Binary Gap

PHP Binary Gap

function binaryGap(int $n): int
{
    $gap    = 0;
    $zeroes = explode('1', trim(decbin($n), '0'));
    foreach ($zeroes as $zero) {
        $len = strlen($zero);
        $gap = $len > $gap ? $len : $gap;
    }

    return $gap;
}

This turns the number into binary, ignores zeroes outside the edges, and finds the longest run of zeroes between 1s.