Logic Masters India announces July 2011 Puzzle Test #1 — Nikoli Selection

Author : TOM “detuned” COLLYER

Dates : 9^th and 10^th July

Length : 90 minutes

IB and Submission Link : here

Just a quick answer key question. For shikaku, does this also have the same rule as fillomino, where you only type the last digit if a multidigit clue is in the row or column? I think this would help make the answer keys consistent.

Yes, I agree that it will be consistent. It is probably not necessary for the actual puzzle in the test.

We are discussing about having consistent answer keys across puzzle tests.
Please check this sub-forum and contribute.

just to clarify,
in the instruction it is mentioned that "It is highly recommended that you do not attempt solving the marathon
puzzles before correctly solving the first part of the test!"

is it like we have to first complete that 16 puzzles then only the points for marathon puzzle is valid.

I assume it means that solving 3 normal puzzles for 50 points will most likely cost you less time than solving one marathon puzzle for 50 points. So it's more point effective to solve all normal puzzles before attempting the marathon ones. Also probably more fun as working on a puzzle for a long time and eventually not finishing in time can be frustrating. You can check the previous nikoli selection, to see the size of the marathon puzzles, they are somewhat intimidating. I'm assuming they will be similar this year.

I have a question about the time bonus as it's mentioned after the first 16 puzzles. Does the time bonus count after the last correct submission from the first 16 or in total? Say someone finishes the first 16 in 65 minutes and another in 70 minutes, but the first solver finishes a marathon puzzle at 89 minutes, while the second solver finishes the marathon at 88 minutes. In this scenario, which player scores most points?

Swaroop,

Para has put it very nicely. You should solve marathon puzzles only after completing all Main section puzzles.

The "point value" of a main puzzle > The "point value" of a marathon puzzle > The "point value" of time bonus
[ "Point Value" is points you get for spending a minute ]
To secure more points, you should be doing the main puzzles first.

Regarding marathon puzzle sizes, they will be almost similar size as last year's.

Bonus points will be given after one submits all 16 main puzzles correctly. So, the first player in your example will get 5 more points than second player.

Essentially this test is about the main puzzles. But again these are puzzle types where solving time difference between top players and average players will be huge. So the marathon puzzles serve as bonus puzzles. Instead of giving significant bonus points for completing earlier, top players are challenged to solve the marathon puzzles to earn those points.

Tom, correct me if I'm wrong, and please share your perspective too.


If top players see this as a problem, they should post here / let us know. It is much much easier to fix a bonus system before the test starts.

Deb is essentially right, I expect to see some very quick times for the main section. I also expect that no-one will get 3 marathon puzzles, although I'll be surprised if there aren't a couple who get 1 and *maybe* even 2 of them. As Deb says, it gives top solvers a challenge to earn some bigger bonuses.

At any rate, there will be a small points-per-minute sub-bonus for anyone who finishes the main section, which will still serve as a tie-breaker to those who can finish but won't have time to get a marathon done. I don't expect this scenario will apply to many people.

I suppose the best way to look at things is this: very few people will get the whole set done in time. The marathon puzzles (OK not quite nikoli giants sized, but I have to compromise with printing and so on) should then be seen as something extra to keep you occupied for a few days after the test, to be enoyed at your own leisure without the pressures of against-the-clock solving.

Except that I expect for the usual suspects that getting that second marathon done will be the entirety of the podium decision since the general time bonus is much smaller. I mostly enjoyed the puzzles last time but had to say the marathon bonus system was not my favorite choice. We'll see how it works out this time.

I'd be highly surprised that even if anyone gets two out, that they'd not be one of the fastest solvers of the main set anyway. I don't think this works out to any plausible scenario as being unfair to any of the top contenders. The time bonus acts as the main tie breaker - but if anyone can get two of these puzzles out then in my eyes they are certainly deserving of finishing ahead of someone who only finishes one (or none), even if there's a small difference between them in the main section.

I agree this system is a little quirky, but I think it's an interesting idea and the best way to see if it really works or not is to give it a go. We've seen some really good innovations come out of past LMI tests.

Edited by detuned 2011-07-05 6:35 PM

There will be 2 small changes to the submission system this time.

1) The timer and password will be shown left to the text boxes.
Serkan had suggested this earlier so that players won't have to scroll to see the timer.
See image below.

