Advent of code 2019/7

Ajax Direct

// ==================================================
// > PART 1
// ==================================================
$solution_1 = 0;
foreach (set(range(0, 4))->permutations() as $sequence) {
    $is = 0;
    foreach ($sequence as $ps) {
        $is = (new Intcode($input, [$ps, $is]))->run();
    }
    $solution_1 = max($is, $solution_1);
}

// ==================================================
// > PART 2
// ==================================================
$solution_2 = 0;

foreach (set(range(5, 9))->permutations() as $sequence) {
    $amb = set(range(0, 4))->map(fn ($i) => new Intcode($input, [array_values($sequence)[$i]]));
    $amb[0]->input[] = 0;

    while (true) {
        foreach (range(0, 4) as $m) {
            // Run until it stops or waits for an input
            // Add its last output to the next machine in the loop
            $amb[($m + 1) % 5]->input[] = $amb[$m]->run();
        }
        // Stop everything once the last machine is completely done
        if ($amb[4]->ended) break;
    }

    $solution_2 = max($solution_2, $amb[4]->output->last());
}