Find the nearest clone

Shortest HackerRank.php

<?php

class Node {

	public $id;
	public $edges = [];
	public $colorId;

	public function __construct( $id, $colorId ) {
		$this->id      = $id;
		$this->colorId = $colorId;
	}

	public function setEdge( Node $edge ) {
		$this->edges[] = $edge;
	}
}

function findShortest( $graph_nodes, $graph_from, $graph_to, $ids, $val ) {
	$nodes = [];
	$start = null;

	for ( $i = 1; $i <= $graph_nodes; $i ++ ) {
		$colorId     = $ids[ $i - 1 ];
		$nodes[ $i ] = new Node( $i, $colorId );

		if ( ! $start && $colorId === $val ) {
			$start = $nodes[ $i ];
		}
	}

	if ( ! $start ) {
		return -1;
	}

	foreach ( $graph_from as $key => $nodeFrom ) {
		$nodeSource = $nodes[ $nodeFrom ];
		$nodeTarget = $nodes[ $graph_to[ $key ] ];
		$nodeSource->setEdge( $nodeTarget );
		$nodeTarget->setEdge( $nodeSource );
	}

	$queue                      = [ $start, null ];
	$currentNode                = $start;
	$visitedNodes               = [ $start->id => $start ];
	$levels[ $currentNode->id ] = 0;

	while ( $queue ) {

		foreach ( $currentNode->edges as $edge ) {

			if ( isset( $visitedNodes[ $edge->id ] ) ) {
				continue;
			}

			$visitedNodes[ $edge->id ] = $edge;
			$currentLevel              = $levels[ $currentNode->id ] + 1;

			if ( $edge->colorId === $val ) {
				return $currentLevel;
			}

			$levels[ $edge->id ] = $currentLevel;
			$queue[]             = $edge;
		}

		array_shift( $queue );
		$visitedNodes[ $currentNode->id ] = $currentNode;
		$currentNode                      = current( $queue );
	}

	return - 1;
}

$graph_nodes = 4;
$graph_from  = [ 1, 1, 4 ];
$graph_to    = [ 2, 3, 2 ];
$ids         = [ 1, 2, 1, 1 ];
$val         = 6;

findShortest( $graph_nodes, $graph_from, $graph_to, $ids, $val );