/**
* @param NodeInterface $goal
* @param NodeInterface $current
* @return number
*/
protected function getHeuristic(NodeInterface $goal, NodeInterface $current)
{
return abs($goal->getX() - $current->getX()) + abs($goal->getY() - $current->getY());
}
/**
* @param NodeInterface $node
* @return string
*/
protected function hash(NodeInterface $node)
{
return md5($node->getX() . "," . $node->getY());
}