CS代考程序代写 {-

{-
Module: Board.

Checks involving the board and machinery for “placing a wall”.
-}
module Board where

import Data.Graph
import Data.List
import Data.Array

import Types
import Cell
import Action

{-
Checking if a step is valid and using it to get the reachable cells from a given cell.
-}

— Check if step is contained in the board, i.e. is one of the edges.
validStep :: Board -> Step -> Bool
validStep b mv = (stepToEdge mv) `elem` (edges b)

— Cells reachable from a given cell.
reachableCells :: Board -> Cell -> [Cell]
reachableCells b c = filter (c’ -> validStep b (c, c’)) (cellsAroundInBoard c)

{-
Checking if a wall is valid.
-}

— Check if the steps representing the wall are parallel.
parallelSteps :: Board -> Step -> Step -> Bool
parallelSteps b (cs, ce) (cs’, ce’) =
((isHorizontallyAdjacent cs cs’) && (isHorizontallyAdjacent ce ce’) &&
(isVerticallyAdjacent cs ce) && (isVerticallyAdjacent cs’ ce’)) ||
((isVerticallyAdjacent cs cs’) && (isVerticallyAdjacent ce ce’) &&
(isHorizontallyAdjacent cs ce) && (isHorizontallyAdjacent cs’ ce’))

— Check that no wall has been placed that could interfere with the wall we want to place.
noCrossingWalls :: Board -> Step -> Step -> Bool
noCrossingWalls b (cs, ce) (cs’, ce’) = (validStep b (cs, cs’)) && (validStep b (ce, ce’))

— Check if the edges corresponding to the wall we want to remove are in the board.
validWallSteps :: Board -> Wall -> Bool
validWallSteps b (s, s’) = (validStep b s) && (validStep b s’)

— If the three conditions above are satisfied, it is a valid wall.
validWall :: Board -> Wall -> Bool
validWall b w@(s, s’) =
(validWallSteps b w) && (parallelSteps b s s’) && (noCrossingWalls b s s’)

{-
Action of placing a wall.
-}

— Remove a step (used for placing walls).
removeStep :: Board -> Step -> Board
removeStep b s =
let (cI, cI’) = stepToEdge s in
b//[(cI, delete cI’ (b!cI)), (cI’, delete cI (b!cI’))]

— Placing a wall is the same as removing the two steps that represent it.
placeWall :: Board -> Wall -> Board
placeWall b (mv, mv’) = removeStep (removeStep b mv) mv’