mozy contest: problem 2 PHP solution

Nicholas Leippe nick at leippe.com
Mon Nov 6 10:03:25 MST 2006


The second problem gave one number per line.
For each number, output (sorted descending) all smaller positive integers that 
were both multiples of 7 and whose reverse (string) was also a multiple of 7.

<?

while ($line = fgets(STDIN)) {
        $n = (int) $line;
        $res = array();
        $i = $n;
        while (!isMultof7($i)) {
		$i--;
	}
        for (; $i >= 0; $i -= 7) {
                if (isMultof7((int) strrev($i)))
                {
                        echo "$i\n";
                }
        }
}

function isMultof7($i) {
        $d = (int) ($i / 7);
        return $d * 7 == $i;
}



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