sudoku.hs

module Sudoku where

import Data.List (length, nub)
import Data.Matrix (Matrix, fromLists, safeSet, getRow, getCol)
import Data.Vector (Vector, filter, uniq)

type Board = Matrix (Maybe Int)
type Coord = (Int, Int)

validateVector :: Vector (Maybe Int) -> Bool
validateVector xs =
  length (uniq (xsNoNothing)) == length xsNoNothing
  where
    xsNoNothing = Data.Vector.filter (/= Nothing) xs

setCoord :: Board -> Coord -> Int -> Maybe Board
setCoord board (x,y) val =
  safeSet (Just val) (x,y) board

checkCoord :: Board -> Coord -> Bool
checkCoord board (x,y) =
 all (==True) [
    validateVector $ getRow x board
  , validateVector $ getCol y board
 ]