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September 12, 2019 05:54
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PHP BFS on a Tree
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function BFS( $node, $data ) { | |
if ( $node->data == $data ) | |
return $node; | |
$node->visited = true; | |
$queue = new Queue; | |
$queue->enqueue($node); | |
while ( !$queue->isEmpty() ) { | |
$node = $queue->dequeue(); | |
if ( !$node->visited ) { | |
if ( $node->data == $data ) | |
return $node; | |
$node->visited = true; | |
} | |
if ( !is_null( $node->left ) ) | |
$queue->enqueue( $node->left ); | |
if ( !is_null( $node->right ) ) | |
$queue->enqueue( $node->right ); | |
} | |
} | |
class Queue { | |
protected $first; | |
protected $last; | |
public function enqueue($node) { | |
if ( is_null( $this->first ) ) { | |
$this->first = $this->last = $node; | |
} else { | |
$this->last->next = $node; | |
$this->last = $node; | |
} | |
} | |
public function dequeue() { | |
if ( is_null( $this->first ) ) | |
return $this->first; | |
$node = $this->first; | |
$this->first = $node->next; | |
return $node; | |
} | |
public function isEmpty() { | |
return is_null( $this->first ); | |
} | |
} | |
class Node { | |
public $data; | |
public $left; | |
public $right; | |
public $next; | |
public $visited = false; | |
public function __construct($data) { | |
$this->data = $data; | |
} | |
} |
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