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20/10 Puzzle Decathlon - LMI October Puzzle Test #299 posts • Page 3 of 4 • 1 2 3 4
@ 2010-10-18 3:25 AM (#2246 - in reply to #2132) (#2246) Top

detuned



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detuned posted @ 2010-10-18 3:25 AM

I should also mention good job on the puzzles. Nice design on the easy masyu :)
@ 2010-10-18 3:56 AM (#2247 - in reply to #2245) (#2247) Top

motris



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motris posted @ 2010-10-18 3:56 AM

detuned - 2010-10-18 3:23 AM
Thomas - I entered the first column rather than the second for the hard nurikabe. Also on the hard minesweeper, I made a rather silly transposition of digits typing in too quickly. The digits are adjacent - which I think is strong evidence in favour of a typing (as opposed to puzzling) error.

I only mention this as the difference between having these two puzzles marked as right will do wonders (+25%) for my score :)


Having read the thread on the UK forum saying "hey, we all entered wrong columns", I'm surprised you did too. All four got points back though, so you'll get the Nurikabe points.

No go on minesweeper regrading though. It is easy to imagine an incorrect solution with a mine moved by one spot, so I cannot reward an answer there as wrong answers are a lot like right answers on minesweeper.
@ 2010-10-18 4:11 AM (#2248 - in reply to #2132) (#2248) Top

detuned



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detuned posted @ 2010-10-18 4:11 AM

Ah yeah - I can see exactly what you mean re that "tweak" (naturally I maintain my innocence nevertheless). The pain is in losing so much bonus - especially when I realise I forgot to put in the hard battleships. I don't think there should be too much surprise in my general error-proneness though!
@ 2010-10-18 5:52 AM (#2249 - in reply to #2132) (#2249) Top

Gotroch



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Gotroch posted @ 2010-10-18 5:52 AM

Very nice puzzles

My answer of Mutant Minesweeper puzzle is missing digit for last row (there was no tetromino part in last row and that's why I probably forgot to submit it)
First nine rows in my solution looks correct, is it possible to get points for that puzzle?

@ 2010-10-18 5:56 AM (#2250 - in reply to #2132) (#2250) Top

motris



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motris posted @ 2010-10-18 5:56 AM

Results for the 20/10 Puzzle Decathlon are now available. Three solvers completed all the puzzles correctly and congratulations go to Hideaki Jo, Ulrich Voigt, and Florian Kirch for earning gold/silver/bronze in this test. I expect to see many of the same top solvers doing well next week at the 19th WPC in Poland.

Thanks to all for participating, and thanks especially to Deb and Logic Masters India for assistance in hosting this puzzle test.
@ 2010-10-18 6:23 AM (#2251 - in reply to #2250) (#2251) Top

debmohanty




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debmohanty posted @ 2010-10-18 6:23 AM

Thomas, thanks for taking time out to write this test. I'm sure it was helpful practice for everyone with WPC around the corner.

Apart from many top players participating, this was the most successful test at LMI in terms of numbers of players. That is hardly surprising though, given who the author was.
189 players (out of 226) got non-zero scores.

Thank you everyone for participating!

@ 2010-10-18 6:26 AM (#2252 - in reply to #2250) (#2252) Top

uvo



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uvo posted @ 2010-10-18 6:26 AM

Now the contest is over I want to mention that the bonus system is seriously flawed: It is easily possible to lose points by solving a puzzle, which is certainly not desirable. For example, it took me about 12 minutes to solve the Number Skeleton mutant: If I hadn't solved it, I would have scored about 19x9=171 instead of the actual 7x10=70 bonus points - plenty to compensate for just one unsolved puzzle (-30 points).

There are two characteristics of your bonus system, which combined lead to this side effect:
1) Both the puzzles and the time bonus have a similar points per minute factor (1200 points / 120 minutes and 10 points per minute, if all puzzles are solved).
2) The decrease in bonus for not having all puzzles solved is very low (factor 9 instead of 10).
Together, this means that one puzzle where you are slower than the average 10 points per minute is worth less, possibly much less than the equivalent bonus score.

