Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020
Administrator
Subject: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-02 12:01 PM (#28158) (#28158) Top


2000500100100100202020
Location: India
Name of Test: Mean Minis

Author: Rakesh Rai

Dates: 8th to 13th May 2020

IB: Expected on or before 5th May
Administrator
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-05 5:57 PM (#28180 - in reply to #28158) (#28180) Top


2000500100100100202020
Location: India

Instruction Booklet


The IB is available now at the contest page: http://logicmastersindia.com/2020/05S/

Points table shall be shared before the start of the contest.

BogdanG
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-05 10:30 PM (#28184 - in reply to #28158) (#28184) Top




Posts: 5

Location: Romania
Hi, maybe a missed by mistake, but still I did not saw in instruction the duration of test. 90 minutes?
Timjamiller
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-05 11:14 PM (#28185 - in reply to #28158) (#28185) Top




Posts: 13

Location: USA
Clarification: In "Sequence", the instructions say digits "along a line" will form an arithmetic sequence. Does this mean that they will be a sequence in order of appearance (as shown also in the answer) or could they be randomly located on the line as in Renban?

Edited by Timjamiller 2020-05-05 11:18 PM
Administrator
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-05 11:47 PM (#28187 - in reply to #28184) (#28187) Top


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Location: India
BogdanG - 2020-05-05 10:30 PM

Hi, maybe a missed by mistake, but still I did not saw in instruction the duration of test. 90 minutes?

Probably missed. We shall add along with points later.
However, it is there (90 minutes) on the contest page.
rakesh_rai
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-05 11:49 PM (#28188 - in reply to #28185) (#28188) Top



Mean Minis (2020) Author

Posts: 749
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Location: India
Timjamiller - 2020-05-05 11:14 PM

Clarification: In "Sequence", the instructions say digits "along a line" will form an arithmetic sequence. Does this mean that they will be a sequence in order of appearance (as shown also in the answer) or could they be randomly located on the line as in Renban?

They will be in sequence from one end to the other.
Timjamiller
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-06 12:10 AM (#28189 - in reply to #28158) (#28189) Top




Posts: 13

Location: USA
I think that the X-sums in the IB has an alternate solution. Not sure if I can attach a screenshot, so I'll write out the alternate numbers:

846957
759864
597486
468795
975648
684579
Administrator
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-06 12:40 AM (#28190 - in reply to #28158) (#28190) Top


2000500100100100202020
Location: India

(Updated) Instruction Booklet


An updated version of the IB is available (3:55 pm IST on 6th May) at the contest page.

Changes:
1) Duration of the contest added on Page 1
2) X Sums and Odd Even Count example grid corrected.
3) General Rules on Page 3 updated for the contest

Thanks BogdanG and Timjamiller!

Timjamiller
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-06 1:10 AM (#28191 - in reply to #28158) (#28191) Top




Posts: 13

Location: USA
I guess I have another clarification question for X-Sums. Can a clued row or column begin with a number that exceeds 6? If so, would the total be the same as though it were a 6?
rakesh_rai
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-06 7:27 AM (#28192 - in reply to #28191) (#28192) Top



Mean Minis (2020) Author

Posts: 749
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Location: India
Timjamiller - 2020-05-06 1:10 AM

I guess I have another clarification question for X-Sums. Can a clued row or column begin with a number that exceeds 6? If so, would the total be the same as though it were a 6?

It cannot exceed 6.
Administrator
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-08 2:59 PM (#28211 - in reply to #28158) (#28211) Top


2000500100100100202020
Location: India

Puzzle Booklet (PB)


The password protected PB is now available for download at the contest page: http://logicmastersindia.com/2020/05S/

There is no separate feedback page for this test. Feedback, if any, can be directly entered in this thread.

Administrator
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-08 3:00 PM (#28212 - in reply to #28158) (#28212) Top


2000500100100100202020
Location: India

Final Instruction Booklet (IB)


The updated Instruction Booklet (IB) is now available for download at the contest page: http://logicmastersindia.com/2020/05S/

Points Table was added.

rob
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-09 1:07 AM (#28213 - in reply to #28158) (#28213) Top


Classics & Regions (PR 2016/17) Author

Posts: 160
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Location: Germany
Great contest, loved the concept, thanks Rakesh!

