Help with permutations.

[Jragon]

Hiya guys,

 

I've never used 'Hiya' =]

 

Well, I need a little help. I've got a permutation function that Mchl gave me:

function permute($array,$positions,&$perms,$previous = null) {
  if($positions > 0) {
   if(!isset($previous)) {
     $previous = array();
   }
   
    foreach($array as $element) {
     $tempPrevious = $previous;
     $tempPrevious[] = $element;
     permute($array,$positions-1,$perms,$tempPrevious);
   }
  } else {
    $perms[] = $previous;
  }
}

 

It works fine, but I need to take it to the next level (you might not call it permutation). What I need it to do:

• Use's all characters in ASCII thing
  
• start from 1 characters and goto 50 characters
  
• When it gets to Maximum execution time it remembers where it was and can be restarted and will start form there
  
• MD5 the output
  
• Add the md5 hash to a database with the origanal output
  
• Work
  

 

So that is what I need it to do. If it is possible Please tell me how it can be done, if not then tell me how much of it is possible.

 

Thanks

 

Jragon

[GoneNowBye]

permutations are similar to changing number base.

 

permutation number = 5

n (options) = a and b

 

keep removing from left to right, the highest value of n you can, times it by position from right * n each row.

 

think of it like change, if we have a 1p 2p 5p 10p 20p 50p coins

 

and i want 57 pence, you keep removing the biggest coin you can, 50, (leaving 7) 5, leaving 2, and 2 leaving 0

 

so 50 + 5 + 2 pence coins.

 

i'm in a rush, sorry.

[Mchl]

For your consideration:

There are 95 printable ASCII characters. To store all possible 50 character long strings  you need (50^95)*50 = 1.26*10^163B = Do you have that much storage avialable?

[GoneNowBye]

Mtchl loving the maths, but belive me from experance, this is not computationally feasable, in terms of time, you're also better off not caching the permutations, GL though

[Mchl]

Mtchl loving the maths, but belive me from experance, this is not computationally feasable

 

That's exactly what I'm hinting at with these numbers (in case that's not clear)