Ask how to convert a multidimensional array to a two-dimensional array

How do I convert a multidimensional array to a two-dimensional array?
For example, an infinite menu, after recursion is a multidimensional array, I want to convert this multidimensional array into a two-dimensional array and re-sort after the foreach, how can I write this function?
------Solution--------------------

$a = Array (
0=>array (
' CategoryID ' =>1,
' Name ' = ' AA1 ',
' Parent ' =>0,
' Childs ' =>array (
0=>array (
' CategoryID ' =>2,
' Name ' = ' BB1 ',
' Parent ' =>1,
' Childs ' =>array (
0=>array (
' CategoryID ' =>3,
' Name ' = "CC",
' Parent ' =>2,
' Childs ' =>array (
0=>array (
' CategoryID ' =>4,
' Name ' = ' dd1 ',
' Parent ' =>3,
),
1=>array (
' CategoryID ' =>5,
' Name ' = ' DD2 ',
' Parent ' =>3,
),
),
),
),
),
1=>array (
' CategoryID ' =>6,
' Name ' = ' BB2 ',
' Parent ' =>1,
),
),
),
1=>array (
' CategoryID ' =>7,
' Name ' = ' AA2 ',
' Parent ' =>0,
)
);
function imp ($tree, $children = ' childs ') {
$imparr = Array ();
foreach ($tree as $w) {
if (Isset ($w [$children])) {
$t = $w [$children];
Unset ($w [$children]);
$imparr [] = $w;
if (Is_array ($t)) $imparr = Array_merge ($imparr, IMP ($t, $children));
} else {
$imparr [] = $w;
}
}
return $imparr;
}
Print_r (Imp ($a));

array 
 (
 [0] = = Array 
 (
 [CategoryID] = 1 
 [Name] = AA1 
 [parent] + 0 
) 
 
 [1] = = Array 
 (
 [Cat Egoryid] = 2 
 [name] = BB1 
 [parent] + 1 
) 
 
 [2] = = Array (
 [CategoryID] = 3 
 [name] + CC 
 [Parent] = 2 
            ) 
 
 [3] = = Array 
 (
 [CategoryID] + 4 
 [name] = + DD1 
 [Parent] = 3 
) 
 
 [4] = = Array 
 (
 [CategoryID] = 5 
 