Advent of code 2019/23

Ajax Direct

class Computer extends Intcode
{
    public function run()
    {
        while ($this->output->count() < 3 && $this->next()) {}

        if ($this->stop) {
            return [null, null, null];
        }

        $output = (array) $this->output;
        $this->output = set([]);
        return $output;
    }

    public function getInput()
    {
        if ($this->input->empty()) {
            $this->stop = true;
            return -1;
        }
        return $this->input->shift();
    }
}

// ==================================================
// > RUN
// ==================================================
$computers = set(range(0, 49))->map(fn ($i) => (new Computer($input, [$i])));

$nat = $last_nat = [];

while (true) {

    $idle = 0;

    foreach ($computers as $computer) {
        [$addr, $x, $y] = $computer->run();

        if (is_null($addr)) {
            $idle++;
            continue;
        }

        if ($addr == 255) {
            $nat = [$x, $y];
            if (empty($solution_1)) $solution_1 = $nat[1];
        } else {
            $computers[$addr]->input = $computers[$addr]->input->merge([$x, $y]);
        }
    }

    if ($idle >= 50 && !empty($nat)) {
        if ($nat[1] === ($last_nat[1]??false)) {
            $solution_2 = $nat[1];
            break;
        }

        $computers[0]->input = $computers[0]->input->merge($nat);
        $last_nat = $nat;
    }
}