Current File : /home/tjamichg/cursos.tjamich.gob.mx/vendor/graphp/algorithms/src/Bipartit.php
<?php
namespace Graphp\Algorithms;
use Fhaculty\Graph\Exception\UnexpectedValueException;
use Fhaculty\Graph\Graph;
class Bipartit extends BaseGraph
{
/**
* check whether this graph is bipartit
*
* @return bool
* @uses AlgorithmBipartit::getColors()
*/
public function isBipartit()
{
try {
$this->getColors();
return true;
} catch (UnexpectedValueException $ignore) { }
return false;
}
/**
* checks whether the input graph's vertex groups are a valid bipartition
*
* @return bool
* @uses AlgorithmGroups::isBipartit()
*/
public function isBipartitGroups()
{
$alg = new Groups($this->graph);
return $alg->isBipartit();
}
/**
* get map of vertex ID to vertex color
*
* @return int[]
* @throws UnexpectedValueException if graph is not bipartit
* @uses AlgorithmBipartit::checkVertex() for every vertex not already colored
*/
public function getColors()
{
$colors = array();
// get color for each vertex
foreach ($this->graph->getVertices()->getMap() as $vid => $startVertex) {
if (!isset($colors[$vid])) {
$queue = array($startVertex);
// initialize each components color
$colors[$vid] = 0;
// breadth search all vertices in same component
do {
// next vertex in color
$vertex = \array_shift($queue);
$color = $colors[$vertex->getId()];
$nextColor = 1-$color;
// scan all vertices connected to this vertex
foreach ($vertex->getVerticesEdge()->getMap() as $vid => $nextVertex) {
// color unknown, so expect next color for this vertex
if (!isset($colors[$vid])) {
$colors[$vid] = $nextColor;
$queue[] = $nextVertex;
// color is known but differs => can not be bipartit
} elseif ($colors[$vid] !== $nextColor) {
throw new UnexpectedValueException('Graph is not bipartit');
}
}
} while ($queue);
}
}
return $colors;
}
/**
* get groups of vertices per color
*
* @return array[] array of arrays of vertices
*/
public function getColorVertices()
{
$colors = $this->getColors();
$ret = array(0 => array(), 1 => array());
foreach ($this->graph->getVertices()->getMap() as $vid => $vertex) {
$ret[$colors[$vid]][$vid] = $vertex;
}
return $ret;
}
/**
* create new graph with valid groups set according to bipartition colors
*
* @return Graph
* @throws UnexpectedValueException if graph is not bipartit
* @uses AlgorithmBipartit::getColors()
* @uses Graph::createGraphClone()
* @uses Vertex::setGroup()
*/
public function createGraphGroups()
{
$colors = $this->getColors();
$graph = $this->graph->createGraphClone();
foreach ($graph->getVertices()->getMap() as $vid => $vertex) {
$vertex->setGroup($colors[$vid]);
}
return $graph;
}
}
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