04. NonRepeatingDigits.php

<?php

$n = 1234;
$arr = array();

for ($i = 102; $i <= $n; $i++) {
    if(strlen($i) >= 4) {
        break;
    }
    $firstDigit = (int)($i % 10);
    $secondDigit = (int)(($i / 10) % 10);
    $thirdDigit = (int)($i / 100);

    if($firstDigit != $secondDigit && $firstDigit != $thirdDigit) {
        if($secondDigit != $thirdDigit) {
            array_push($arr, $i);
        }
    }
}
if(count($arr) > 0) {
    echo implode(', ', $arr);
} else {
    echo "no";
}
?>