how to particepate in the compentation..
please let me know...

Everything is explained, with pictures, on this page: http://logicmastersindia.com/forum/forums/thread-view.asp?tid=382

Edited by Ours brun 2013-04-01 11:38 PM

Is there any penalty for wrong submissions ??

As I know from the earlier contests, there are no penalties.
Your goal is to find the best solution and you will get some points. If your solution does not fulfit the rules, you will get 0 points. Or not?

The PB seems to require a password on my CPU, and leaving it blank says its the wrong pass word :C Help

Edited by zachpuzzle 2013-04-04 4:10 PM

The contest is yet to start. The submission page was enabled by mistake. Sorry about that.

For the first puzzle (Heavy Sky), are the clouds not allowed to touch at all? Or are they allowed to touch diagonally, or is there no restriction on whether they can touch at all?

Generally in this type, they are not allowed to touch by a side or corner.

Confirmation from Riad : Para is correct. Clouds are not allowed touch each other, even at a point.

For Lettered Arrows the answer format on the site requests the values of letters C and H, but in the puzzle booklet it states H and Q. Just wanted to check that C and H is correct?

It should be H and Q. Submission page updated. Please re-enter your answer, accordingly.

[Potential] Score page is now available - link : http://logicmastersindia.com/2013/04Contest/score.asp
Please note that the correctness of submission is not checked.

In Sudoku Optimizer, can we have zero solution for the Sudoku? In other words, can K be equal to 0?

No, K > 0.

in n.6 magitori. can cells with letters be blackened?
in n. 8 am i correct assuming that a belt is a snake that forms a closed loop?

Star Belt rules are giving me a spot of trouble:
a) Is the belt an open path or a loop?
b) What does "inside the belt mean?" Is it on the belt, in the enclosed space, or the union of the above?

Hi Stefano,

6. About this author silent.
8. Yes, you are correct.

Inside a closed loop-"snake". Not on the snake.

Edited by Riad Khanmagomedov 2013-04-05 9:18 PM

In Heavy Sky, what does 'both size greater than 1' mean?
Does it mean that length and width both should be > 1, or the area should be > 1?

The length and width both should be > 1.

No stars on the belt.

For Visibility, the puzzle booklet claims it has a point value of 9, but the online submission has it listed as having a point value of 7. Which is correct?

For Digital Ornament example, number on the left says 7, but the sum of the numbers in the first two rows is 5 + 1 +2 = 8. Is it because, 1 doesn't lie on the horizontal line dividing row 1 & 2?

For Visibility, the answer key shows the "1 or 2 digits" warning when you have two digits entered. Entering a single digit causes the warning to disappear. (Still lets you submit, regardless.)

Fixed.

In Borderless minesweeper there are 4 ways by which a 13 * 13 area can be formed .Which orientation needs to be considered? Also in the example puzzle of the same there is one unaccounted mine which is not part of any clue.How did it come into the picture?

Part of the puzzle is to figure out how it has to go.
The total of mines is given. It's the only place the 4th mine can go.

In simple loop what does Lengths of two neighboring segments must differ by exactly 1 imply?What are neighbouring segments .Can someone explain how this happens in the example puzzle of the same?For persons who might be misguided in their solve by my earlier comment of 4 orientations ,I (might be) wrong on that . :-p

Couple of questions on the optimizers.

For Domino Castle, the answer page notes that "some rows may not be used". Does that mean that if we build the castle into, say, a 12x12 grid, the empty rows/columns don't count against us as the minimum row/column value?

For Tetrasudoku, it's not explicitly stated, but I assume I know the answer: Must the sudoku be solvable at all? That is, is it acceptable to create a puzzle which has no solution, making the value of K=0? (I can't imagine that's okay, but figured I'd bring up the possibility anyway.)

My reading of it is, you're drawing a single loop that passes through each dot. If you count the length of the line from dot to dot, then that length must go up or down by one from one segment to another as you travel the loop. In the example, if we start with the segment in the upper left of the grid and go clockwise, we start with a segment that's 2 units long. The next is 3 units long, then 2, 1, 2, 1, 2, 1, 2, 3, 2, 3, 2, 3, 4, 3, and back to the original 2 unit segment.

