PHP Programmer interview Baidu face Test

is said to be a Baidu PHP face test, has given an array:

$arr = Array (' B ' => ' A ', ' C ' => ' a ', ' E ' => ' B ', ' d ' => ' B ', ' F ' => ' C ', ' G ' => ' e ', ' h ' => ' f ');

Write an algorithm that completes the conversion to the following format:

array  (     ' a '  => array  (          ' B '  => array  (             ' E '  => array  (                 [0] =>  ' G ',              ),             [0] =>  ' d ',          ),          ' C '  =>  array  (             ' F '  =>  array  (                [0 ] =>  ' h ',             ),         ),     ) 

This structure should belong to a trie tree. At the time of writing, because I did not find the second parameter of the Array_keys () function (Khan one first), and then wrote the following method to achieve.

Function getsomething (& $arr, & $re,  $c = ")  {     $c  or    //Mark     set to True     while ($k when there is a key corresponding to $c  = array_

Search ($c,  $arr))  {    //Loop gets the key with the value $c.         getsomething ($arr,  $re [$c],  $k);     //        unset ($arr [$k]) until the last time there is no key corresponding;         //removal    This element is no longer used         $

flag = true;    &NBSP}     //the normal existing key before the flag is true   description, does not continue to generate the elements of the [0] subscript      if (!  $flag)  return  $re [] =  $c; }//Call getsomething ($arr,  $re,   ' a ');

The

, though a bit of a miracle, is at least implemented. Here is another solution for a netizen using Array_keys ():

function _array_keys ($k, $arr) {

$return = array ();

if ($ret = Array_keys ($arr, $k)) {

foreach ($ret as $v) {

if ($t = _array_keys ($v, $arr)) {

$return [$v] = $t;

else {

$return [] = $v;

}} return

$return;