1 {-# LANGUAGE OverloadedStrings #-}
4 import qualified Data.Map.Strict as M
5 import Data.Map.Strict ((!))
6 -- import qualified Data.Set as S
7 -- import Data.Function (on)
8 import Data.Ord (comparing)
10 type Coord = (Integer, Integer) -- x, y
11 type Grid = M.Map Coord Integer
23 part1 grid = keyOfMaxValue sg
24 where sg = allSubCellPower 3 grid
27 part2 grid = maximumBy (comparing snd) $ [bestInGrid size grid | size <- [3..300]]
29 -- bestSubCell size grid =
31 makeGrid :: Integer -> Grid
32 makeGrid key = M.fromList [((x, y), powerLevel x y key) | x <- [1..300], y <- [1..300] ]
34 powerLevel :: Integer -> Integer -> Integer -> Integer
35 powerLevel x y key = ((interim `div` 100) `mod` 10) - 5
37 interim = ((rackID) * y + key) * rackID
39 subCellPower :: Integer -> Integer -> Integer -> Grid -> Integer
40 subCellPower size x y grid = sum [grid!(sx, sy) | sx <- [x..(x+size-1)], sy <- [y..(y+size-1)]]
42 allSubCellPower :: Integer -> Grid -> Grid
43 allSubCellPower size grid = M.fromList [((x, y), subCellPower size x y grid)| x <- [1..(301-size)], y <- [1..(301-size)]]
46 keyAndMaxValue :: Ord b => M.Map a b -> (a, b)
47 keyAndMaxValue m = M.foldrWithKey mergeKV (M.findMin m) m
48 where mergeKV k v (bestK, bestV) =
49 if v > bestV then (k, v) else (bestK, bestV)
51 keyOfMaxValue :: Ord b => M.Map a b -> a
52 keyOfMaxValue m = fst $ keyAndMaxValue m
54 bestInGrid :: Integer -> Grid -> ((Integer, Integer, Integer), Integer)
55 bestInGrid size grid = ((x, y, size), p)
56 where ((x, y), p) = keyAndMaxValue $ allSubCellPower size grid