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Prime Exotica - LMI Jan 2011 Sudoku Test108 posts • Page 4 of 5 • 1 2 3 4 5
@ 2011-01-25 2:29 PM (#3291 - in reply to #3146) (#3291) Top

David McNeill



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David McNeill posted @ 2011-01-25 2:29 PM

For the record, I had prepared a list as well. I didn't have Rishi's lovely 45, 69 insight. However, it didn't take too long to find the options which fitted. About the same length of time as it took for my printer to print out the test. There are 2 options missing from Rishi's list i.e 4x39=156 and 7x52=364. Just as well these weren't needed!

Enjoyed the contest very much. Thanks Rakesh and LMI. I also must confess to having a list of primes and the possible combinations of 4 digits totalling 17, which makes me a triple cheat!

David McNeill.
@ 2011-01-25 2:33 PM (#3292 - in reply to #3291) (#3292) Top

purifire




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purifire posted @ 2011-01-25 2:33 PM

David McNeill - 2011-01-25 2:29 PM

For the record, I had prepared a list as well. I didn't have Rishi's lovely 45, 69 insight. However, it didn't take too long to find the options which fitted. About the same length of time as it took for my printer to print out the test. There are 2 options missing from Rishi's list i.e 4x39=156 and 7x52=364. Just as well these weren't needed!

Enjoyed the contest very much. Thanks Rakesh and LMI. I also must confess to having a list of primes and the possible combinations of 4 digits totalling 17, which makes me a triple cheat!

David McNeill.


Thanks David, I too had the list of primes with me... I just didnt have the combinations of 17 ready

Rishi
@ 2011-01-25 8:04 PM (#3300 - in reply to #3146) (#3300) Top

RJH0723



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RJH0723 posted @ 2011-01-25 8:04 PM

Thx guys! I attempted it again with the list, and got it right away. I should try "cheat sheeting" next time.
@ 2011-01-25 8:13 PM (#3301 - in reply to #3300) (#3301) Top

rakesh_rai




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rakesh_rai posted @ 2011-01-25 8:13 PM

Since we are discussing cheat sheets, another candidate was numerologidoku. An excel worksheet can easily save 3-4 minutes of calculation time - converting the names into clue numbers. Did anyone use this cheat sheet too?
@ 2011-01-25 8:40 PM (#3302 - in reply to #3301) (#3302) Top

akash.doulani



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akash.doulani posted @ 2011-01-25 8:40 PM

this was the puzzle where i had got stuck at the end. got it wrong somewhere and after 7 min realised that i had goofed up . and then in our locality people are celebrating netaji's birhday and republic day . and so the local club turned on loudspeakers . the loudspeakers are still on and will be on till tomorrow.
@ 2011-01-25 9:12 PM (#3303 - in reply to #3302) (#3303) Top

rakesh_rai




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rakesh_rai posted @ 2011-01-25 9:12 PM

Those who forgot to rate the puzzles or did not have time during the test can still rate the puzzles by visiting the test link.
@ 2011-01-25 9:35 PM (#3304 - in reply to #3301) (#3304) Top

drsteve



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drsteve posted @ 2011-01-25 9:35 PM

rakesh_rai - 2011-01-25 3:13 PM

Since we are discussing cheat sheets, another candidate was numerologidoku. An excel worksheet can easily save 3-4 minutes of calculation time - converting the names into clue numbers. Did anyone use this cheat sheet too?


I thought this would be a step too far - too much like using a calculator for the product sudoku. I went into the test with WPC rules in my head - anything written down was OK, but actually using a computer to speed up calculations would be frowned upon.
@ 2011-01-25 9:59 PM (#3305 - in reply to #3304) (#3305) Top

motris



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motris posted @ 2011-01-25 9:59 PM

Wow. This forum went crazy in just the few short hours I was asleep. Now people are comparing (and posting) their cheat sheets to see who was better prepared? Seriously?

I personally disliked most of the puzzles that seemed to require extra/outside knowledge. Numerologidoku, for example, had no extra value to me for doing the addition. The puzzle itself solved fine once you had the sums, but I didn't feel doing the math added much value to the experience. In just the case of Kombinance, where the 9 groups should be obvious from the example (I saw no other way to finish that example than to make the connection of total # of groups), do I think - in accord with off-line tests - that "notes" were appropriate to bring in. But then my personal feelings aren't relevant so much as the author's goals and the test instructions themselves. There, no guidance was given - on the use of a calculator or a spreadsheet or printed notes. And the prime list link in the forum wasn't removed or turned away so as to say "do not bring such a thing into a test". So I think after the test it is worth a reevaluation of what the ground rules are for such a test and what should/should not be allowed. That, or simply choose puzzles that don't need extra information that doesn't add a lot of value. My favorite puzzles in this test, like the Rossini, simply solved as beautiful sudoku.
@ 2011-01-25 10:01 PM (#3306 - in reply to #3284) (#3306) Top

channa



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channa posted @ 2011-01-25 10:01 PM

@ Rakesh
Hehe..dint realise that...this is first time i am attempting..thot prob with software or something...BTW, nice puzzleset...ruing the fact that i couldn't stumble upon this website long before....

