2 players (zorko and nikola) got all the Match Makers correct. [ Interesting that zorko has submitted only one classic ]
janoslaw got 7 correct.
4 more got 6 correct.

As many as 29 players got all Classics correct.

Check here for the split - http://logicmastersindia.com/M201008S2/ScoreSplit.asp

Thanks Deb. So, most participants did not get enough time for matchmakers as only 56 participants got points as against 101 in classics.The testing of the sudokus and the duration of the test could have been better designed. For example, diagonal, touchy, and no three odd/even could have had more points than the rest of the variants. Also, having the test for 2.5 hours is not correct (its too long). We could have dropped one classic and one variation perhaps for a 2 hr test.

well..when i completed the classics i found that i had 6 mins left for the variants. :P, i am really slow , i don't know what the standard advanced techniques are...is there some place where i can learn or in that case even the basic ones :P

for some players, Qixi rank is displayed as Qixi Score. This will be fixed soon. Sorry for this inadvertent miss.
thanks to luckypunk for bringing it to our notice.

Wonderful sudoku test, congratulations for organizers and all toppers! Classic sudokus are my old complaint, but I think this time I chose the wrong tactics. I have the same number of performed puzzles as Jakub and Thomas, and look at the difference! I solved all matchmaker in about 85 minutes and the rest of time did only 6 classics.

Thanks to Lin Ming Fang.. very logical and definite clues to figure out the match makers :-)

To luckypunk: you can search "intersection, pairs, x-wing" by google.
To rakesh_rai: diagonal, touchy and no 3 odd/even in line are most difficult in variants part, both the puzzle itself and determining the rule. But if one solved as the order we show, he can complete at least 5/8.
Are there someone need help with the puzzles? Please let us know. All puzzles can be solved by logic.

yo thnxs min..got many links...will improve now..

MinFang Lin: If you could give a few starting steps on the diagonal (without trial/error), that'd be helpful. I am stuck at the beginning itself

Deb told me about this, maybe your question is many players' question.
i will show you later...please give me some time to do it.
Are there any other questions?

Thanks for this wonderful tournament, I've just finished to solve grids (I redo the entire relay as it was a catastroph during Test).

About my test:

I did wonderful stupid mistakes on part I (relay): Bad report of relay numbers between puzzle 1 and puzzle 2 (I lost about 10 minutes at the very beginning of the test ). On another relay puzzle, I copy numbers on cells with grey circles instead of cells with white circles .
After 1h10 and finally 7 relay puzzles laboriously finished, I begin "match maker part", it was fun and I manage to solve 5 grids in about 35 minutes (with one mistype - a single digit - on the antiknight), which is quite good, I think. Then during the last minutes I try to solve the last relay puzzle, with no success .

After the test, I finish "match maker part". It was really fun and very good grids. Diagonal was very tough, perhaps too much for this 2h tournament.

grids 17 were fun, too !

I think, inversely to "sampler platter", it was a little bit too difficult for a 2h tournament. Relay are always a trap because you can't do mistakes, otherwise it spreads on next puzzle and you are blocked on every other grids.
Perhaps a 6-grids relay and easier diagonal grid on match maker would have been more balanced for a 2h tournament.

However, it was a very good test with very good grids ! Thanks !

Fred

Transfer square No.16 (row 4, column 5 in the diaonal puzzle) has only possible digits 2,5,7. Look at final twin puzzle, transfer clues 1 and 14 are digits 7 and 2. So transfer clue 16 has to be 5 and transfer clue 15 is 8 (only possible 8 in irregular shape)

When you add these two digits, diagonal puzzle is easy to complete

Of course, this trick is possible only if you already solve some others matchmaker puzzles before diagonal.

Edited by Gotroch 2010-08-17 7:21 PM

there is much of a tie in the standings. Should they not be classified according to the time resolution?

Good point Fred. Not sure if we should change anything for this test, because we didn't annouce anything before the test. But in future we must introduce tie-breaker rules.

If others think that we should break the ties based on submission time, we can try to that for this test itself.

!

And with that post, this thread becomes the thread-with-most-posts at LMI forum

The first step of diagonal:

See D\ only two place can be 7 (r1c1 and r5c5), so r1c9 and r9c1 can't be 7.
Then check D/ only one cell can be 7, it's r5c5.

The technique is called crossover.
You can learn it from http://www.sudopedia.org/wiki/Crossover
or search it by google.
Any other question?

Thanks Min. After that crossover step, it does indeed solve out logically.

It will become easy buddy when you spend some time and give the total time till the submission of last answer in minutes instead of time of submission.....

I am happy to see others found the Diagonal to be difficult. I spent many minutes trying to find that first number and simply couldn't find it for quite some time! But once I did I was able to make some progress -- it still was not easy from that point forward however.

