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

The problem can be simplified if just viewed from the string comparison angle. This is probably faster than array-splitting:

$longest = $tetris[0];  # or array_pop()
foreach ($tetris as $cmp) {
        while (strncmp($longest+"/", $cmp, strlen($longest)+1) !== 0) {
                $longest = substr($longest, 0, strrpos($longest, "/"));
        }
}