PHP Quiz

**seanf** · May 29, 2003 08:03

You looked!

Your question Mr anode

Sean

**anode** · May 29, 2003 08:09

I didn't, it popped up on one of the PHP sites' RSS feeds earlier today and I took note.

Ok...

Turn this array:
Apple =>Jobs
Microsoft =>Gates
Oracle => Ellison
Sun => McNealy

into this one

ylaencm => nus
nosille =>elcaro
setag => tfosorcim
sboj => elppa

Using the least lines of code possible

**Technosailor** · May 29, 2003 08:09

nah! I am PHP.

**seanf** · May 29, 2003 08:26

PHP Code:


<?php



    $firstArr = array ( 'Apple' => 'Jobs', 'Microsoft' => 'Gates', 'Oracle' => 'Ellison', 'Sun' => 'McNealy');



    $firstArr = array_flip ( array_reverse ( $firstArr ) );



    foreach ( $firstArr as $key => $val ) {



        $key = strrev ( strtolower ( $key ) );



        $secondArr[$key] = strrev ( strtolower ( $val ) );



    }



?>

Sean

**anode** · May 29, 2003 08:35

I think it may be able to be just a bit shorter(I'm specifically thinking of all the Lisp-like array functions), but I'll accept that.

**seanf** · May 29, 2003 08:38

Did you come up with a way to do it? I'm sure it could be shorter

Anybody want to ask a question?

Sean

**anode** · May 29, 2003 08:41

When I have my coffee I will. I forget the specifics of working with array_map and friends, but I had a rough plan of how I'd do it when I came up with the question.

**Jeff Lange** · May 29, 2003 08:43

PHP Code:


$array = array_change_key_case(array_reverse(array_flip(array('Apple' => 'Jobs', 'Microsoft' => 'Gates', 'Oracle' => 'Ellison', 'Sun' => 'McNealy'))), CASE_LOWER);
foreach ($array as $key => $content) $new_array[strrev($key)] = strtolower(strrev($content));

You said shortest number of lines right?

**anode** · May 29, 2003 08:47

Originally Posted by cyborg from dh

PHP Code:


$array = array_change_key_case(array_reverse(array_flip(array('Apple' => 'Jobs', 'Microsoft' => 'Gates', 'Oracle' => 'Ellison', 'Sun' => 'McNealy'))), CASE_LOWER);

foreach ($array as $key => $content) $new_array[strrev($key)] = strtolower(strrev($content));

You said shortest number of lines right?

Now that you mention it

PHP Code:


foreach ((array_change_key_case(array_reverse(array_flip(array('Apple' => 'Jobs', 'Microsoft' => 'Gates', 'Oracle' => 'Ellison', 'Sun' => 'McNealy'))), CASE_LOWER)) as $key => $content) $new_array[strrev($key)] = strtolower(strrev($content));

In your face, Perl!

**Jeff Lange** · May 29, 2003 08:48

damn you!

**Jeff Lange** · May 29, 2003 08:54

PHP Code:


foreach(array_reverse(array_flip(array('Apple'=>'Jobs','Microsoft'=>'Gates','Oracle'=>'Ellison','Sun'=>'McNealy')))as$k=>$c)$n[strtolower(strrev($k))]=strtolower(strrev($c));

there. [img]images/smilies/tongue.gif[/img]

**seanf** · May 31, 2003 08:02

Let's have a question from someone

Sean

**Jeff Lange** · Jun 19, 2003 15:51

PHP Code:


define('C', 'f');
define('S' . strtoupper(str_rot13(C)), 'c', 0);
$d = '2.';
$q = 'S';
list ($x, $y) = array('p', 'gg');
$b = substr(str_rot13('a'.$x.'xy'.$y), 1, -4);
$c = ($e = 'a') . (25 / 2) . ($f = 22 | 45);
${'a1'.${((${'h'} = SS) ? ++$h : 0)}.'5'.(($g = 126 / 5) + ($g * 1.5))} = (float) ($d . ($f * 1.9047619047619));
$a = ${${$b}};
ob_start();
var_dump(${$e});
eval('${S'.$q.'} = substr(strrchr(ob_get_contents(), substr(\'(\',0)), 1, -(int) substr($c, 2, -2)) . round(floor($$b));');
ob_end_clean();
echo $$b;

What's the output?

**samsm** · Jun 19, 2003 20:54

Oh, man... so tempting to simply run code... but I can resist. :-)

Good one, cyborg! Either really evil or there's a trick to it, I'm banking on the later as the former would require doing str_rot13 conversions by hand.