The crossover step is perfectly legitimate, and I think this is one of the best Diagonal puzzles I've ever solved. Like many others on the test, it is 5-star.

When it comes to ties -- I'm reminded of the 2009 Semifinals where a time-based tiebreaker for incomplete solutions was used, and it did not seem to work out very fairly. If two great solvers did exactly the same puzzles and didn't finish, maybe they both deserve the credit?

I was not in Zilina, but I think it's a very different situation. Here you have not to choose stop playing before end of time. You can submit answer before the end of test and continue to try to solve last puzzles.
if two great solver who didn't finish have same amount of points, but one reached it after 1h45 and the second after 1h58, it seems fair to me that the first one appears first in the ranking.
I don't say it's not fair now, it's just a detail, not very important for the LMI tests.

For diagonal sudoku, I've quite often found visualizing placements along the extra constraint, such as at WSC2 Prague Final and here, incredibly valuable. Indeed, so much so that I specifically take time in my solving routine to think about the immediate consequences of any number much more so than any other variant, kind of like a Nishio where you see if a few placements down the way you can possibly place all 9 instances of a digit with exactly 1 on each diagonal. This is generally not useful on classics, since a lot of either/or choices in empty space don't do much, but on diagonals the difference between two options is often digits on 0 diagonals, or 2 digits on a single diagonal, or other results that can't work. So I would not say I was looking for a crossover here (I'm not familiar with the term actually). But one of the first things I did was convince myself R1C1 couldn't be a 4. Similar thinking next showed me the 7 couldn't be in that spot either, so one or the other had to be in the center and that became obvious as the 7 (leaving R2C2 for the 4). That's just how my mind approaches diagonals. And I guess I suspected by then, since no Matchmaker could have any digits placed without identifying the extra constraint, that some cool diagonal cycle was certainly the way to start the puzzle here.

Re: Zilina and tiebreaking - the fundamental problem in Slovakia was not grading playoff puzzles along the way, as has been done by virtually all other WPC/WSC hosts in my time competing. Having 36 semifinalists in a single heat made this impractical, but that's a whole other discussion about good/bad planning decisions.

Within your scoring system, you have time-stamps for when a solver has submitted their last "correct" solution which makes it clear when, at a particular score, solvers have reached that point. Imagine a close test that has a grossly undervalued puzzle that is a particular stumper for many people. Maybe no one solves it, maybe someone does. But if 3-4 people are tied without just that puzzle, then the first to have everything but that one solved is a very fair tiebreaker to use. Here, Jakub and I are still pretty close to tied within 2 minutes (not a terribly meaningful amount of time to separate us, but I'd pip him out), but anything approaching a 10-15 minute separation case, as was the case in Zilina, would have let a large number of tied solvers be separated fairly. There, many solvers reached 3 of 4 puzzles done with 10+ minutes left to attempt the last stumper. Slower solvers who eventually reached 3 of 4 puzzles done with 2 minutes on the clock just said done and turned in their papers since they had no chance to finish the last puzzle. Since you'll know when solvers get to a particular score, its not a comparable situation.

As one of the most vocal critics of competition rules, I'd be completely satisfied with using the last submitted time as a sorting method with granularity at 1 minute levels pretty reasonable to view as a tie break.

Edited by motris 2010-08-18 4:02 AM

Using the timestamp of the final correct puzzle is certainly not an unfair way to break ties. I don't think anybody would have a claim that they deserved to be ranked higher *because* they didn't submit until after the other person.

But when there are still puzzles yet to be solved, there are other reasons why someone could be "ahead" (which is to say they solved all but one puzzle more quickly than anyone else). If you are done with *all* your puzzles (and you solved on paper), then you immediately submit them electronically. But if you have one puzzle left...maybe you spend as much time as you think you can on that puzzle? Maybe you leave five minutes at the end of the test to transfer your paper solutions over to the website, so while it seems like you just then solved the second-to-last puzzle, really you reached that point many minutes before and were just stuck.

If this tiebreaker were adopted, since players from all over the world value LMI tests as the top monthly sudoku competitions, they would naturally want to rank as high as possible. But I think that would mean they would go from paper-to-computer-to-paper-to-computer...over and over near the end of the testing period, which is just when they need to focus the most on solving. I think that's needlessly inefficient and doesn't really reflect who's better.

I would prefer weighting the puzzles themselves *slightly* differently. Give an extra 0.1 to the hardest puzzle, 0.01 to the second-hardest, 0.001 to the third-hardest...and so on. So if you match someone's point total, maybe these fractional points will provide the difference. Or, in the case where nobody finishes the test, let the top performers stay tied.