /dev/null
+++ b/12/two.icl
@@ -0,0 +1,41 @@
+module two
+
+import StdEnv
+import Data.Func
+import Data.Tuple
+
+read :: *File -> [(Char, Int)]
+read f
+	# (l, f) = freadline f
+	| l.[size l - 1] <> '\n' = []
+	= [(l.[0], toInt (l % (1, size l - 2))):read f]
+
+Start w
+	# (io, w) = stdio w
+	# ls = read io
+	= (\s->abs s.sx+abs s.sy)
+	$ foldl move {sx=0,sy=0,wx=10,wy=1} ls
+
+:: Ship = { sx :: Int, sy :: Int, wx :: Int, wy :: Int }
+
+move s ('N', n) = {s & wy=s.wy+n}
+move s ('S', n) = {s & wy=s.wy-n}
+move s ('E', n) = {s & wx=s.wx+n}
+move s ('W', n) = {s & wx=s.wx-n}
+move s ('F', n)
+	# dx = s.wx-s.sx
+	# dy = s.wy-s.sy
+	# s = {s & sx=s.sx+dx*n, sy=s.sy+dy*n}
+	= {s & wx=s.sx+dx, wy=s.sy+dy}
+move s ('R', n) = rot (n/90) s
+move s ('L', n) = rot (3*(n/90)) s
+
+//https://stackoverflow.com/questions/2259476/rotating-a-point-about-another-point-2d/25196651#25196651
+rot :: Int Ship -> Ship
+rot 0 ship = ship
+rot n ship=:{sx, sy, wx, wy}
+	# s = toInt (sin 90.0)
+	# c = toInt (cos 90.0)
+	# nx = sx + ( (wx-sx) * c + (wy-sy) * s)
+	# ny = sy + (~(wx-sx) * s + (wy-sy) * c)
+	= rot (n-1) {ship & wx=nx, wy=ny}