03. Working Days

<?php
$from = $_GET['dateOne'];
$to = $_GET['dateTwo'];
$holidays = preg_split("/\s+/", $_GET['holidays'], -1, PREG_SPLIT_NO_EMPTY);

//$from = '17-12-2014';
//$to = '31-12-2014';
//$holidays = array('31-12-2014', '24-12-2014', '08-12-2014');

$workdays = array();
for ($currDate = date("d-m-Y", strtotime($from)); $currDate < date("d-m-Y", strtotime($to)); $currDate = date("d-m-Y", strtotime($currDate . ' + 1 days'))) {
    if (date('N', strtotime($currDate)) != 6 && date('N', strtotime($currDate)) != 7) {
        foreach ($holidays as $holiday) {
            if (date('d-m-Y', strtotime($currDate)) != date('d-m-Y', strtotime($holiday))) {
                $workdays[] = date('d-m-Y', strtotime($currDate));
            }
        }
    }
}
echo '<ol>' . "\n";
foreach (array_unique($workdays) as $day) {
    echo '<li>' . $day . '</li>' . "\n";
}
echo '</ol>';