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<?php |
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namespace Mado\QueryBundle\Component\Meta; |
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/** |
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* @since Class available since Release 2.1.0 |
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*/ |
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class Dijkstra |
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{ |
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private $map; |
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private $distance; |
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private $prev; |
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private $visited; |
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public function setMap($map) |
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{ |
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foreach ($map as $nodeName => $metaData) { |
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foreach ($metaData['relations'] as $itemKey => $itemValue) { |
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$this->map[$nodeName][$itemValue] = 1; |
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} |
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} |
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} |
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private function processQueue(array $excluded) |
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{ |
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$this->ensureMapIsDefined(); |
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$node = array_search(min($this->visited), $this->visited); |
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if (!empty($this->map[$node]) && !in_array($node, $excluded)) { |
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foreach ($this->map[$node] as $neighbor => $cost) { |
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if (isset($this->distance[$neighbor])) { |
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if ($this->distance[$node] + $cost < $this->distance[$neighbor]) { |
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$this->distance[$neighbor] = $this->distance[$node] + $cost; |
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$this->prev[$neighbor] = [$node]; |
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$this->visited[$neighbor] = $this->distance[$neighbor]; |
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} elseif ($this->distance[$node] + $cost === $this->distance[$neighbor]) { |
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$this->prev[$neighbor][] = $node; |
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$this->visited[$neighbor] = $this->distance[$neighbor]; |
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} |
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} |
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} |
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} |
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unset($this->visited[$node]); |
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} |
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private function extractPaths($target) |
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{ |
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$paths = [[$target]]; |
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while (current($paths) !== false) { |
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$key = key($paths); |
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$path = current($paths); |
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next($paths); |
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if (!empty($this->prev[$path[0]])) { |
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foreach ($this->prev[$path[0]] as $prev) { |
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$copy = $path; |
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array_unshift($copy, $prev); |
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$paths[] = $copy; |
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} |
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unset($paths[$key]); |
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} |
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} |
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return array_values($paths); |
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} |
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public function shortestPaths($source, $target, array $excluded = array()) |
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{ |
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$this->ensureMapIsDefined(); |
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$this->distance = array_fill_keys(array_keys($this->map), INF); |
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$this->distance[$source] = 0; |
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$this->prev = array_fill_keys(array_keys($this->map), []); |
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$this->visited = [$source => 0]; |
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while (!empty($this->visited)) { |
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$this->processQueue($excluded); |
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} |
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if ($source === $target) { |
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return [[$source]]; |
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} elseif (empty($this->prev[$target])) { |
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return []; |
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} |
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return $this->extractPaths($target); |
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} |
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public function ensureMapIsDefined() |
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{ |
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if (!$this->map) { |
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throw new \RuntimeException( |
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'Oops! Map is not defined' |
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); |
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} |
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} |
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} |
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studiomado /
query-bundle
