Find length of initial segment matching mask on Arrays

Question

Given an array with n values, for example:

$arr[] = \'ABCDEFABC\';
$arr[] = \'ABCDEFDEF\';
$arr[] = \'ABCDEFGHI\';
$arr[] = \'ABCDEFJKL\';

how

Answer 1

I've come up with a solution for my first problem:

EDIT: BUGGY!

$arr = array();

// Bug: ABCDEFX

$arr[] = 'ABCDEFAXC';
$arr[] = 'ABCDEFDXF';
$arr[] = 'ABCDEFGXI';
$arr[] = 'ABCDEFJXL';

/*
$arr[] = 'ABCDEFABC';
$arr[] = 'ABCDEFDEF';
$arr[] = 'ABCDEFGHI';
$arr[] = 'ABCDEFJKL';
*/

// ABCDEF    
$result = implode('', call_user_func_array('array_intersect_assoc', array_map('str_split', $arr)));

One left to go now...