- substr: documentation ( source)
- strrev: documentation ( source)
<?php
$string1 = 'abcdefghijklmonpqrst';
for($i = 1; $i <= 200000; $i++)
{
$x=$i * 5;
$x=$x + $x;
$x=$x/10;
$string3 = $string1 . strrev($string1);
$string2 = substr($string1, 9, 1) . substr($string1, 0, 9);
$string1 = $string2;
}
?>