Thread - Snakes - 26th - 28th Dec - Puzzle Ramayan & IPC Qualifier

@ 2015-12-29 10:51 AM (#20413 - in reply to #20411) (#20413) Top

swaroop2011

Posts: 668

Country : India

swaroop2011 posted @ 2015-12-29 10:51 AM

Pratyu2812 - 2015-12-29 8:28 AM

Taking basic snakes puzzle , when there are numbers outside the box, say 5 , what I generally do is find combinations : 2+3/ 3+2, 4+1/1+4 and find similar combinations with other rows/columns and with trial and error fit it in.

Is there any other logical way to work around? Maybe knowing this will help me with other puzzles too.

Yes, there are quite a few ways or few places to look for.
For classic snakes,
1) Look where the head of snake can move
2) Look where the tail of snake can move
3) Look for Big number clues
4) Look for group of clues together in adjacent rows.
Of course most of solvers , visualize an rough sketch of path as well. But for this contest at least, you don't need that, it moves logically all puzzles.

But in generally knowing these techniques is not enough, but applying it. So in particular if you face any issues for any puzzle, post that and puzzlers here will help you through solving it.

@ 2015-12-29 2:31 PM (#20415 - in reply to #20267) (#20415) Top

anithra

Posts: 5

Country : India

anithra posted @ 2015-12-29 2:31 PM

First timer . Will the solutions be posted?.

@ 2015-12-29 2:36 PM (#20416 - in reply to #20415) (#20416) Top

swaroop2011

Posts: 668

Country : India

swaroop2011 posted @ 2015-12-29 2:36 PM

anithra - 2015-12-29 2:31 PM

First timer . Will the solutions be posted?.

yes , after the test is over.

@ 2015-12-29 2:42 PM (#20417 - in reply to #20267) (#20417) Top

Hotel

Posts: 11

Country : Japan

Hotel posted @ 2015-12-29 2:42 PM

How well did the variants represent the theme of the test ?	variations represented the theme well
What was your opinion of the distribution of easy/hard puzzles?	Just right
What did you think about the puzzle quality of the test?	Very nice
Which set of puzzles did you like the most?	Graffiti Snake
Of the puzzles you solved/attempted, how well did the point values reflect the difficulty?	Most puzzles were worth the right amount
What was your opinion of the booklet formatting and printing?	Just right

@ 2015-12-29 2:52 PM (#20418 - in reply to #20416) (#20418) Top

anithra

Posts: 5

Country : India

anithra posted @ 2015-12-29 2:52 PM

Great!. Thank you.

@ 2015-12-29 5:01 PM (#20419 - in reply to #20267) (#20419) Top

Hotel

Posts: 11

Country : Japan

Hotel posted @ 2015-12-29 5:01 PM

In this test, I think toroidal snake is most difficult. In particular I couldn't find even the first step of two puzzles on page 6. Anyone knows how to start?

@ 2015-12-29 6:47 PM (#20420 - in reply to #20419) (#20420) Top

debmohanty

Country : India

debmohanty posted @ 2015-12-29 6:47 PM

Hotel - 2015-12-29 5:01 PM

In this test, I think toroidal snake is most difficult. In particular I couldn't find even the first step of two puzzles on page 6. Anyone knows how to start?

We are planning to document steps for as many puzzles in this contest, but that will take a while.

In the mean time, here are the steps for Toroidal - 3(9X9)

(Logic and images from Prasanna)

Step 1 : The snake can not turn left from R2C2 because of the 7 clue of column 3.
Step 2 : Since column 2 acts like a border, column 1 will have 5 contiguous cells. We can mark 4 of them.
Step 3 : Column 9 has 2 snake cells. They can not be any of rows 1,2,3
Step 4 : Considering the 2 clue of Row4 and 2 clue of column 9, the snake can not go to R4C1 from R5C1. Instead it must turn and go to R5C9, and then further to R5C8.
Step 5 : The snake must go to R9C9 from R9C1, and then further to R9C8. Also, only one of R1C3 and R3C3 can be a snake cell. There will be remaining 5 snake cells in column 3. Since column 2 acts as a border, these 5 cells have to be contiguous
Step 6 : No more snake cells in row 7. Only one way to put the remaining 2 cells in row 6.
Step 7 : Minor book-keeping should lead to the final solution.

@ 2015-12-29 7:56 PM (#20421 - in reply to #20420) (#20421) Top

Hotel

Posts: 11

Country : Japan

Hotel posted @ 2015-12-29 7:56 PM

debmohanty - 2015-12-29 6:47 PM

Hotel - 2015-12-29 5:01 PM

In this test, I think toroidal snake is most difficult. In particular I couldn't find even the first step of two puzzles on page 6. Anyone knows how to start?

We are planning to document steps for as many puzzles in this contest, but that will take a while.

In the mean time, here are the steps for Toroidal - 3(9X9)

Thanks a lot! It's really useful for me to learn some techniques.