Unfortunately, 1) the mentioned Number Skeleton was not my last puzzle and 2) I didn't think about the bonus system in advance. But even if I had, I would have tried to solve all puzzles nevertheless and not cared about my score. (In a WPC, that might be different.)

The puzzles however were excellent (not that I expected anything less). Funnily enough, for the German Championship four years ago I designed a Battleships puzzle very similar to the hard one here, with the same 2-7-2 clues to work with. And I guessed correctly that the mutant Nurikabe would have twelve pentomino islands, but that didn't help much :-)
@ 2010-10-18 6:42 AM (#2253 - in reply to #2252) (#2253) Top

motris



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motris posted @ 2010-10-18 6:42 AM

uvo - 2010-10-18 6:26 AM

Now the contest is over I want to mention that the bonus system is seriously flawed: It is easily possible to lose points by solving a puzzle, which is certainly not desirable. For example, it took me about 12 minutes to solve the Number Skeleton mutant: If I hadn't solved it, I would have scored about 19x9=171 instead of the actual 7x10=70 bonus points - plenty to compensate for just one unsolved puzzle (-30 points).

There are two characteristics of your bonus system, which combined lead to this side effect:
1) Both the puzzles and the time bonus have a similar points per minute factor (1200 points / 120 minutes and 10 points per minute, if all puzzles are solved).
2) The decrease in bonus for not having all puzzles solved is very low (factor 9 instead of 10).
Together, this means that one puzzle where you are slower than the average 10 points per minute is worth less, possibly much less than the equivalent bonus score.

Unfortunately, 1) the mentioned Number Skeleton was not my last puzzle and 2) I didn't think about the bonus system in advance. But even if I had, I would have tried to solve all puzzles nevertheless and not cared about my score. (In a WPC, that might be different.)

The puzzles however were excellent (not that I expected anything less). Funnily enough, for the German Championship four years ago I designed a Battleships puzzle very similar to the hard one here, with the same 2-7-2 clues to work with. And I guessed correctly that the mutant Nurikabe would have twelve pentomino islands, but that didn't help much :-)


Yes, I thought of this scenario too late after we made the change to 9 of 10 earning bonus points. In the first pass the final puzzle should have been worth ~80 points, so with 9 versus 10 points per minute, you would have to take over 9 minutes to solve it to lose points. With the friendlier bonus system to not penalize entry mistakes, the end result is a puzzle you lose points on if you solve it in more than 3.2 or so minutes. This is certainly less time than the last puzzle a solver is likely to face.

The simplest answer - on a test like this which was pretty well-timed given the test-solvers - is to ignore time bonus and use raw clock time to break ties. That, or a much steeper drop off of the partial value was certainly needed. The partial time bonus was included to address the possibility someone might finish very early, but with an error, as has happened on past tests but that was not really a factor here. Certainly worth more improvements before the next time.

Edited by motris 2010-10-18 6:49 AM
@ 2010-10-18 7:08 AM (#2254 - in reply to #2132) (#2254) Top

Aerion




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Aerion posted @ 2010-10-18 7:08 AM

Ha, I see mathgrant made the same answer entry mistake as I did on the Easy ABC Connect -- accidentally started reading the wrong column halfway down. I felt dumb for not just writing the letters directly in the grid to prevent such a thing, but I feel less dumb knowing I'm in good company. ;)

Thanks for a great set of puzzles! Between this and a new issue of P&A (all while keeping an eye on the baseball), it's been quite the weekend.
@ 2010-10-18 8:20 AM (#2255 - in reply to #2132) (#2255) Top

harmeet



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harmeet posted @ 2010-10-18 8:20 AM

Gr8 set of puzzles Thomas... it was really fun to solve them...

