Coder speed challenge

[SeventhStar]

Hey,

I have an idea for a game. Here are the rules

1. The current Game Master states a simple programming problem.
2. The players post their solutions for the problem in any language that they desire.
2A. If someone intends to take part in a given round but cannot post a solution right away, he should post a message so the others would know and the GM would wait for him.
3. 24 hours later the GM selects the solution he likes best and its author becomes the new GM
4. goto 1

So. Yes, there is not a rule which determines whether the fastest, the smalles or the most obfuscated solution will win. The criteria for the winner depends entirely on the Game Master's taste. And yes, there is no limit to the problems' complexity but we are encouraged to use simple ones, because we usually don't have a lot of free time. I wouldn't ask a problem or try to solve one if I think the solution will take more than an hour.

So let me start and with that give you an example of a simple problem:

Problem 1

The input is a number. You must split this number in prime (and consider '1' to be prime for this one) parts in any possible way. Here is some sample I/O:

I: 1234567 O: 1 2 3 4567; 1 23 4567

I: 111 O: 1 1 1; 11 1; 1 11;

I: 34 O:

I: 7 O: 7

34 cannot be split into prime parts so no output is generated.

I think it should take no more than 30 minutes of thinkig and writing alltogether.

Hope you like the idea and good luck.

[TheCPUWizard]

One additional suggestion. People who want to play should Post a message for a given round, so that we know if this is going to take off. Right now, there could be 1000 players or just me....

[I'm IN]

[SeventhStar]

One additional suggestion. People who want to play should Post a message for a given round, so that we know if this is going to take off. Right now, there could be 1000 players or just me....

[I'm IN]

Sounds fair.
Rules updated.

[PeejAvery]

1234567 has a lot more prime numbers than you have for it. It should have...

1 3 5 7 23 67 4567

I guess that I am by your problem. What do you mean by split every way possible? The following finds all prime numbers possible by combinations (not rearranging the characters) of the string.

<?php
function chk_prime($int){
  for($i = 2; $i < $int; $i++){
    if($int % $i == 0){return false;}
  }
  return true;
}

$str = "1234567"; // 1  3  5  7  23  67  4567

$pos = 0;
for($total_chars = 1; $total_chars <= strlen($str); $total_chars++){
  for($cur_pos = 0; $cur_pos < strlen($str) - $pos; $cur_pos++){
    $cur_str = substr($str, $cur_pos, $total_chars);
    if(chk_prime($cur_str)){
      echo $cur_str . ' ';
    }
  }
  $pos++;
}
?>

[TheCPUWizard]

PeejAvery,

So was I at first... The idea is to NOT look at it as a number at all, but rather as a string of digits. Find the combination of splits such that each split represents a prime number

711 can be split
7-11
71-1
7-1-1
Identify those splits where each of the parts are prime numbers [items #1,#3 definately qualify, not sure if 71 is prime....]

Get it?

[SeventhStar]

1234567 has a lot more prime numbers than you have for it. It should have...

1 3 5 7 23 67 4567

I guess that I am by your problem. What do you mean by split every way possible? The following finds all prime numbers possible by combinations (not rearranging the characters) of the string.
...

Take another look at the problem and at the sample i/o By 'split' I meant a pure geometrical split. Inserting spaces in the appropriate places if you like

1234567 can only be split in two ways
1 2 3 4567
and
1 23 4567

Any other way would either be not composed entirely of prime numbers or won't give the input number if you remove the spaces. Look at how 34 gives no output. It's because 34 is not prime and "3, 4" are not two prime numbers.

<edit> and what TheCPUWizard said in his reply </edit>

[PeejAvery]

Well, in that case I will have to bow/fall/stumble/drop out. I now understand what you are attempting to do, but I don't have that much time.

[SeventhStar]

Well it seems noone, except TheCPUWizard is willing to participate. I suggest we give it another day or so and maybe someone else will post something.

It seemed like a nice idea, though.