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<?php declare(strict_types=1); |
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namespace Stratadox\PuzzleSolver\Puzzle\SlidingPuzzle; |
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use RuntimeException; |
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use function array_fill; |
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use function array_map; |
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use function assert; |
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use function count; |
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use function implode; |
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use function range; |
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use function str_replace; |
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use const PHP_EOL; |
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final class Board |
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{ |
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/** @var int[][] */ |
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private $pieces; |
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/** @var int */ |
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private $openRow; |
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/** @var int */ |
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private $openCol; |
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/** @var int */ |
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private $height; |
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/** @var int */ |
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private $width; |
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public function __construct(array ...$pieces) |
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{ |
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$this->pieces = $pieces; |
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[$this->openRow, $this->openCol] = $this->findOpenSpace(...$pieces); |
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$this->height = count($pieces); |
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assert($this->height > 0); |
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$this->width = count($pieces[0]); |
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} |
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public function afterSliding(Slide ...$slides): self |
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{ |
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$pieces = $this->pieces; |
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foreach ($slides as $slide) { |
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$pieces = $slide->applyTo($pieces); |
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} |
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return new self(...$pieces); |
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} |
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public function isSolved(): bool |
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{ |
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return $this->goalState() === $this->currentState(); |
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} |
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public function currentState(): string |
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{ |
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return implode(array_map('implode', $this->pieces)); |
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} |
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public function goalState(): string |
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{ |
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return implode(range(1, $this->width * $this->height - 1)) . '0'; |
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} |
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/** @return Slide[] */ |
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public function possibleSlides(): array |
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{ |
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$slides = []; |
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if ($this->openRow < $this->height - 1) { |
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$slides[] = Slide::up($this->pieces, $this->openRow + 1, $this->openCol); |
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} |
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if ($this->openRow > 0) { |
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$slides[] = Slide::down($this->pieces, $this->openRow - 1, $this->openCol); |
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} |
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if ($this->openCol < $this->width - 1) { |
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$slides[] = Slide::left($this->pieces, $this->openRow, $this->openCol + 1); |
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} |
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if ($this->openCol > 0) { |
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$slides[] = Slide::right($this->pieces, $this->openRow, $this->openCol - 1); |
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} |
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return $slides; |
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} |
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public function __toString(): string |
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{ |
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return str_replace('0', ' ', implode(PHP_EOL, array_map( |
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'implode', |
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array_fill(0, $this->width, ', '), |
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$this->pieces |
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))) . ' '; |
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} |
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/** @return int[] */ |
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private function findOpenSpace(array ...$pieces): array |
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{ |
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foreach ($pieces as $r => $row) { |
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foreach ($row as $c => $value) { |
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if (0 === $value) { |
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return [$r, $c]; |
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} |
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} |
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} |
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throw new RuntimeException('No open space!'); |
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} |
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} |
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Stratadox /
PuzzleSolver