2) When only one of the two required field are entered, the other field will be highlighted.
It was suggested by motris, and it had been pending for a long time. See image below for FILLOMINO puzzle.

I agree that we should see what shakes out. But my years of experience say that having three high variance (certainly high length) puzzles, of which solvers must choose which may be easier than others, is a different end selection criterion than who is the fastest solver of everything. Perhaps the Yajilin is actually 5 minutes easier. Perhaps not. I don't know, but the test will probably be determined by squeezing out an unknown large puzzle. It may work for me, or against me, but since I'm often criticized for pointing these things out afterwards if I'm not the winner, I wanted to point out my concern this time well before-hand.

I'm fine with bonus puzzles being used in place of time bonus. But they should almost always be sprint-like puzzles (2-3 minutes max) as you want more, not less, granularity at the end of a test.

can anybody tell how to solve SURAROMU of instruction booklet ?

With most Suraromu puzzles, since you use all gates, one good first step is to draw lines through all the gates with just a single cell width. You'll find doing this and connecting forced paths completes the entire upper-left of the example to give you a line that goes through gates 6 and what must be 7 and 8 (as if they were earlier gates you'd have two gate 4's since the grid has a labeled gate 4). After these initial steps, you have free ends you need to link to future gates and this is where you want to focus your attention:

(1) With the end that just went through 6, how do you get to a gate 5 before passing through gate 4?
(2) With the end that just went through 8, how do you get to gate 9?

To answer (1), you'll see the path through 6 must immediately turn or else it would leave no way to pass through gate 4. So the path goes over two cells (but not three cells) so it can get to another gate and leave a one-cell wide path through gate 4. You'll run into this step a lot. A path "blocks" part of one of the gates (you can X out that cell), but now leaves just one cell to pass through, so it must pass through that cell and the other path has to turn away immediately. With those things marked, the chase of the other end to get gate 9 really only has one option and being "path-efficient" is really key there.

The best thing to do to learn Suraromu puzzles is practice on a dozen or so. The logic is fairly different from other types, but once you learn a few rules the type is almost always very easy to solve. Besides Tom's puzzles, I'd point you to the Circumnavi-Gates on Mathgrant's site as good practice.

Edited by motris 2011-07-06 12:21 AM

thank you
i will try out those.

Re suraromu/slalom, there are some good examples on Melon's Puzzles blog as well. I don;t recall making many suraromu puzzles, so perhaps other sources are a good idea if you want to get some practice in.

Re motris, I'm sort of taking the view from the other side of things. My own testing times for the larger puzzles vary slightly, but then my solving abilities between these 3 types also varies slightly. The fastest possible times are hopefully all about the same, and so then the theory is the participant can choose to sprint on their own terms. This obviously relaxes the whole accuracy of scientifically measuring everyone's performance relative to each other - but on the other hand should hopefully be a little more fun. For example, I've come across comments where yajilin is a bit of a love/hate type for many people. If they happen to love solving yajilin, then great, but if they don't, then they aren't going to be miserable about being forced to solve an arbitrary type as an apparent tie-breaker. The choice adds a little variability, but hopefully not too much.

just as a suggestion.
cant there be another way to answer LITS puzzle its confusing to count number of T's or S's we may miss out one.
answer key similar to NURIKABE or any other.


Edited by rakesh_rai 2011-07-08 7:36 AM

Answer keys can be a fiddly business, and I'm not sure I'm entirely happy with the hashi one either. My tip for LITS is once you've completed the puzzle, to briefly spend some time writing the relevant letter on each of the tetrominoes (this doesn't take very long) and then answers will be relatively easy to read off. Promise!

ok no problem

Puzzle Booklets (one for Main Section, and a separate one for Marathon) uploaded

Main Section Puzzle pdf has 10 pages, including a cover page.
Marathon puzzle pdf has 4 pages, including a cover page. Note that Marathon puzzle pdf file has Landscape orientation.

Both pdf files have same password.

As discussed after Fillomino-Fillia test, a typo will cost 20% of the puzzle value. Of course, one gets 80% only if the author/organizers are certain that the puzzle was solved correctly, but a mistake was made during submission.

Nikoli Selection has started - Good luck to all.

Score page - http://logicmastersindia.com/M201107P1/score.asp

If you've not taken the test yet, you can check who all have taken the test in the score page.
If you've taken the test, you can check details of your submission, and others' scores. If you believe some puzzle is marked incorrectly, please use the score page to 'claim points'.