10/1/2015

rank.php

function containsKey($key_para, $array)
{
    foreach ($array as $key => $value) {
        if ($key_para === $key) {
            return true;
        }
    }
    return false;
}

function findRank($perm)
{
    $a               = array();
    $rank            = 1;
    $suffix = 1;

    $length     = strlen($perm);
    $characters = str_split($perm);

    for ($i = $length - 1; $i > -1; $i--) {
        $char  = $characters[$i];
        $count = 1;

        if ($this->containsKey($char, $a)) {
            $count = $a[$char];
            $count++;
            $a[$char] = $count;
        } else {
            $a[$char] = $count;
        }
        foreach ($a as $key => $value) {
            if (ord($key) < ord($characters[$i])) {
                $rank = $rank + (($suffix * $value) / $count);
            }
        }

        $suffix = $suffix * ($length - $i);
        $suffix = ($suffix / $count);
    }

    return $rank;
}