问2021-09-13：整数转罗马数字？

输入: 3
输出: "III"

<?php
function intToRoman($num) 
{

    $n = intval($num);
    $result = '';
    $lookup = array(
        'M' => 1000, 'CM' => 900, 'D' => 500, 'CD' => 400,
        'C' => 100, 'XC' => 90, 'L' => 50, 'XL' => 40,
        'X' => 10, 'IX' => 9, 'V' => 5, 'IV' => 4, 'I' => 1
    );
    foreach ($lookup as $roman => $value) 
    {
        // Look for number of matches
        $matches = intval($n / $value);
        // Concatenate characters
        $result .= str_repeat($roman, $matches);
        // Substract that from the number
        $n = $n % $value;
    }
    return $result;

}