Złożoność obliczeniowa algorytmu

$dane = Array
(
    [0] => 130
    [1] => 4
    [2] => 12
    [3] => 32
    [4] => 40
    [5] => 3
    [6] => 14
    [7] => 19
    [8] => 27
    [9] => 25
    [10] => 31
    [11] => 49
    [12] => 51
    [13] => 55
    [14] => 50
    [15] => 100
)

$n = count($dane);
for($i = $n - 1; $i > 0; $i--) {
  for($j = 0; $j < $i; $j++) {
    if($dane[$j] > $dane[$j + 1]) {
      $tmp = $dane[$j];
      $dane[$j] = $dane[$j + 1];
      $dane[$j + 1] = $tmp;
    }
  }
}
echo "Posortowana tablica:";
echo "<pre>$dane = ";
print_r($dane);
echo "</pre><hr>";
Posortowana tablica:

Warning:  Array to string conversion in /var/www/vhosts/rychlicki.edu.pl/httpdocs/myphp/_algorytmy/index.php(33) : eval()'d code on line 12

Array = Array
(
    [0] => 3
    [1] => 4
    [2] => 12
    [3] => 14
    [4] => 19
    [5] => 25
    [6] => 27
    [7] => 31
    [8] => 32
    [9] => 40
    [10] => 49
    [11] => 50
    [12] => 51
    [13] => 55
    [14] => 100
    [15] => 130
)
Złożoność obliczeniowa algorytmu O(n²).