bfsComponentSize.php

<?php
function bfsComponentSize($matrix) {
	$visited = [];
	$queue = [];
	$componentSize = 0;
	for ($i = 0; $i < count($matrix); $i++) {
		$visited[] = false;
	}
	$visited[1] = true;
	$queue[] = 1;
	while (count($queue) > 0) {
		$currentVertex = array_shift($queue);
		$visited[$currentVertex] = true;
		$componentSize++;
		for ($nextVertex = 0; $nextVertex < count($matrix); $nextVertex++) {
			if ($matrix[$currentVertex][$nextVertex] && !$visited[$nextVertex]) {
				$visited[$nextVertex] = true;
				$queue[] = $nextVertex;
			}
		}
	}
	return $componentSize;
}

$tab = [
	[true, false, false],
	[true, false, false],
	[false, false, false]
];
echo bfsComponentSize($tab);