VCDQuality Forums
Show all 7 posts from this thread on one page

VCDQuality Forums (http://www.vcdhq.com/forum/index.php)
- General Discussion (http://www.vcdhq.com/forum/forumdisplay.php?forumid=4)
-- Calling all eggheads (http://www.vcdhq.com/forum/showthread.php?threadid=82246)


Posted by doctor zoidy on 09-07-2008 01:52 AM:

Calling all eggheads

Okay, here's my math problem... the keypad on my truck has 5 buttons, and a 5 digit code. This leads me to believe that there are 3125 possible codes, requiring 15625 button presses to try all of them.

However, upon testing, if i enter in the first 2 digits, the wrong third digit, then start over with the complete right code, i've pushed 8 digits, and opened the door.

how many button pushes at MAX would it take to open my door, if only the last 5 digits pushed matter?

anyone have any super duty permutation or factorial software to figure this out?

__________________

quote:
Originally posted by Dwaggy
Thats alot of words for someone that sells DVDs out of the back of a truck

quote:
Originally posted by Avenue_1 v3.0b
Read zoidys comment for clarification.


Posted by pHo on 09-07-2008 04:37 AM:

You owe me $20

__________________
563-773-1880

<Dwaggy> i caught you a delicious Bass
<The404> This is because you are an idiot


Posted by doctor zoidy on 09-07-2008 08:00 AM:

I'm aware, refer to THIS THREAD for details, but i'll be paypaling you later...

__________________

quote:
Originally posted by Dwaggy
Thats alot of words for someone that sells DVDs out of the back of a truck

quote:
Originally posted by Avenue_1 v3.0b
Read zoidys comment for clarification.


Posted by case sensitive on 09-07-2008 09:53 AM:

Well it sounds like you already have your answer. I'm pretty sure your max is 15625, code #3125. Your best is code #1 and 5 key presses.

Can't use factorials as you can reuse the same number.

But better yet why not find the factory code printed on the module?

::Let me elaborate with less numbers. Say it is 2 digits with a 0-9 scale

[digit 1] [digit 2] = 10 choices * 10 = 100 numbers or 200 key presses.

If you enter the code just right it will be the max. Think of the code as 99 and it is last on the list and you went down the list as 81..82..83 where each false number would reset the code. You wouldn't know it so you kept going. Lets assume you don't put 89 in before 90 and get lucky and find the code. If we are assuming MAX we are looking for the worst case scenario. It would take it 200 key presses to get it.::


Posted by yoshy on 09-07-2008 11:42 AM:

*waits 200 tries*

fingers crossed for ya

__________________
When life hands you lemons, ask for tequila and salt and call me over.

There comes a point in your life when you realise;
who matters,
who never did,
who won't any more...
and who always will.
So, don't worry about people from your past,
there's a reason why they didn't make it to your future.


Posted by case sensitive on 09-07-2008 07:19 PM:

quote:
Originally posted by yoshy
*waits 200 tries*

fingers crossed for ya



200 was just an example. It will take a lot longer to guess a 5 digit 5 numbered code.

If you stick to entering each code one at a time to find your key presses all you need to do is.

((k^n) * n) = total key presses
Where k is available digits (1-5)
Where n is code length (5)

Odds are he would be able to get the code around the average runtime

((k^n) * n) / 2

If you were just randomly poking numbers there is a very very slight chance that you would never succeed at all.


Posted by takwhori on 09-07-2008 07:41 PM:

this thread gave me a sore head


All times are GMT. The time now is 02:34 AM.
Show all 7 posts from this thread on one page

Powered by: vBulletin Version 2.3.0
Copyright © Jelsoft Enterprises Limited 2000 - 2002.