How many ppl actually rote this test?? ..

Edited by channa 2011-01-25 10:02 PM
@ 2011-01-25 11:40 PM (#3307 - in reply to #3288) (#3307) Top

rakesh_rai




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rakesh_rai posted @ 2011-01-25 11:40 PM

RJH0723 - 2011-01-25 5:40 AM
Just wondering, how did u guys approach the multitab sudoku?
Thanks Rishi and David for sharing your approach.

Here's the approach which I had intended. Of course, there could be better and quicker approaches. But this is what I had thought of. Do let me know if any step is not clear.

Diagram A: One out of R9C4, R9C5 and R9C6 has to be a 1. And the first two cannot be a 1. So R9C6=1. Then R2C4, R1C8, and R5C9 also must be 1. Now in C1 and C5, there are two possibilities for 1 in R4 and R6. We must realize that R4C1 cannot be 1 as then we cannot get a three digit number after multiplication. So R6C1 and R4C5 are 1s.

Diagram B: Lets consider the last row. 2 must be one of the cells R9C4 or R9C5. This means R9C8 must be 6 (it cannot be 8). As we got 1 and 6 in the three digit number, it is not difficult to find the remaining numbers.

Diagram C: Now look at the last column. 5 goes into R6C9. Again, as we have got two numbers in the three digit number, the rest is easy to get.

Diagram D: R6C2=2. In column 1, 7 can be only in R4C1 (it cannot be in R3C1, because then multiplication will fail), which means R3C1=2, and the rest of column 1 falls through.After that, its normal sudoku rules and the top row also falls through.



(multitab.png)



Attachments
----------------
Attachments multitab.png (54KB - 2 downloads)
@ 2011-01-25 11:47 PM (#3308 - in reply to #3306) (#3308) Top

rakesh_rai




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rakesh_rai posted @ 2011-01-25 11:47 PM

channa - 2011-01-25 10:01 PM@ RakeshHehe..dint realise that...this is first time i am attempting..thot prob with software or something...BTW, nice puzzleset...ruing the fact that i couldn't stumble upon this website long before.... How many ppl actually rote this test?? ..
I think you meant "wrote". 186 people started the test and 144 submitted at least one correct answer.
@ 2011-01-26 1:12 AM (#3309 - in reply to #3305) (#3309) Top

rakesh_rai




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rakesh_rai posted @ 2011-01-26 1:12 AM

motris - 2011-01-25 9:59 PM

Now people are comparing (and posting) their cheat sheets to see who was better prepared?
Congratulations for finishing 1st in the test, and thanks for your detailed feedback.

I don't think better preparation is wrong. But the use of cheat sheets - probably not fair - let the individuals decide. Since (this time) it was not explicitly mentioned that x or y cannot be used, they were not wrong. I think this is one positive aspect from this test - in future, we may need to firm up the rules on this aspect as well, not just the puzzles.

I personally disliked most of the puzzles that seemed to require extra/outside knowledge.
However, in my opinion, there were no such puzzles which required extra/outside knowhow. All knowledge needed was in the instructions. Some basic rules for prime numbers, multiplication, addition was all that was needed.
Numerologidoku, for example, had no extra value to me for doing the addition. The puzzle itself solved fine once you had the sums, but I didn't feel doing the math added much value to the experience.
OK. Perhaps, that part could have been avoided
...And the prime list link in the forum wasn't removed or turned away so as to say "do not bring such a thing into a test".
The puzzle was not much dependent on a list - It was easily solvable without needing that list, and probably faster too.

