PHP
PHP Code:
<?php
$input = <<<LOL
20,12,2,3,42,23,50
32,42,22,3,40,23,4
21,32,2,3,42,41,23
25,2,2,3,42,32,52
LOL;
$input = str_replace("\n", ",", $input);
$input = explode(",", $input);
$input = array_map('intval', $input);
$numbers = [];
foreach($input as $item) {
if ( ! isset($numbers[$item]) )
$numbers[$item] = 0;
$numbers[$item]++;
}
$common = [];
while ( count($numbers) > 0 ) {
foreach($numbers as $key => $number) {
$max_val = $number;
$max_id = $key;
break;
}
foreach ($numbers as $key => $number) {
if ( $number > $max_val ) {
$max_val = $number;
$max_id = $key;
}
}
$common[] = $max_id;
unset($numbers[$max_id]);
}
var_dump($common);