Desafio Folha

desafio.php

$g = array(
    'halley'  => 'amarelo',
    'encke'   => 'vermelho',
    'wolf'    => 'preto',
    'kushida' => 'azul'
);

$l = array(
    'a' => 1,
    'z' => 26
);

$r = array();

foreach ($g as $o => $c) {
    $ao = str_split($o);
    $ac = str_split($c);

    $mo = 1;
    foreach ($ao as $fao) {
        if ($l[$fao]){
            $mo = $mo * $l[$fao];
        } else {
            $l[$fao] = ord($fao) - ord('a') + 1;
            $mo = $mo * $l[$fao];
        }
    }
    $ro = $mo % 45;

    $mc = 1;
    foreach ($ac as $fac) {
        if ($l[$fac]){
            $mc = $mc * $l[$fac];
        } else {
            $l[$fac] = ord($fac) - ord('a') + 1;
            $mc = $mc * $l[$fac];
        }
    }
    $rc = $mc % 45;

    if ($ro != $rc){
        echo $c.'<br>';
    }

}