Domino Castle : As you see from the example, only 4 rows are used. So it is not necessary to use all the rows.

Tetrasudoku : K > 0. Riad answered this earlier in this thread.

Just to confirm,
In Domino Castle we have to use all dominoes
i.e 1-1,1-2...1-7. ......7-7 so in all "49" dominoes right ?

or is it 1-1,1-2...1-7 then 2-2,2-3..2-7, 3-3.. so in that way 28 dominoes ??

Edited by swaroop2011 2013-04-11 3:06 PM

The standard set is made of 28 different dominoes; I am quite sure that's what we are supposed to use here (like in most domino-based logic puzzles).

ohk got it thank you :)

In domino Castle,
1) Is it possible to have a 2*2 domino (that is placing two dominoes adjacently) or 3*3 as there is no such restriction mentioned in rules ?
2) can castle walls touch each other at corners again nothing mentioned regarding this in rules ??

Edited by swaroop2011 2013-04-12 2:56 PM

You have 28 dominoes. Using all dominoes build a castle. Castle is connected freeform figure.

You can only place two dominoes adjacent (e.g. one above the other) if both left ends match, and both right ends match. You have a set of 28 different dominoes to use, once each...

You have to follow the given rules, but if the rules don't restrict something, then you can do it.

About Domino Castle : Please note that no domino can be used twice. (So each domino has to be used exactly once.)

We can see that in some submissions, a single domino (e.g. 3,4) is used twice. This is not allowed. Those submissions are invalid, and will not be considered.

Yet another note about Domino Castle : The task is to minimize the expresses (R-r)^2+(C-c)^2
Not to maximize it. We see a case, where the player has (probably) tried to maximize it.

I assume our optimised score gets adjusted if the solution is correct but our calculation of the score is wrong?

Yes. The entered values of expressions help us in sorting the submissions, thats it. But if it is wrong, it will be adjusted.

April Contest is now over. Submissions are not accepted any more.

Results will be out when Optimizers are checked manually.

Is it okay to post our optimiser results here before the checking?

Thanks Riad for a lovely set of puzzles.
Nearly all were "How can it be possible to logically solve THIS puzzle?" followed some time later by "AH! How clever..."
Very impressed.
Thank-you again.

Yes.

A total of 28 submitted Tetra Sudoku (+ 1 invalid). All submissions can be found in this pdf.
Riad has not double checked them yet, but if you notice any error or omissions, please bring it up.

Huh. Looking at the submissions, I now realize that I completely missed the "or some of them" part of the instructions. Oh well; doubt I could have done much better anyway. :)

Wow, I am wondering if a human should made up such a great sudoku with only 20 givens. Now I am ashamed of myself of being so naive.
Looking forward to rest of the results.
I must not forget to express my admiration to Riad and his great puzzles. Most of them were really hard and adroit. I should finnish all of them much faster, but forget to think about all the rules at all. I ignore number 0 in arrows and clouds and it costs me a lot of effort till I realized it.

Domino Castle Submissions pdf - Only the horizontal dominos marked, remaining are vertical.

Correctness of rules not checked (e.g. the one in page 11 is definitely invalid). If you notice any other grids missing rules, please post here.

22 submissions (out of which at least one is invalid)

I had the same problem.

One of the best contests ever. Congratulations for a fantastic set of puzzles. Spasiba Riad

Optimal Digital Ornament had most number of submissions.
The pdf is little tough to decrypt, but it is easy for those who have submitted the puzzle.
Riad probably has to spend lot of time checking this manually, so if you notice any errors / missing rules, please share.

My entry (110) has a typo. 2 cells transposed in the BL corner.

...If that cannot be allowed, could my previous 105 entry be considered?

I saw these two cells. It did not change your result (110).

Preliminary results have been published, I thank everyone for their participation and positive responses!

Congratulations to James (this is his second win in my contests), Tomoaki and Taro!

Once again thanks to Andrey Bogdanov, who tested all puzzles and translated them into English. And a special thanks to Deb Mohanty! He prepared pdfs with graphic solutions of optimization puzzles. It was a great pleasure holding contests with Deb .