Deb... I think my minesweeper set of puzzles are not scored... can you please check them?
@ 2010-10-18 8:21 AM (#2256 - in reply to #2253) (#2256) Top

keshava.hs



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Country : India

keshava.hs posted @ 2010-10-18 8:21 AM

Hi,Greetings!!Th puzzle set was awesome!!It covered all range of puzzlers. Thanks again.Please find the attached answer for Battleship-Hard, I could not find my mistake.3 Cheers,Keshav
@ 2010-10-18 8:24 AM (#2257 - in reply to #2255) (#2257) Top

debmohanty




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debmohanty posted @ 2010-10-18 8:24 AM

harmeet - 2010-10-18 8:20 AM

Deb... I think my minesweeper set of puzzles are not scored... can you please check them?
I think they were incorrect. I've your answer sheets, I'll double check.
@ 2010-10-18 8:38 AM (#2258 - in reply to #2256) (#2258) Top

debmohanty




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debmohanty posted @ 2010-10-18 8:38 AM

keshava.hs - 2010-10-18 8:21 AM

Hi,Greetings!!Th puzzle set was awesome!!It covered all range of puzzlers. Thanks again.Please find the attached answer for Battleship-Hard, I could not find my mistake.3 Cheers,Keshav
Keshav, R5C9 can't be 1x1 submarine. It has to be a part of 3x1 cruiser OR 4x1 battleship. Remember that R5C9 is a square and not a circle.
@ 2010-10-18 8:44 AM (#2259 - in reply to #2258) (#2259) Top

keshava.hs



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Country : India

keshava.hs posted @ 2010-10-18 8:44 AM

Hi Deb,


Thanks a lot for lightning response!

Since i didnot had printer so used paint brush for solving, where i have painted every cell, which has mislead me.

Thanks for resolving my doubt.

Best Regards,
Keshav
@ 2010-10-18 9:16 AM (#2260 - in reply to #2259) (#2260) Top

rakesh_rai




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rakesh_rai posted @ 2010-10-18 9:16 AM

Thanks for the nice set of puzzles.

For me, the best puzzles were (1) ABC Connect Mutant (2) Skyscrapers Hard and (3) Masyu Mutant.

All hard/mutant puzzles were not of same difficulty (but worth 30 each). So, for those solvers who cannot complete the full set in time, there was some luck/skill in choosing which puzzles to solve. For example, a few mutants - Battleship, Minesweeper, Tents and Tom Tom - were very easy. If only I knew this before the test...Mostly I found that the Hard was tougher than the Mutant.

Some comments on specific puzzles-
ABC Connect Mutant: Tough. But I have now managed to solve this somehow. Liked the way the loops have to be stretched sometimes to make the turns count, especially for 8 and 9.
Number Skeleton Mutant: Tough but solvable logically. Have seen such puzzles on USPC mostly.
Tents Hard: Had to resort to Trial and Error. If someone can show a logical point to start the solve, that would be useful.
Skyscrapers Hard: Very Tough.
Nurikabe Hard: Nice (not difficult). Initially, I thought the 44 was a printing error. But realized that 44 will actually start the puzzle and travel all over the world to finish the puzzle. It looked like a snake puzzle in some ways, where the length is given.
@ 2010-10-18 9:25 AM (#2261 - in reply to #2260) (#2261) Top

rakesh_rai




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rakesh_rai posted @ 2010-10-18 9:25 AM

I have a doubt. Didn't we decide earlier that the Last submitted correct answer timestamp would be used as a tiebreaker? But I see same rank given in case of ties.
@ 2010-10-18 10:18 AM (#2263 - in reply to #2260) (#2263) Top

motris



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motris posted @ 2010-10-18 10:18 AM

rakesh_rai - 2010-10-18 9:16 AM

Tents Hard: Had to resort to Trial and Error. If someone can show a logical point to start the solve, that would be useful.


This tents puzzle actually started with no number clues in the first construction, and makes use of "too crowded if a tent goes this way" logic. The final version got some numbers to steer some of the bottom, and also to distract from the "no numbers" approach. Maybe this image will help you get started.

@ 2010-10-18 10:33 AM (#2264 - in reply to #2132) (#2264) Top

debmohanty




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debmohanty posted @ 2010-10-18 10:33 AM

Very interesting use of too-crowded logic. A quick look at the green tree shows the cell the corresponding tent should be in.

