char[,] Step(char[,] board, NeighboursDelegate neighbours, int emptyCutoff)
{
var newBoard = (char[, ])board.Clone();
for (int i = 0; i < board.GetLength(0); ++i)
{
for (int j = 0; j < board.GetLength(1); ++j)
{
newBoard[i, j] = board[i, j] switch
{
'L' => neighbours(board, i, j).All(c => c is not '#')
? '#'
: 'L',
'#' => neighbours(board, i, j).Count(c => c is '#') >= emptyCutoff
? 'L'
: '#',
char c => c,
}
}
}
;
return(newBoard);
}
int Solve(char[,] input, NeighboursDelegate neighbours, int emptyCutoff) =>
LINQExtensions.DoWhile(
x => !LINQExtensions.MatrixEquals(x.Prev, x.Stepped),
x => (x.Stepped, Step(x.Stepped, neighbours, emptyCutoff)),
(Prev: input, Stepped: Step(input, neighbours, emptyCutoff)))