Advent of code 2022/17

Ajax Direct

function get_grid($input, $length)
{
    $grid = grid("-------", 1);

    $pieces = [
        grid("####", 1),
        grid(" # \n###\n # ")->filter(),
        grid("  #\n  #\n###")->filter(),
        grid("#\n#\n#\n#"),
        grid("##\n##")
    ];

    $chars = $input->chars;

    $bottom = 0;
    for ($i = 0; $i < $length; $i++) {
        $piece  = $pieces[$i % 5];
        $xy     = xy([2, $bottom -3 - $piece->height()]);
        $m      = 0;

        while (true) {
            $m++;

            if ($m % 2) {
                $move = $chars->shift();
                $chars[] = $move;

                // Move Left or Right
                if ($move == "<") {
                    if ($xy->x - 1 >= 0) {
                        $xy->move([-1, 0]);
                    }
                } else {
                    if ($xy->x + $piece->width() + 1 <= 7) {
                        $xy->move([1, 0]);
                    }
                }
            } else {
                // Move down
                $move = "v";
                $xy->move([0, 1]);
            }

            // Bottom reached
            if ($xy->y + $piece->height >= $bottom) {
                if ($grid->hasCollision((clone $piece)->move($xy))) {
                    $xy->back();
                    if (!($m % 2)) {
                        $grid->insert($xy, $piece);
                        $bottom = min($bottom, $xy->y);
                        break;
                    }
                }
            }
        }
    }

    return $grid;
}

// ==================================================
// > PART 1 > Takes 15s
// ==================================================
// $solution_1 = get_grid($input, 2022)->rows()->keys()->min();
$solution_1 = 3200;

// ==================================================
// > PART 2 > Done manually transforming the grid and searching for a pattern
// ==================================================
function row_char($row) {
    return chr(($row->keys()->reduce((fn ($id, $x) => $id + (2 ** $x)), 0)) + 92);
}

// Pattern starts at -493 : 317 stones
// Pattern ends at -3227 : 2042 stones
// => Pattern takes 1725 stones and add 2734 levels each time
// => Pattern should be repeated 579710144 times, leaving 1600 stones to check manually
// => 1584927533696 + 2551 = 1584927536247

$solution_2 = 1584927536247;