And, thanks for sharing your personal feelings. While solving, as you rightly mentioned, they may be less relevant than the test instructions, but definitely they can provide us with concrete ideas for improvements in future.
@ 2011-01-26 1:15 AM (#3310 - in reply to #3304) (#3310) Top

rakesh_rai




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rakesh_rai posted @ 2011-01-26 1:15 AM

drsteve - 2011-01-25 9:35 PM
rakesh_rai - 2011-01-25 3:13 PMSince we are discussing cheat sheets, another candidate was numerologidoku. An excel worksheet can easily save 3-4 minutes of calculation time - converting the names into clue numbers. Did anyone use this cheat sheet too?
I thought this would be a step too far - too much like using a calculator for the product sudoku...
Exactly. This was meant to be a comment.
@ 2011-01-26 7:32 AM (#3311 - in reply to #3309) (#3311) Top

debmohanty




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debmohanty posted @ 2011-01-26 7:32 AM

rakesh_rai - 2011-01-26 1:12 AM

motris - 2011-01-25 9:59 PM

Now people are comparing (and posting) their cheat sheets to see who was better prepared?
Congratulations for finishing 1st in the test, and thanks for your detailed feedback.

I don't think better preparation is wrong. But the use of cheat sheets - let the individuals decide. Since (this time) it was not explicitly mentioned that x or y cannot be used, they were not wrong. I think this is one positive aspect from this test - in future, we may need to firm up the rules on this aspect as well, not just the puzzles.


I'm not sure if we should leave it to individuals to decide. The problem is that "not everyone gets same amount of time to prepare for the test".
This is no national / world championship, so we can't blame players for not spending enough time for preparing.

The simplest solution, copied from motris's post, is to "Choose puzzles that don't need extra information that doesn't add a lot of value"
@ 2011-01-26 10:14 AM (#3313 - in reply to #3311) (#3313) Top

vopani



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vopani posted @ 2011-01-26 10:14 AM

Wow! I had prepared a 'cheat sheet' for Numerologidoku where just entering the alphabets gets you the sum directly in excel (just like Rakesh mentioned).
The irony is, I did not use the sheet with the view of feeling guilty later on ;-) I mean, something made me feel unfair, so I calculated the sums manually. Best part is, I made a mistake in calculating one sum. And I was lucky enough to find out the error quickly.

I too agree that such puzzles should be avoided or the extra information should be given.
@ 2011-01-26 3:12 PM (#3316 - in reply to #3146) (#3316) Top

zalak



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zalak posted @ 2011-01-26 3:12 PM

Rakesh, thanks for such a wonderful test, I thoroughly enjoyed all the puzzles. I couldnt solve them during the test but I tried them after the test.. I must say I was stumped by the Rossini, and got the logic just as I had some 2 minutes left, but in the end, it did make me smile.. beautiful logic!

Well, about the cheat sheets, I wanted to make one for Kombinance, Multitab, Numerologidoku and Prime number but somehow was not convinced about doing that.. thought it would only be fair to take the test like it was an offline test. But since it was not mentioned in the rules, it was rightly left to the individuals.. But from next time onwards, it would be good to either mention that in the rules or give the clues, so all the participants are at the same level..
@ 2011-01-26 5:48 PM (#3319 - in reply to #3316) (#3319) Top

rakesh_rai




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rakesh_rai posted @ 2011-01-26 5:48 PM

Nikola - 2011-01-25 1:20 PM

Lovely set of the puzzles. Great job, Rakesh! I prefer concept of DNA sudoku with a lot of clues.
David McNeill - 2011-01-25 2:29 PM

Enjoyed the contest very much. Thanks Rakesh and LMI.
channa - 2011-01-25 10:01 PM

BTW, nice puzzleset...ruing the fact that i couldn't stumble upon this website long before....
zalak - 2011-01-26 3:12 PM

Rakesh, thanks for such a wonderful test, I thoroughly enjoyed all the puzzles... I must say I was stumped by the Rossini, and got the logic just as I had some 2 minutes left, but in the end, it did make me smile.. beautiful logic!
@ 2011-01-27 9:42 AM (#3321 - in reply to #3192) (#3321) Top

Administrator



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Administrator posted @ 2011-01-27 9:42 AM

rakesh_rai - 2011-01-17 11:43 AM

A feature being tried out this time is that of "anonymous ratings". On the score page, the average rating and number of solvers who rated will still be visible. But A cannot see ratings given by B (and vice-versa).

It could just be a coincidence, but this test got maximum number of ratings per puzzle since the introduction of ratings in mock13.
On an average, each puzzle received 14.77 number of ratings in this test.

Here is how puzzles in other tests (top 5 listed) were rated.
14.77 | Prime Exotica
14.56 | Sudoku Mock Test 15
12.44 | EverGreens II
12.27 | 20/10 Puzzle Decathlon
12.17 | Master Mind Twins

Although ratings are not the most important thing in a test, we would like to believe that most players like the ratings this way (i.e. to be anonymous) and we would continue this in future tests.
@ 2011-01-27 6:34 PM (#3324 - in reply to #3309) (#3324) Top

Ours brun




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Ours brun posted @ 2011-01-27 6:34 PM

rakesh_rai

motris

I personally disliked most of the puzzles that seemed to require extra/outside knowledge.

