Advent of code 2018/9

Ajax Direct

function solve($players_count, $last_marble) {
    $scores  = array_fill_keys(range(0, $players_count - 1), 0);
    $circle  = new LinkedList(0, true);
    $current = $circle->getHead();

    for ($marble = 1; $marble < $last_marble; $marble++) {
        $player = $marble % $players_count;

        if (!($marble % 23)) {
            for ($i = 0; $i < 7; $i++) $current = $current->getPrev();
            $scores[$player] += $marble + $current->getValue();
            $current->remove();
            $current = $current->getNext();
            continue;
        }

        $current = $current->getNext()->insertAfter($marble);
    }

    return max($scores);
}

// ==================================================
// > PART 1
// ==================================================
[$players_count, $last_marble] = $input->numbers();
$solution_1 = solve($players_count, $last_marble);

// ==================================================
// > PART 2
// ==================================================
$solution_2 = solve($players_count, $last_marble * 100);