Advent of code 2022/11

Ajax Direct

class Monkey
{
    function __construct($monkey)
    {
        preg_match("/Starting items\: ?([^\n]+)/", $monkey->string, $items);
        $this->items = set(explode(", ", $items[1]));

        preg_match("/new = old ([^\n]+)/", $monkey->string, $op);
        $this->op = explode(" ", $op[1]);

        preg_match("/divisible by ([0-9]+)/", $monkey->string, $test);
        $this->test = (int) $test[1];

        preg_match_all("/throw to monkey ([0-9]+)/", $monkey->string, $pass);
        $this->pass = $pass[1];

        $this->inspected = 0;
    }

    function inspect($monkeys, $divider, $reductor)
    {
        global $ops;
        $worry = $this->items->shift();
        $this->inspected++;

        $worry = ($this->op[0] == "+" ? $worry + $this->op[1] : (
            $this->op[1] == "old" ? ($worry * $worry) : ($worry * $this->op[1])
        ));

        $worry = floor($worry / $divider);
        $worry = $worry % $reductor; // Avoid numbers too large while keeping testing integrity

        $next                    = $worry % $this->test ? $this->pass[1] : $this->pass[0];
        $monkeys[$next]->items[] = $worry;
    }
}


function get_solution($input, $rounds, $divider)
{
    $monkeys = $input->split("\n\n")->map(fn($monkey) => new Monkey($monkey));
    $reductor = $monkeys->column("test")->multiply();

    for ($i = 0; $i < $rounds; $i++) {
        foreach ($monkeys as $monkey) {
            while ($monkey->items->count()) {
                $monkey->inspect($monkeys, $divider, $reductor);
            }
        }
    }

    return $monkeys->column("inspected")->sort()->slice(-2)->multiply();
}

// ==================================================
// > SOLUTIONS
// ==================================================
$solution_1 = get_solution($input, 20, 3);
$solution_2 = get_solution($input, 10000, 1);