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<?php |
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namespace BlackScorp\Astar; |
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use BlackScorp\Astar\Heuristic\Manhattan; |
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class Astar |
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{ |
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private $diagonal = false; |
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private $blocked = array(); |
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/** |
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* @var HeuristicInterface |
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*/ |
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private $heuristic = null; |
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private $grid = null; |
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public function blocked(array $types) |
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{ |
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$this->blocked = $types; |
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} |
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public function enableDiagonal() |
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{ |
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$this->diagonal = true; |
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} |
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public function __construct(Grid $grid) |
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{ |
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$this->grid = $grid; |
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} |
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public function setHeuristic(HeuristicInterface $heuristic) |
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{ |
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$this->heuristic = $heuristic; |
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} |
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public function search(Node $start, Node $end) |
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{ |
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if (!$this->heuristic) { |
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$this->setHeuristic(new Manhattan()); |
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} |
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$heap = new ScoreHeap(); |
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$heap->insert($start); |
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$current = $this->fillHeap($heap, $start, $end); |
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if ($current !== $end) { |
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return []; |
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} |
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return $this->getReversedPath($current); |
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} |
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/** |
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* @param Node $end |
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* @param $heap |
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* @param $current |
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* @return Node |
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*/ |
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private function fillHeap(\SplHeap $heap, Node $current, Node $end) |
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{ |
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while ($heap->valid() && $current !== $end) { |
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/** |
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* @var Node $current |
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*/ |
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$current = $heap->extract(); |
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$current->close(); |
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$neighbors = $this->grid->getNeighbors($current, $this->diagonal); |
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foreach ($neighbors as $neighbor) { |
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if ($neighbor->isClosed() || in_array($neighbor->getCosts(), $this->blocked)) { |
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continue; |
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} |
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$score = $current->getScore() + $neighbor->getCosts(); |
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$visited = $neighbor->isVisited(); |
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if (!$visited || $score < $neighbor->getScore()) { |
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$neighbor->visit(); |
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$neighbor->setParent($current); |
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$neighbor->setGuessedScore($this->heuristic->compare($neighbor, $end)); |
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$neighbor->setScore($score); |
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$neighbor->setTotalScore($neighbor->getScore() + $neighbor->getGuessedScore()); |
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if (!$visited) { |
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$heap->insert($neighbor); |
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} |
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} |
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} |
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} |
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return $current; |
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} |
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/** |
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* @param Node $current |
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* @return array |
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*/ |
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private function getReversedPath(Node $current) |
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{ |
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$result = []; |
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while ($current->getParent()) { |
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$result[] = $current; |
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$current = $current->getParent(); |
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} |
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return array_reverse($result); |
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} |
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} |
BlackScorp /
astar
