Re: Hofstadter Metapuzzle

Thankfully, the statement doesn't "overflow" so this program works:

#!/usr/bin/perl -w

use strict;

my $statement = "The number of 0s in this sentence is _, of 1s is _, o
+f 2s is _, of 3s is _, of 4s is _, of 5s is _, of 6s is _, of 7s is _
+, of 8s is _, and of 9s is _.";

my @index;
my $resume = 0;

while (($resume = index($statement, "_", $resume)) && $resume > 0)
{
        push (@index, $resume++);
}

my $changed;

do {
        $changed = 0;

        for my $n (0 .. $#index)
        {
                my $count = (grep { /$n/ } split (//, $statement));
                my $old_count = substr($statement, $index[$n], 1);

                if ($count ne $old_count)
                {
                        substr($statement, $index[$n], 1) = $count;
                        $changed++;
                }
        }
} while ($changed);

print $statement,"\n";
[download]

The great mystery is finally revealed. Golf anyone?

Comment on Re: Hofstadter Metapuzzle Download Code

Replies are listed 'Best First'.
Re: Re: Hofstadter Metapuzzle by MeowChow (Vicar) on May 22, 2002 at 23:51 UTC
Nice work. Iterative processes are hit-or-miss with these sorts of problems, though. They depend on your initial state, can degenerate into cycles, and are not necessarily capable of producing all possible solutions. I wonder if this program can be tweaked to produce the second solution? MeowChow s aamecha.s a..a\u$&owag.print	[reply]
Re^3: Hofstadter Metapuzzle by tadman (Prior) on May 23, 2002 at 00:29 UTC
Some puzzles like this don't settle into a steady state, leaving the logical equivalent of a "flip-flop" circuit, the classic paradoxical "This statement is false."-type problem, or two self-defeating, self-reinforcing arrangements like in the "Life" game. I think if you seed the initial statement differently, it might settle on a different possibility, though of course, this particular implementation uses the underscores for placement, so that will have to change.	[reply]
(MeowChow) Re^4: Hofstadter Metapuzzle by MeowChow (Vicar) on May 23, 2002 at 00:45 UTC
Sure, you can seed it with the second solution :) MeowChow s aamecha.s a..a\u$&owag.print	[reply]
Re: Re: Hofstadter Metapuzzle by jynx (Priest) on May 23, 2002 at 17:56 UTC
Not counting the data section, i get a score of 128. i'm not counting the data section since anyone golfing will need the input, so it shouldn't be counted. That's my theory at least. Anyway, here's my attempt: `#23456789_123456789_123456789_123456789_123456789_123456789_123456789_ $_=<DATA>;push@_,@+while/_/g;{for$a(0..$#_){substr($_,$_[$a]-1,1 )=$;,$\|++if($;=@{[/$a/g]})!=substr$_,$_[$a]-1,1}$\|--&&redo}print __DATA__ The number of 0s in this sentence is _, of 1s is _, of 2s is _, of 3s +is _, of 4 s is _, of 5s is _, of 6s is _, of 7s is _, of 8s is _, and of 9s is _ +.` [download] On the other hand, here's a much shorter 77 byte solution that's less interesting. It uses the same data section as above. Please note in both cases there should be no "\n"s in the data. `sub{$a=<DATA>;$a=~s,($_.*?)_,$1.pop,efor-1..9;print$a}->(1,1,2,1,1,1,2 +,3,7,1)` [download] enjoy, jynx	[reply] [d/l] [select]