It was tough because I felt I rarely had time to really think about a puzzle (though maybe I should have?) and was constantly in experimental mode. Might have finished if I hadn't wasted time with being unsure/unaware of constant arithmetic sequences, but the Little Killer seemed impenetrable. I worked it out cleanly afterwards, and there's a fair path -- I imagine the same would be true of the various puzzles where I wasn't even close to finding that.
ByronosaurusRex
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-09 5:33 AM (#28214 - in reply to #28158) (#28214) Top




Posts: 3

Location: Canada
Alright, so before I discuss my solving experience, I should mention that I've made a habit of solving LMI sudoku competitions exclusively through the online interface. Sometimes I find myself questioning that decision, partly because I think I'm a bit faster on pencil and paper despite the extra time keying in solution codes, and partly because I worry that without specialized notation, individual puzzles might slip out of my grasp. (They generally don't, but they still have the potential to do so.)

This competition has me feeling very mixed emotions about that decision, because on one hand, there were several times when I found myself sorely missing such notational methods. But on the other hand, necessity is the mother of invention, and I wound up adopting an aggressive trial-and-error approach that would have been a total mess on paper -- I've never made so much use of the Reset button. I could never have gotten away with doing it on 9x9 grids, but in this particular scenario (6x6, incomplete number sets to work out) doing lots of guesswork paid off startlingly (disappointingly?) well at times. I might like to revisit some of the harder puzzles later and figure out how to actually solve them rather than just stumbling onto the right set of digits by making assumptions. The Kropki in particular fell pretty fast to "Let's just assume this square is also 7".

It felt like an accomplishment to finish the round, and yet it didn't feel like I'd truly earned the accomplishment. It's a strange feeling -- not necessarily unwelcome, because the experience was quite a thrill ride, but decidedly different than what I'm accustomed to. I enjoyed it, (EDIT: I also really loved the concept of the round), and I'd be okay with experiencing a round like this one again (ideally in a similar 'off-week/casual' setting), but if I ever find myself resorting to flat-out trial and error this much at a WSPC round I might wonder if I'm irrevocably past my prime. :-P

Setting aside the dirty, dirty feeling of guessing my way through so many puzzles in one session, I should mention that Sequence felt particularly overvalued -- I skipped past it at first because I thought I was a bit short on time to risk it, then came back later and quickly steamrolled through the full solution path in just over 3 minutes. Its difficulty is almost entirely contained in the "same digit repeated is an arithmetic progression" a-ha moment, which feels like the puzzling equivalent of a trick question; to its credit, the puzzle made eliminating all other options for that line incredibly efficient, so it was probably the best possible execution of that trick, but 9 points still felt like too great a reward for spotting it so quickly.

Edited by ByronosaurusRex 2020-05-09 5:36 AM
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Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-09 7:15 AM (#28215 - in reply to #28158) (#28215) Top


2000500100100100202020
Location: India

Score page


A minor fix was applied to the score page.
It was showing additional bonus for some participants (who had not completed the set) earlier.

rakesh_rai
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-09 7:20 AM (#28216 - in reply to #28213) (#28216) Top



Mean Minis (2020) Author

Posts: 749
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Location: India
rob - 2020-05-09 1:07 AM

Great contest, loved the concept, thanks Rakesh!

It was tough because I felt I rarely had time to really think about a puzzle (though maybe I should have?) and was constantly in experimental mode. Might have finished if I hadn't wasted time with being unsure/unaware of constant arithmetic sequences, but the Little Killer seemed impenetrable. I worked it out cleanly afterwards, and there's a fair path -- I imagine the same would be true of the various puzzles where I wasn't even close to finding that.
Thanks Rob! Constant arithmetic sequences would always be in the doubtful category, unless explicitly mentioned elsewhere. That is the reason the IB example had one sequence of 999.

I will share the (intended) starts for each puzzle later.
ashaash11ash
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-09 3:59 PM (#28217 - in reply to #28158) (#28217) Top


PR 2019 (MII and Regions) Author

Posts: 37
20
Location: india
Very nice contest Rakesh. I loved the path for each Sudoku i solved. I never looked at the IB and never realized about the Constant AP. Wasted a lot of time (more than 20 min) and at last realized that it should be broken????.
After the contest saw the IB.

