$max = 400000;
$temp = explode(' ','A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0 1 2 3 4 5 6 7 8 9');
$data = array();
$n = 0;
while ( $n<$max )
{
shuffle($temp);
$code = implode('',array_slice($temp,0,4)).'-'.implode('',array_slice($temp,4,4)).'-'.implode('',array_slice($temp,8,4)).'-'.implode('',array_slice($temp,12,4));
if ( isset($data[$code]) ) continue;
$data[$code] = true;
$n++;
}
$keys = array_keys($data); unset($data);
for($i=0;$i<$for;$i++) {
$str = strtoupper(md5($i));
$string[$i] = substr($str,0,4)."-".substr($str,5,4)."-"."-".substr($str,9,4)."-"."-".substr($str,13,4);
}