Wow! I'm really pleased! I was hoping to do well, but was convinced I hadn't done _quite_ enough to win. Well done to Tomoaki and Taro also, Tomoaki in particular has beaten me in many optimising competitions over the years, and he wasn't far off again. :) (e.g. http://www.logic-masters.de/DOM/2009.php)
And this is the first time I've finished in the top 3 for any LMI test, so that's another personal milestone.

Big thanks to Riad, you are very clever at making new puzzle variations. Yes they are often hard, but we have a whole week to enjoy them and conquer their logic, which is a pleasant change from the other styles of 'speedy' competition. And the optimisers, well I struggled with those dominoes, it was early in the final morning when I finally found a solution that might be respectable...
And also thank you to Deb for the pdfs, it is great to see how others approached their solutions.

I guess some people might not have come across optimising puzzles before, so I thought I'd give a walkthrough for how I approached the Tetra-Sudoku puzzle. If someone else wants to discuss the other two, feel free.

I tried placing tetraminos in the grid, then filling them with small digits, but that did not go well. So then I chose a different approach. Also I reread the instructions, and noticed that I didn't have to use all 7 shapes!

It was recently proven that a solveable sudoku must have at least 17 clues, but there are thousands of ways to achieve that. So I started with a 17-clue sudoku like this:

..5 ... 46. 

1.. 27. ... 

8.. ... ... 

 

... ... ... 

... ... .12 

..3 .45 ... 

 

... ... ..1 

..4 ... ... 

.56 ..4 ...

The clues are spread out. I'm allowed to swap around rows and columns, as long as each 'group of 3' stays together. So I do this to try to bring the clues closer together, hopefully into groups of size 4.

... ... ... 

.3. .45 ... 

... ... .12 

 

... ... ..1 

.4. ... ... 

56. ..4 ... 

 

.5. ... 46. 

..1 27. ... 

..8 ... ...

Now I have the clues grouped into two full tetraminoes, and two groups of three, a pair, and a single. So 6 tetraminoes would cover all these clues. But I can't find a way to cover them all with only 5 tetraminoes.

Next I throw away that single 3. So I have a sudoku with 16 clues, and it has 1000+ solutions, but I can cover the remaining clues with 5 tetraminoes. And I can choose which 4 extra digits to add (two next to the 45, one beside the 121, and one joining the 4 to the 46)...
Now is when I also relabel the digits so that the most common (the 4s) become 1s, etc, to minimize the sum. So I'd like to add 4 more 'small' digits if I can.

... ... ... 

... .12 ... 

... ... .34 

 

... ... ..3 

.1. ... ... 

25. ..1 ... 

 

.2. ... 15. 

..3 47. ... 

..6 ... ...

If I add an 8 to R2C4 and an 8 to R7C6 then the grid is solveable except for a 2x2 square. This leads to a score of 69+4=73.

Or if I add a 6 to R2C4 and a 7 to R6C7 then again there is 2 solutions: all of the digits 1-7 can be placed, but there are no 8 or 9 clues to resolve where those go.

... ... ... 

... 612 ... 

... ... .34 

 

... ... ..3 

.1. ... ... 

25. ..1 7.. 

 

.2. ... 15. 

..3 47. ... 

..6 ... ...

I could add an 8-clue now, but going from 2 solutions to 1 solution only saves me 3 points, so I'd rather add a an 'unused' 1-clue and a 2-clue and stay with 2 solutions. After a final switch of columns 4 and 5 (so each shape is different), and another relabeling, this gives a score of 66+4=70.

... 2.. ... 

... 163 ... 

... ... .24 

 

... ... .12 

.1. ... ... 

35. ..1 7.. 

 

.3. ... 15. 

..2 74. ... 

..6 ... ...

(I hope those are readable, it's the only way I could think of to format a 9x9 sudoku grid)

Congratulations James for the top position and thanks for sharing your methodical approach for TetraSudoku.

I tried getting an answer with "randomly" starting with Tetrominoes with 1-2-3-4 and other small numbers. But could never got a score less than 100. (It looks like I am not the only one. I can see many Tetrominoes with 1234 in the pdf).