Hvordan finder jeg alle mulige bogstavkombinationer af givne bogstaver dog...

<?php

function permute($str) {
    /* If we only have a single character, return it */
    if (strlen($str) < 2) {
        return array($str);
    }

    /* Initialize the return value */
    $permutations = array();

    /* Copy the string except for the first character */
    $tail = substr($str, 1);

    /* Loop through the permutations of the substring created above */
    foreach (permute($tail) as $permutation) {
        /* Get the length of the current permutation */
        $length = strlen($permutation);

        /* Loop through the permutation and insert the first character of the original
        string between the two parts and store it in the result array */
        for ($i = 0; $i <= $length; $i++) {
            $permutations[] = substr($permutation, 0, $i) . $str[0] . substr($permutation, $i);
        }
    }

    /* Return the result */
    return $permutations;
}

$str="aabcd";
$length_perm = 4; //Antal bogstaver der skal bruges
$permutations = array_unique(permute($str));
foreach($permutations as $word) {
$permutations_n[] = substr($word,0,$length_perm);
}
$i=1;
$permutations_nu = array_unique($permutations_n);
foreach($permutations_nu as $word) {
echo $word." ".$i;
echo "<br>" ;
$i++;
}
?>