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 Xyzzy 2022-01-05 17:50

January 2022

[url]https://research.ibm.com/haifa/ponderthis/challenges/January2022.html[/url]

 Max0526 2022-01-07 05:04

Min/max for 7/5 case? 446/3051?

 Zoozie 2022-01-07 18:29

I can confirm those numbers...

/Thomas Egense

 Max0526 2022-01-07 18:53

[QUOTE=Zoozie;597383]I can confirm those numbers...

/Thomas Egense[/QUOTE]
Thank you! I sent my 7/5 solution yesterday.
What did you code in? What was the total runtime?
I coded in Python, it took ~24 minutes to solve the n = 7, d = 5 case. Java should be faster for sure.
Is anybody working on n = 8, d = 6?
It would be nice to see the min/max counts (please don't post the solutions, just the counts).

 Zoozie 2022-01-07 19:01

[QUOTE=Max0526;597387]Thank you! I sent my 7/5 solution yesterday.
What did you code in? What was the total runtime?
I coded in Python, it took ~24 minutes to solve the n = 7, d = 5 case. Java should be faster for sure.
Is anybody working on n = 8, d = 6?
It would be nice to see the min/max counts (please don't post the solutions, just the counts).[/QUOTE]

It took about 2 minutes to solve in java for n=7,d=5. I did not really optimize except first generating cache of small primes. The n=8, d=6 was solved in some hours, did not time it.

For n=8, d=6:
wheeel for maximum solution had 1992 primes
wheel for minimum solution had 741 primes.

 Max0526 2022-01-07 22:00

[QUOTE=Zoozie;597388]It took about 2 minutes to solve in java for n=7,d=5. I did not really optimize except first generating cache of small primes. The n=8, d=6 was solved in some hours, did not time it.

For n=8, d=6:
wheeel for maximum solution had 1992 primes
wheel for minimum solution had 741 primes.[/QUOTE]
Zoozie, could you please look up the max/min scores, not the number of primes?
Thank you!

 Walter 2022-01-09 21:46

I can confirm the scores for n = 7 and d = 5.

For n = 8 and d = 6, I get the following scores:
max: 19690
min: 6905

Average execution time (using Cython, and only one thread - could be easily parallelized):
n = 7, d = 5: ~120 seconds
n = 8, d = 6: ~1100 seconds

 SmartMersenne 2022-01-09 22:35

[QUOTE=Walter;597506]I can confirm the scores for n = 7 and d = 5.

For n = 8 and d = 6, I get the following scores:
max: 19690
min: 6905

Average execution time (using Cython, and only one thread - could be easily parallelized):
n = 7, d = 5: ~120 seconds
n = 8, d = 6: ~1100 seconds[/QUOTE]

I have a circle with score 21617 but my min is not even close to yours.

 Max0526 2022-01-10 04:24

> but my min is not even close to yours.

It might be that the problem got edited after the initial posting. The first sentence reads:
"Seven [B]distinct[/B] digits are placed on a circle." (also, "placed" is misspelled in the original)
I had much lower min scores (60 instead of 446) when the circle of 7 was allowed to have duplicates. No duplicates allowed, neither in the circle, nor in the numbers.

Thank you for posting your scores and times!

 SmartMersenne 2022-01-10 04:49

[QUOTE=Max0526;597533]> but my min is not even close to yours.

I had much lower min scores (60 instead of 446) when the circle of 7 was allowed to have duplicates. No duplicates allowed, neither in the circle, nor in the numbers.
[/QUOTE]

I meant my minimum is much higher. I do hope someone who solved the bonus can post their scores for min and max.

 Walter 2022-01-10 05:38

[QUOTE=SmartMersenne;597535]I meant my minimum is much higher. I do hope someone who solved the bonus can post their scores for min and max.[/QUOTE]

Just to add on to my previous response: the number of primes that can be generated with the max and min wheel in my solution corresponds to the same values that Zoozie posted (741 primes for the min wheel and 1992 primes for the max wheel). Now, to be fair, I see multiple wheels that generate the same number of primes, but it gives me some additional confidence that my solution is right.

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