Great test though..
bob
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-09 8:33 PM (#28219 - in reply to #28158) (#28219) Top




Posts: 55
2020
Location: USA
Way, way, way too hard for a timed test in my opinion...but the few I solved seemed like nice puzzles. I try to avoid trial and error when possible but barely got started. Regular killer took almost 40 minutes. Fumbled with kropki about 15 minutes, got nowhere. Couldn't even begin little killer. Lost interest, walked away and made a cup of coffee...I'll save the rest for a rainy Saturday sometime.
romanm44
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-10 12:41 AM (#28220 - in reply to #28158) (#28220) Top




Posts: 3

Location: Canada
It appears to me that there are 2 solutions to 09 Odd Even Count using the digits 1, 2, 3, 5, 7, 9. The corner circles are 3s and the interior circles are 7s. The two solutions would arise by swapping the 1s and 2s in columns three and six.

Have I missed something here?
prasanna16391
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-10 3:03 AM (#28221 - in reply to #28220) (#28221) Top


PR 2020 (Evergreens) Author

Posts: 1354
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Location: India
romanm44 - 2020-05-10 12:41 AM

It appears to me that there are 2 solutions to 09 Odd Even Count using the digits 1, 2, 3, 5, 7, 9. The corner circles are 3s and the interior circles are 7s. The two solutions would arise by swapping the 1s and 2s in columns three and six.

Have I missed something here?


You may be missing the rule that all circles are marked, meaning that no digit can follow the count properties if it isn't in a circle.
romanm44
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-10 4:25 AM (#28222 - in reply to #28158) (#28222) Top




Posts: 3

Location: Canada
Thanks Prasanna! I had forgotten thank requirement. That eliminates one of the solutions.
TiiT
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-10 7:59 PM (#28223 - in reply to #28158) (#28223) Top




Posts: 122
10020
Location: Estonia
I think it's a very cool competition. I really enjoyed ! But I also agree this guessing part many have mentioned here before me.
tamz29
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-10 8:02 PM (#28224 - in reply to #28158) (#28224) Top




Posts: 182
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Location: Thailand
Thanks for a nice change from the PRs and SMs, Rakesh.
I didn't pay attention to the IB's Sequences example and lost some time to figure out +0 is a valid arithmetic progression.
You could see a lot of clever intended paths - showing how meticulously these were made.
Unfortunately, as Byron noted, the 6x6 nature made this test prone to guessing for one to solve as many grids as possible in the 90 minutes.

Good fun nonetheless. Thanks again!
rakesh_rai
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-10 11:32 PM (#28225 - in reply to #28214) (#28225) Top



Mean Minis (2020) Author

Posts: 749
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Location: India
ByronosaurusRex - 2020-05-09 5:33 AM

...I should mention that Sequence felt particularly overvalued -- I skipped past it at first because I thought I was a bit short on time to risk it, then came back later and quickly steamrolled through the full solution path in just over 3 minutes. Its difficulty is almost entirely contained in the "same digit repeated is an arithmetic progression" a-ha moment, which feels like the puzzling equivalent of a trick question; to its credit, the puzzle made eliminating all other options for that line incredibly efficient, so it was probably the best possible execution of that trick, but 9 points still felt like too great a reward for spotting it so quickly.
For every high-pointer, there would be some participants who do it in a quicker than expected time. For sequence, based on the observations so far, participants have indeed taken some time before realizing that 3-3-3-3 sequence as a possibility. Since 1 and 2 are not possible on the longer line, 3456 seems a more natural sequence everyone would go for, and then reach a contradiction. I agree it is not a complex deduction but still takes time somewhere.
danielbabu
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-13 3:01 PM (#28226 - in reply to #28158) (#28226) Top




Posts: 1

Location: india
Password is sent by mail?
kishy72
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-13 6:49 PM (#28227 - in reply to #28158) (#28227) Top


SM 2020 (Math) Author

Posts: 381
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Location: india
Thanks for a wonderful contest Rakesh .Monthly contests are a rarity nowadays and it was a pleasant sight to see a sudoku contest aside from the routine of SM & PRs. This contest made me reminescent of ISC 2016?! wherein Round 4 (authored by Deb)had 6x6 sudokus with unknown list of digits in which I scored 43 and you 133 (if I am not wrong and my memory is good.I am unable to get the result list for the same to verify) and you edged ahead of me to podium.

I would be curious to know your inspiration for writing this test and whether you got the idea by the above mentioned round.About the contest itself, the sudokus were definitely on the harder side and will be extremely fun to solve as one-offs without contest time constraints or pressure. In the contest, I had to guess on most but I did find logic in a few and they were very interesting. Thanks again ! Hope we get to see more monthly contests in LMI !
Administrator
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-13 6:56 PM (#28228 - in reply to #28226) (#28228) Top


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Location: India
danielbabu - 2020-05-13 3:01 PM

Password is sent by mail?

