d15p2

2022/day15/day15.hs

@@ -1,32 +1,24 @@
 import Control.Lens
-import Data.List
 import Data.List.Split
-import qualified Data.Map as M
 import Linear.V2
 
 type Sensor = (V2 Int, V2 Int)
 
-type Cave = M.Map (V2 Int) Char
-
 main :: IO ()
 main = do
   input <- map (splitOneOf "=,:") . lines <$> readFile "input"
   let sensors = map parse input
---  print $ "Cave from to: " ++ show (caveMinMaxX sensors)
---  print $ part1 (caveMinMaxX sensors) sensors
---  print $ getBorder sensors
---  print $ last [(x,x) | x<-[0..10000]]
---  print $ last [(x,y) | x<-[0..10000], y<-[0..10000], x==y]
-  print "hello world"
-
-
-allCandidates :: [Sensor] -> [Int] -> [V2 Int]
-allCandidates (s:ss) ds = undefined
+  print $ "Cave from to: " ++ show (caveMinMaxX sensors)
+  print $ part1 (caveMinMaxX sensors) sensors
+  print $ part2 sensors
 
 getBorder :: [Sensor] -> [V2 Int]
-getBorder (s:ss) = map (+ (fst s)) xs ++ getBorder ss
-    where xs = [V2 x (d - x) | x<-[-d..0]++[1..d]]
-          d = succ $ dist s
+getBorder (s:ss) = map (+ fst s) xs ++ getBorder ss
+  where
+    xs =
+      concat $ take 4 $ iterate (map perp) [V2 x (d - x) | x <- [0 .. pred d]]
+    d = succ $ dist s
+getBorder [] = []
 
 caveMinMaxX :: [Sensor] -> (Int, Int)
 caveMinMaxX sensors = (minimum k, maximum l)
@@ -41,6 +33,16 @@ part1 (a, b) sensors = length $ filter (== '#') $ map (checkPoint sensors) xs
   where
     xs = [V2 x 2000000 | x <- [a .. b]] --y=10 for testinput
 
+part2 :: [Sensor] -> Int
+part2 sensors =
+  f $
+  head $
+  filter (\x -> checkPoint sensors x == ' ') $
+  filter (\(V2 x y) -> x >= 0 && x <= 4000000 && y >= 0 && y <= 4000000) $
+  getBorder sensors -- <=20 for testinput
+  where
+    f = (+) <$> view _y <*> ((*) 4000000 . view _x)
+
 parse :: [String] -> Sensor
 parse [_, a, _, b, _, c, _, d] = (V2 (read a) (read b), V2 (read c) (read d))