Tetris-ing an array

Question

Consider the following array:

/www/htdocs/1/sites/lib/abcdedd
/www/htdocs/1/sites/conf/xyz
/www/htdocs/1/sites/conf/abc/         


        

Answer 1

You could remove prefix the fastest way, reading each character only once:

function findLongestWord($lines, $delim = "/")
{
    $max = 0;
    $len = strlen($lines[0]); 

    // read first string once
    for($i = 0; $i < $len; $i++) {
        for($n = 1; $n < count($lines); $n++) {
            if($lines[0][$i] != $lines[$n][$i]) {
                // we've found a difference between current token
                // stop search:
                return $max;
            }
        }
        if($lines[0][$i] == $delim) {
            // we've found a complete token:
            $max = $i + 1;
        }
    }
    return $max;
}

$max = findLongestWord($lines);
// cut prefix of len "max"
for($n = 0; $n < count($lines); $n++) {
    $lines[$n] = substr(lines[$n], $max, $len);
}