1
|
|
|
<?php declare(strict_types=1); |
2
|
|
|
|
3
|
|
|
namespace Stratadox\PuzzleSolver\Puzzle\Sudoku; |
4
|
|
|
|
5
|
|
|
use Stratadox\PuzzleSolver\Moves; |
6
|
|
|
use function assert; |
7
|
|
|
|
8
|
|
|
final class Sudoku |
9
|
|
|
{ |
10
|
|
|
/** @var int[][]|null[][] */ |
11
|
|
|
private $numbers; |
12
|
|
|
/** @var bool[][] */ |
13
|
|
|
private $rows = []; |
14
|
|
|
/** @var bool[][] */ |
15
|
|
|
private $cols = []; |
16
|
|
|
/** @var bool[][][] */ |
17
|
|
|
private $boxes = []; |
18
|
|
|
/** @var int[]|null */ |
19
|
|
|
private $firstEmptyPosition; |
20
|
|
|
|
21
|
|
|
public function __construct(array ...$numbers) |
22
|
|
|
{ |
23
|
|
|
$this->numbers = $numbers; |
24
|
|
|
foreach ($numbers as $r => $row) { |
25
|
|
|
foreach ($row as $c => $number) { |
26
|
|
|
if (null !== $number) { |
27
|
|
|
$this->rows[$r][$number] = true; |
28
|
|
|
$this->cols[$c][$number] = true; |
29
|
|
|
$this->boxes[$r / 3][$c / 3][$number] = true; |
30
|
|
|
} elseif (null === $this->firstEmptyPosition) { |
31
|
|
|
$this->firstEmptyPosition = [$r, $c]; |
32
|
|
|
} |
33
|
|
|
} |
34
|
|
|
} |
35
|
|
|
} |
36
|
|
|
|
37
|
|
|
public function isFull(): bool |
38
|
|
|
{ |
39
|
|
|
return null === $this->firstEmptyPosition; |
40
|
|
|
} |
41
|
|
|
|
42
|
|
|
public function possibilitiesForNextEmptyPosition(): Moves |
43
|
|
|
{ |
44
|
|
|
if (null === $this->firstEmptyPosition) { |
45
|
|
|
return Moves::none(); |
46
|
|
|
} |
47
|
|
|
[$r, $c] = $this->firstEmptyPosition; |
48
|
|
|
return Entry::allPossibilitiesFor($r, $c)->filterWith(function (Entry $entry) { |
|
|
|
|
49
|
|
|
return $this->allows($entry); |
50
|
|
|
}); |
51
|
|
|
} |
52
|
|
|
|
53
|
|
|
// For immutable sudoku puzzle implementations |
54
|
|
|
public function withFilledIn(Entry ...$entries): self |
55
|
|
|
{ |
56
|
|
|
$numbers = $this->numbers; |
57
|
|
|
foreach ($entries as $entry) { |
58
|
|
|
assert($this->allows($entry)); |
59
|
|
|
$numbers[$entry->row()][$entry->column()] = $entry->number(); |
60
|
|
|
} |
61
|
|
|
return new self(...$numbers); |
62
|
|
|
} |
63
|
|
|
|
64
|
|
|
public function __toString(): string |
65
|
|
|
{ |
66
|
|
|
$sudoku = "\n+-------+-------+-------+ \n"; |
67
|
|
|
foreach ($this->numbers as $r => $row) { |
68
|
|
|
$sudoku .= '| '; |
69
|
|
|
foreach ($row as $c => $value) { |
70
|
|
|
$sudoku .= ($value ?: ' ') . ' '; |
71
|
|
|
if ($c % 3 === 2) { |
72
|
|
|
$sudoku .= '| '; |
73
|
|
|
} |
74
|
|
|
} |
75
|
|
|
$sudoku .= "\n"; |
76
|
|
|
if ($r % 3 === 2) { |
77
|
|
|
$sudoku .= "+-------+-------+-------+ \n"; |
78
|
|
|
} |
79
|
|
|
} |
80
|
|
|
return $sudoku; |
81
|
|
|
} |
82
|
|
|
|
83
|
|
|
private function allows(Entry $entry): bool |
84
|
|
|
{ |
85
|
|
|
return null === $this->numbers[$entry->row()][$entry->column()] |
86
|
|
|
&& $this->canAddInRow($entry->row(), $entry->number()) |
87
|
|
|
&& $this->canAddInColumn($entry->column(), $entry->number()) |
88
|
|
|
&& $this->canAddInRegion($entry->row(), $entry->column(), $entry->number()); |
89
|
|
|
} |
90
|
|
|
|
91
|
|
|
private function canAddInRow(int $row, int $number): bool |
92
|
|
|
{ |
93
|
|
|
return !isset($this->rows[$row][$number]); |
94
|
|
|
} |
95
|
|
|
|
96
|
|
|
private function canAddInColumn(int $column, int $number): bool |
97
|
|
|
{ |
98
|
|
|
return !isset($this->cols[$column][$number]); |
99
|
|
|
} |
100
|
|
|
|
101
|
|
|
private function canAddInRegion(int $row, int $column, int $number): bool |
102
|
|
|
{ |
103
|
|
|
return !isset($this->boxes[$row / 3][$column / 3][$number]); |
104
|
|
|
} |
105
|
|
|
} |
106
|
|
|
|