It is displayed on the screen once you start the contest. It seems you already took the test. So you would be knowing this already.
Anu G
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-13 10:59 PM (#28229 - in reply to #28158) (#28229) Top




Posts: 9

Location: India
Very interesting set of puzzles. It was certainly very challenging trying to find out the digits by solving , but made it more fun too. i wish I was less sleepy and had a printer since I took time solving online. Thanks for a very innovative contest.
mstang
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-14 12:58 AM (#28230 - in reply to #28158) (#28230) Top





Posts: 63
202020
Location: USA
Those puzzles were really hard, but very fun! I wish I had had more time, but I enjoyed solving what I could in the time allotted. Thanks very much Rakesh!
harmeet
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-14 7:52 AM (#28231 - in reply to #28158) (#28231) Top


SM 2020 (Converse and Odd Even) Author

Posts: 66
202020
Location: India
Thanks Rakesh for Mean Minis! They were a wonderful set of moderate to hard puzzles with very interesting solving paths. Thoroughly enjoyed.
Administrator
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-14 9:17 AM (#28232 - in reply to #28231) (#28232) Top


2000500100100100202020
Location: India
The Solution Booklet is now available here.
rakesh_rai
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-15 7:12 PM (#28236 - in reply to #28232) (#28236) Top



Mean Minis (2020) Author

Posts: 749
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Location: India
Congratulations to Nikola Zivanovic for winning this contest by a mile. Congratulations to Endo Ken, Prasanna Seshadri, Tiit Vunk, Salih Alan and Tantan Dai for completing all 18 grids inside 70 minutes. In fact, all 15 finishers did very well. Amongst competitors from India, Good performances by Kishore, Pranav, Harmeet and Kartik.

Thanks Rob, Byron, Ashish, Bob, Tiit, Tawan, Kishore, Anu G, Michael and Harmeet for sharing feedback on the test! Also, thanks to all the 246 participants for trying out this test.

The concept of the test was indeed taken from one of the rounds in ISC 2016. I had liked this concept very much at that time.

I knew before the test that there could be a fair amount of guesswork in play - owing to the moderate/hard logic and 6x6 nature. That is one reason I increased the number of grids from (initially planned) 15 to 18. After having watched live streams of Puzzle GP and Sudoku GP finals in recent years, I can say that every contest involves some amount of guesswork. And, even when one says he/she guessed, I think it is a combinaton of x% logic and y% guess. And, as long as x is a decent number, it is fine. At the same time, I was not too worried about this aspect - specifically I did not think about things like "Can this one be resolved by guessing easily?" while creating the grids.

I am not surprised that Inequality Sudoku was solved the most. That would probably be a first for this type, as this is a not-so-popular variant in general. Little Killer and Odd Even Count had the least correct submissions. However, both fared exactly opposite of each other in terms of accuracy of submissions. Expectedly, there were many submission errors in Odd Even Count Sudoku due to the 12-21 twist in the end. No one made an error in LK submission. In the test, I would have liked to include mini classic sudoku and more common variants like diagonal, palindrome, extra region, etc. But they would have needed all six digits to be provided, so they were excluded.

Based on the comments, there may be a second edition of Mean Minis coming soon - with a different set of 18 variants.
IHNN
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-16 12:50 AM (#28237 - in reply to #28158) (#28237) Top




Posts: 1

Location: USA
I wasn't able to find time to attempt this during the contest, but I've worked through the full set on my own time since. I usually sit out on sudoku contests, but the theme here piqued my interest enough and I'm very glad I solved these. My favorite paths were the Little Killer and X Sums, though I also loved placing all copies of an unknown digit in the Kropki, twice, before deducing the digit set.

Wonderful puzzles across the board though, thanks for creating them!
sstackho
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-16 7:18 AM (#28238 - in reply to #28230) (#28238) Top




Posts: 11

Location: Canada
mstang - 2020-05-13 2:58 PM

Those puzzles were really hard, but very fun!


Same sentiment from me. Very interesting puzzles to solve! Some took me a reallllly long time to solve though...
rakesh_rai
Subject: Re: Mean Minis - LMI May Monthly Sudoku Test - 8th to 13th May 2020 @ 2020-05-17 1:08 AM (#28243 - in reply to #28238) (#28243) Top



Mean Minis (2020) Author

Posts: 749
5001001002020
Location: India
Thanks Jeffrey and SS!