Sudoku: Difference between revisions

Line 1,839:

[MethodImpl(MethodImplOptions.AggressiveInlining)]

private static int RowCol(int rc) => rc <= 2 ? 0 : rc <= 5 ? 3 : 6;

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private static IEnumerable<int> GetBox(int[][] grid, int row, int col) =>

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from r in Range(RowCol(row), 3)

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from c in Range(RowCol(col), 3)

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select grid[r][c];

private static ~~IEnumerable<(int~~ r,int ~~c)>~~ ~~GetBoxIndices~~(~~int row~~, ~~int col~~) =>

private static readonly int[] range = Range(1, 9).ToArray();

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from r in Range(RowCol(row), 3)

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from c in Range(RowCol(col), 3)

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select (r,c);

private static readonly Dictionary<(int r, int c), List<(int r, int c)>> Boxes =

(from row in Range(0, 3).Select(i => i * 3)

from col in Range(0, 3).Select(i => i * 3)

select ((row, col), GetBoxIndices(row, col)))

.ToDictionary(kvp => kvp.Item1, kvp => kvp.Item2.ToList());

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private static IEnumerable<int> GetBox(~~this~~ int[][] grid, int row, int col) =>

Boxes[(RowCol(row), RowCol(col))].Select(p=>grid[p.r][p.c]);

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private static readonly int[] ~~Domain~~ = Range(1, 9).ToArray();

private static bool Solve(this int[][] grid, List<(int, int)> cells, int idx) {

if (idx == 81)

Line 1,861:

Line 1,850:

var (r, c) = cells[idx];

foreach (var i in ~~Domain~~.Except(grid.Hints(r,c))) {

foreach (var i in range.Except(grid.Hints(r,c))) {

grid[r][c] = i;

if (grid.Solve(cells, idx + 1))

Line 1,871:

Line 1,860:

private static readonly int[] Unmarked = new[] { 0 };

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private static readonly int[] domain = Range(0, 9).ToArray();

private static IEnumerable<int> Hints(this int[][] grid, int row, int col) =>

grid[row]

.Union(~~Range(0, 9)~~.Select(r => grid[r][col]))

.Union(domain.Select(r => grid[r][col]))

.Union(~~grid.~~GetBox(row, col))

.Union(GetBox(grid, row, col))

.Except(Unmarked);

private static IEnumerable<(int, int)> SortedCells(this int[][] grid) =>

from row in ~~Range(0,9)~~

from row in domain

from col in ~~Range(0,9)~~

from col in domain

let cell = (count: grid[row][col] > 0 ? 10 : Hints(grid, row, col).Count(), cell: (row, col))

orderby cell.count descending