Re(5): Puzzle: need a more general algorithm

in reply to Re: Re(3): Puzzle: need a more general algorithm
in thread Puzzle: need a more general algorithm

D'oh!

Fortunately, a man far smarter than I has written an article that you might find useful. ("Pre-Fascicle 2c: Generating all combinations", about halfway down the page. The draft is a .ps.gz file, which is why I didn't link to it directly.)

-- The hell with paco, vote for Erudil! :wq

Comment on Re(5): Puzzle: need a more general algorithm

Replies are listed 'Best First'.
Re: Re (5): Puzzle: need a more general algorithm by Ovid (Cardinal) on Jul 09, 2002 at 15:42 UTC
After giving this some thought, I realized that traditional permutation generators are going to have a problem here. Consider the following four permutations: `11100 11100 11100 11100` [download] Those can be different permutations. The second could have the first and second ones swapped, the third could have the last fourth and fifth zeroes swapped, etc. Even though, to us, they look the same, the permutators that I've played with don't see that (and how would they calculate it?). And it was an interesting coincidence to see the Knuth thread on `/.` this morning. I'm checking it out now. Cheers, Ovid Join the Perlmonks Setiathome Group or just click on the the link and check out our stats.	[reply] [d/l]

Replies are listed 'Best First'.

Re: Re (5): Puzzle: need a more general algorithm
by Ovid (Cardinal) on Jul 09, 2002 at 15:42 UTC

After giving this some thought, I realized that traditional permutation generators are going to have a problem here. Consider the following four permutations:

11100
11100
11100
11100
[download]

Those can be different permutations. The second could have the first and second ones swapped, the third could have the last fourth and fifth zeroes swapped, etc. Even though, to us, they look the same, the permutators that I've played with don't see that (and how would they calculate it?).

And it was an interesting coincidence to see the Knuth thread on /. this morning. I'm checking it out now.

Cheers,
Ovid

Join the Perlmonks Setiathome Group or just click on the the link and check out our stats.

[reply]
[d/l]

In Section Seekers of Perl Wisdom