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Old 2022-06-02, 00:28   #1
Xyzzy
 
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Aug 2002

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Default June 2022

https://research.ibm.com/haifa/ponde.../June2022.html
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Old 2022-06-15, 13:36   #2
dg211
 
Jun 2016

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To help people check their answers without spoiling the puzzle, these were the last two digits of each of my values for n up to 20.

00, 01, 03, 11, 35, 08, 80, 48, 14, 23, 34, 49, 46, 37, 33, 34, 76, 71, 38, 52
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Old 2022-06-17, 23:51   #3
uau
 
Jan 2017

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Has anyone here tried to calculate values especially far? I've computed up to 23 (with a fast enough program that calculating the next few values would be realistic if I left it running for a while).
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Old 2022-06-19, 05:30   #4
Dieter
 
Oct 2017

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Quote:
Originally Posted by dg211 View Post
To help people check their answers without spoiling the puzzle, these were the last two digits of each of my values for n up to 20.

00, 01, 03, 11, 35, 08, 80, 48, 14, 23, 34, 49, 46, 37, 33, 34, 76, 71, 38, 52
n=21: …77 ?
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Old 2022-06-19, 09:58   #5
Kebbaj
 
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Quote:
Originally Posted by uau View Post
Has anyone here tried to calculate values especially far? I've computed up to 23 (with a fast enough program that calculating the next few values would be realistic if I left it running for a while).
@uau
For confirmation :
n 22 finish by 39
n 23 finish by 62
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Old 2022-06-19, 14:03   #6
uau
 
Jan 2017

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Those values match what I got. There are some things I'd say about the calculation, but they'd be kind of spoilery, so perhaps better left for private messages or after the month is over.
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Old 2022-06-20, 09:47   #7
dg211
 
Jun 2016

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My (fairly naive, single-threaded) code took about two and a half hours to do n=20, and it goes up by a factor of about 4 for each increase in n. By multithreading it I think I could do n=23 or even n=25 in a not totally absurd time, but wondering if other people have faster approaches?
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Old 2022-06-20, 13:42   #8
uau
 
Jan 2017

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Well my code is faster, but not a totally different approach - still proportional to the overall number of polyominoes. I'll send details in PM.
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Old 2022-06-21, 17:29   #9
KangJ
 
Jul 2015

10112 Posts
Default Question about algorithm

I am seriously struggling with this problem.

If there is an algorithm that efficiently creates polyomino without duplicates, what would it be?

The method of creating and saving all polyominos to check for duplicates is easily limited around N=15.

Is it correct to save all polyominos of size N-1 to create a new polyomino of size N?

I tried to classify polyominos by width size, but the method of saving all polyominos to check for duplicates also runs into a limit as N increases.

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