The numbers given in the bottom were definitely distracting, because there were of no use to get the start.
@ 2010-10-18 10:34 AM (#2265 - in reply to #2263) (#2265) Top

rakesh_rai




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rakesh_rai posted @ 2010-10-18 10:34 AM

motris - 2010-10-18 10:18 AMThis tents puzzle actually started with no number clues in the first construction, and makes use of "too crowded if a tent goes this way" logic. The final version got some numbers to steer some of the bottom, and also to distract from the "no numbers" approach. Maybe this image will help you get started.

Thanks motris !! The puzzle solves very smoothly once I use this starting point - and it took hardly 2-3 minutes. Earlier, I was focusing more on the "4" column to get started. Perhaps that was an intended distraction.
@ 2010-10-18 11:01 AM (#2266 - in reply to #2260) (#2266) Top

debmohanty




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debmohanty posted @ 2010-10-18 11:01 AM

rakesh_rai - 2010-10-18 9:16 AM
Nurikabe Hard: Nice (not difficult). Initially, I thought the 44 was a printing error. But realized that 44 will actually start the puzzle and travel all over the world to finish the puzzle. It looked like a snake puzzle in some ways, where the length is given.
In Nurikabe, it was interesting to notice (may be many solvers don't notice during the test) that the easy puzzle had only 3s, the hard puzzle had only 4s and the mutant, obviously, had only 5s.
The Art of Puzzles?
@ 2010-10-18 11:11 AM (#2267 - in reply to #2261) (#2267) Top

debmohanty




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debmohanty posted @ 2010-10-18 11:11 AM

rakesh_rai - 2010-10-18 9:25 AM

I have a doubt. Didn't we decide earlier that the Last submitted correct answer timestamp would be used as a tiebreaker? But I see same rank given in case of ties.
Yes, we had decided that.
For this test, we wanted to have a different tie breaker (#of mutants solved, then #of Hard solved, then #of Easy solved). But we had not announced that before the test. So We removed all the tie-breakers and gave same rank for same points. But the table is still sorted by TimeTillLCS in case points are same.

Btw, I noticed that TimeTillLCS is 78 for you, which is way below others' TimeTillLCS in top 100
@ 2010-10-18 12:11 PM (#2269 - in reply to #2267) (#2269) Top

Nikola



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Nikola posted @ 2010-10-18 12:11 PM

Great puzzles, thanks Thomas! That's why people love your puzzles.

Pay attention to my time, I think that everything would be different if the test lasted 100 minutes. Mutant number crossword is "worthily" for the rest of the my time.

Nikola Zivanovic
@ 2010-10-18 6:32 PM (#2274 - in reply to #2132) (#2274) Top

shankarsudhir



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Country : India

shankarsudhir posted @ 2010-10-18 6:32 PM

I noticed that I've submitted the wrong column in the Hard ABC Connect (instead of column A , it's the one next to A to the right). Any chance to verify if that's correct and acceptable ?

Good set of puzzles. (esp the mutant versions)

-Sudhir
@ 2010-10-18 7:25 PM (#2275 - in reply to #2132) (#2275) Top

shankarsudhir



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shankarsudhir posted @ 2010-10-18 7:25 PM

ignore my last post. Even with that, another mistake i made while submitting is with "E" instead of "C". No points for such carelessness :-)

Sudhir
@ 2010-10-18 10:11 PM (#2277 - in reply to #2132) (#2277) Top

vopani



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vopani posted @ 2010-10-18 10:11 PM

Puzzles were exceptionally good, fun to solve, and in a competitive environment.

I liked Nurikabe (Hard), Tents (Hard), ABC Connect (Mutant), Tents (Mutant) and Minesweeper (Mutants) as the best 5.
I kept going wrong in Number Skeleton (Mutant).

I loved the Hard Nurikabe. It had a nice simple logical solving pattern, but the puzzle was just too cute for me to solve without smiling :-)

Thanks Thomas, for the wonderful weekend :-)
20/10 Puzzle Decathlon - LMI October Puzzle Test #299 posts • Page 3 of 4 • 1 2 3 4
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