// Method establishes which values can fill an empty square by eliminating any values already occurring in row/column/box. public List<int> DetermineValidOptionsForSquare(SquareCoordinate squareCoordinate, IImmutableSudokuGrid grid) { HashSet<int> validSquareOptions = new HashSet<int> { 1, 2, 3, 4, 5, 6, 7, 8, 9 }; for (int offset = 1; offset < 9; offset++) { validSquareOptions.Remove(grid.Elements[(squareCoordinate.Row + offset) % 9, squareCoordinate.Column]); validSquareOptions.Remove(grid.Elements[(squareCoordinate.Row), (squareCoordinate.Column + offset) % 9]); validSquareOptions.Remove(grid.Elements[(3 * (squareCoordinate.Row / 3)) + offset % 3, (3 * (squareCoordinate.Column / 3)) + (offset - offset % 3) / 3]); } return validSquareOptions.ToList<int>(); }
// Method establishes which values can fill an empty square by eliminating any values already occurring in row/column/box. public List <int> DetermineValidOptionsForSquare(SquareCoordinate squareCoordinate, IImmutableSudokuGrid grid) { HashSet <int> validSquareOptions = new HashSet <int> { 1, 2, 3, 4, 5, 6, 7, 8, 9 }; for (int offset = 1; offset < 9; offset++) { validSquareOptions.Remove(grid.Elements[(squareCoordinate.Row + offset) % 9, squareCoordinate.Column]); validSquareOptions.Remove(grid.Elements[(squareCoordinate.Row), (squareCoordinate.Column + offset) % 9]); validSquareOptions.Remove(grid.Elements[(3 * (squareCoordinate.Row / 3)) + offset % 3, (3 * (squareCoordinate.Column / 3)) + (offset - offset % 3) / 3]); } return(validSquareOptions.ToList <int>()); }