However, in my opinion, there were no such puzzles which required extra/outside knowhow. All knowledge needed was in the instructions. Some basic rules for prime numbers, multiplication, addition was all that was needed.

I agree with motris; as Rakesh said, in the current case all puzzles were solvable without outside help. However, in some cases, "cheat sheets" could certainly allow to save a non-negligeable amount of time ; this, I dislike. But it is not really a specificity of this particular test ; when solving killer sudoku, using a sheet with all the possible combinations of digits can also prove useful - and lots of people use such a sheet every time they solve a killer sudoku. The important point for me is to clearly mention what is allowed, and what isn't (the ideal being for me : "no exterior help, of any kind, is allowed").

rakesh_rai

motris

...And the prime list link in the forum wasn't removed or turned away so as to say "do not bring such a thing into a test".

The puzzle was not much dependent on a list - It was easily solvable without needing that list, and probably faster too.

Which is why I liked the puzzle, despite being primarily reticent to the idea. No need to know - or search for - big primes to solve it. By the way, nice job on this particular puzzle.

rakesh_rai (concerning multitab sudoku)
Here's the approach which I had intended. Of course, there could be better and quicker approaches. But this is what I had thought of.

I solved this puzzle once the competition was over, and did nearly exactly the way you did.
@ 2011-01-27 7:09 PM (#3325 - in reply to #3146) (#3325) Top

lucarabino



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lucarabino posted @ 2011-01-27 7:09 PM

Hi. I found that ROSSINI and TENNISDOKU were not able to be solved, because in ROSSINI double arrows were not visible and in TENNISDOKU only few scores were visible (in application and in the pdf). Why??? How could be solved by the winners?
@ 2011-01-27 7:26 PM (#3326 - in reply to #3325) (#3326) Top

Ours brun




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Ours brun posted @ 2011-01-27 7:26 PM

Hi,

In both cases you need to be very careful about the sentence beginning like this : "If there is no..."

To be clear : on rossini sudoku, there are no arrows because, on this particular puzzle, digits are never in strictly ascending or descending order. This is a very useful information.
On tennisdoku, where there isn't a tennis ball the score can't be one of a tennis match. For example, if there is no ball touching a "4", there can't be a "6" in the adjacent cells.

Does it help you ?
@ 2011-01-27 7:39 PM (#3327 - in reply to #3146) (#3327) Top

Ours brun




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Ours brun posted @ 2011-01-27 7:39 PM

A few more help, if needed :

! SPOILER !


Let's have a look at Rossini sudoku :

Spoiler: show

There is no arrow at the right of 5th row. This means that the 3 corresponding digits cannot be in either ascending or descending order. We already have 5>1 so the cell located between those two must contain a digit which is either smaller than 1 (impossible) or bigger than 5. This digit has to be 8...


Now look at Tennisdoku :

Spoiler: show

The 5th row is again particularly useful. 2, 6, 8 and 9 remain to be placed. There is a ball touching the 3; the only possible score with a 3 is 6-3, so let's put a 6 in R5C2.
Then : on the left edge of this cell, there is no ball. So, R5C1 and R5C2 (6) cannot form a valid score. 2, 8 and 9 remain to be placed. 2-6 would be a valid score, as well as 8-6. So, there must be a 9 in R5C1...

@ 2011-01-27 8:49 PM (#3329 - in reply to #3325) (#3329) Top

rakesh_rai




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rakesh_rai posted @ 2011-01-27 8:49 PM

lucarabino - 2011-01-27 7:09 PM

...in TENNISDOKU only few scores were visible (in application and in the pdf)...
Thanks Ours brun.

lucarabino: Yes. In Tennisdoku (as also in Kid sudoku), all scores were not given as clues, as then it would have become too easy. But the grid was solvable with the given clues as the tennis balls provided enough hints. And 59 solvers did solve it.

@ 2011-01-27 8:51 PM (#3330 - in reply to #3146) (#3330) Top

Administrator



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Administrator posted @ 2011-01-27 8:51 PM

Solution Booklet here
@ 2011-01-27 8:56 PM (#3331 - in reply to #3146) (#3331) Top

Ours brun




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Ours brun posted @ 2011-01-27 8:56 PM

Thanks for having modified my post, I didn't know that there was a "spoiler tag".
Prime Exotica - LMI Jan 2011 Sudoku Test108 posts • Page 4 of 5 • 1 2 3 4 5
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