Man, I had never even heard of str_rot13 before. That's a wacky function.

Ok, I've stared at this for about five minutes, and I'm not coming up with a trick to it. Hopefully someone else is more devious than I. :-)

**anode** · Jun 19, 2003 21:10

Sam, do it on paper.

**samsm** · Jun 19, 2003 21:18

But wouldn't that be kind of like just running the script?

If I follow the documentation and do it by hand it'll essentially just execute like PHP would do it... only much much much slower.

**anode** · Jun 19, 2003 21:21

Originally Posted by samsm

But wouldn't that be kind of like just running the script?

If I follow the documentation and do it by hand it'll essentially just execute like PHP would do it... only much much much slower.

Sure, but it's a learning experience, as opposed to running it.

Personally, I got tripped up by the bitwise stuff and gave up. I'll try it if I ever read more Knuth

**Jeff Lange** · Jun 19, 2003 21:48

There's no trick to it, I started out with a basic thing, and kept adding more and more stuff.

The bitwise thing is about the hardest part.

(Thought I'd revive this thread with something more difficult [img]images/smilies/wink.gif[/img], oh yeah, and doing it on paper's not cheating, you are still figuring it out, and the PHP Parser's not.)

**Jeff Lange** · Jun 19, 2003 22:31

I'll give you hint on what the value of the bitwise equation: It's half of double 6.3, that's all i'll say.

**samsm** · Jun 19, 2003 22:53

Oh well, the lazy part of me was hoping that there was some part at the end that made most of the equation irrelevant.

Whoever gets this needs to show a proof to demonstrate that they did this by hand. :-)

**Jeff Lange** · Jun 22, 2003 14:54

bump. somebody's gotta do it....

**samsm** · Jun 22, 2003 19:52

Crap. Ok, the whole thing is a bit daunting but none of the steps are THAT bad.

How about this. Each of use will simplify it one step and post the result and perhaps a brief rationalization for that simplification. We'll continue until it's solved.

I'll begin.

(Used this as help with the bitwise stuff)

PHP Code:


define('C', 'f');

define('SPc', 0);



$d = '2.';

$q = 'S';



$x = 'p';

$y = 'gg';





$b = 'c';



// $c = '1' . (25 / 2) . ($f = 22 | 45);



/*

22 / 2 == 11 r 0

11 / 2 == 5  r 1

 5 / 2 == 2  r 1

 2 / 2 == 1  r 0

 1 / 2 == 0  r 1



10110 = 22

*/





/*



45 / 2 == 22 r 1

22 / 2 == 11 r 0

11 / 2 == 5  r 1

 5 / 2 == 2  r 1

 2 / 2 == 1  r 0

 1 / 2 == 0  r 1



101101 = 45

*/



/*

bitwise or:

 10110

101101

------

111111



1+2+4+8+16+32 == 63



so...

$c = '1' . 12.5 . 63;

so...

*/



$c = 112.563;



${'a1'.${((${'h'} = SS) ? ++$h : 0)}.'5'.(($g = 126 / 5) + ($g * 1.5))} = (float) ($d . ($f * 1.9047619047619));

$a = ${${$b}};

ob_start();

var_dump(${$e});

eval('${S'.$q.'} = substr(strrchr(ob_get_contents(), substr(\'(\',0)), 1, -(int) substr($c, 2, -2)) . round(floor($$b));');

ob_end_clean();

echo $$b;

There. Hope errors didn't slip in, as humans are prone to that sort of thing. I'm done for the evening as far as this thing is concerned, someone else pitch in a little and I'll get rid of a few more lines. :-)

**Jeff Lange** · Jun 23, 2003 00:30

the second define should be

PHP Code:


define('SS', 'c', 0);

You made another obvious mistake, however you've simplified it so much i'm not sure why you stopped, being so close and all....

**Azmo** · Jun 23, 2003 04:33

Originally Posted by cyborg from dh

bump. somebody's gotta do it....

cyborg: I found the answer after quite a bit of work, but I got the wrong answer at first (I checked). After that I did manage to get the right result, but since I'd already seen the correct answer, it feels a bit like cheating.

I can post a complete solution if it's ok with everyone though.

**Hartmann** · Jun 23, 2003 06:47

Originally Posted by Azmo

cyborg: I found the answer after quite a bit of work, but I got the wrong answer at first (I checked). After that I did manage to get the right result, but since I'd already seen the correct answer, it feels a bit like cheating. [img]images/smilies/xeye.gif[/img]

I can post a complete solution if it's ok with everyone though. [img]images/smilies/smile.gif[/img]

Please do. I would be interested in seeing it!

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