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run code in 150+ php & hhvm versions
Bugs & Features
<?php function count_and_find($arr) { sort($arr); $missing = array(); $index = 0; $count = count($arr); while ($num = array_shift($arr)) { do { if ($index < $num) { $missing[] = $index; $index++; } } while ($index < $num); } return array('missing' => $missing, 'total' => $count); } var_dump(count_and_find(array(1,6,2,9,3,0,5,7,4)));
based on duKri
Output for 4.3.0 - 7.1.0
array(2) { ["missing"]=> array(0) { } ["total"]=> int(9) }