@ 2015-12-30 1:50 AM (#20432 - in reply to #20267) (#20432) Top

puzzlemad

Posts: 28

Country : United Kingdom

puzzlemad posted @ 2015-12-30 1:50 AM

Thanks. As always an enjoyable set - and no answer key mistakes from me either

@ 2015-12-30 3:55 AM (#20434 - in reply to #20405) (#20434) Top

kiwijam

Posts: 187

Country : New Zealand

kiwijam posted @ 2015-12-30 3:55 AM

prasanna16391 - 2015-12-29 12:10 PM
Interesting. If my printer had issues I'd just do this on MS Paint. In fact, I was debating with myself about solving this round on paint because I actually thought I'd be faster, but then I thought solving on paper will help me more with offline competitions and went with that. Still, I personally think Snake is a puzzle which can be done with the fill option on paint. The only variant from the contest for which I'd say its better on paper is Summed Snake. Our notations while solving the puzzle probably differ though.

I did the first couple of classics in Paint while I waited for the printer to print (which is why I had a wrong submission, I didn't colour in the first tail cell specifically and thought it was empty when entering the answer key...!)
But I think all of Horse, Toroidal and Summed benefit from extra notation (Toroidal especially, I like to replicate the cells on the far sides of the grid to better visualize what the snake is doing) so decided that paper solving was best.

@ 2015-12-30 4:03 AM (#20435 - in reply to #20434) (#20435) Top

prasanna16391

Posts: 1801

Country : India

prasanna16391 posted @ 2015-12-30 4:03 AM

kiwijam - 2015-12-30 3:55 AM

Ah, I forgot about Toroidal. I'm generally just good with those without replicating the cells, and it was the same here.

@ 2015-12-30 6:06 PM (#20444 - in reply to #20267) (#20444) Top

An LMI player

An LMI player posted @ 2015-12-30 6:06 PM

How well did the variants represent the theme of the test ?	variations represented the theme well
What was your opinion of the distribution of easy/hard puzzles?	Too many hard puzzles
What did you think about the puzzle quality of the test?	Average
Which set of puzzles did you like the most?	Horse Snake
Of the puzzles you solved/attempted, how well did the point values reflect the difficulty?	Most puzzles were worth the right amount
What was your opinion of the booklet formatting and printing?	Just right

@ 2015-12-31 5:46 AM (#20453 - in reply to #20267) (#20453) Top

An LMI player

An LMI player posted @ 2015-12-31 5:46 AM

How well did the variants represent the theme of the test ?	variations represented the theme well
What did you think about the puzzle quality of the test?	Fairly Nice
Which set of puzzles did you like the most?	Summed Snake
Of the puzzles you solved/attempted, how well did the point values reflect the difficulty?	Most puzzles were worth the right amount
What was your opinion of the booklet formatting and printing?	Just right

@ 2015-12-31 7:35 AM (#20454 - in reply to #20453) (#20454) Top

Administrator

Country : India

Administrator posted @ 2015-12-31 7:35 AM

Leaderboard updated - http://logicmastersindia.com/PR/2015-16-ranks.asp

@ 2015-12-31 8:26 AM (#20455 - in reply to #20454) (#20455) Top

Administrator

Country : India

Administrator posted @ 2015-12-31 8:26 AM

Hotel - 2015-12-29 5:01 PM

In this test, I think toroidal snake is most difficult. In particular I couldn't find even the first step of two puzzles on page 6. Anyone knows how to start?

Steps for Toroidal 12X12

(Logic and images from Prasanna)

Step 1 : The 8 and 9 clues for row4&5 takes up 17 cells. Whatever way it goes since it cant form a loop around the grid, 2 cells space will remain empty. So you have 11 columns to fit in 17 snake cells. In every 2 columns, you can have maximum 3 snake cells. So 10 columns can have max 15. One extra column will have both snake cells. So it is a complete zig zag configuration.		Step 2 : Since it forms a zig zag path, there will be only one exit from row4/5. And it has to be towards row 3 because the 1 clue of row 3 can not be satisfied otherwise.
Step 3 : The snake can not go up from R4C3, because of the 3 clue in that column. So you can complete the Zig Zag configuration. In column 1, 7 of the remaining 8 cells are to be snake parts. So exactly one will not be snake part. If both R1C1 and R2C1 are snake parts, the 4 of row2 can not be satisfied. [ There are 2 cases if both the cells are snake cells. These 2 cases are shown in 2 different images ]
Step 4 : So now row 7 to row 12 of column 1 are snake parts.		Step 5 : Some standard book-keeping stuff.
Step 6		Step 7
Step 8		Step 9

@ 2015-12-31 7:35 PM (#20458 - in reply to #20267) (#20458) Top

debmohanty

Country : India

debmohanty posted @ 2015-12-31 7:35 PM

Solutions appended to puzzle booklet.

@ 2015-12-31 11:18 PM (#20460 - in reply to #20267) (#20460) Top

ashaash11ash

Posts: 55

Country : India

ashaash11ash posted @ 2015-12-31 11:18 PM

Congrats to EKBM, Uvo and Deu for top 3 places. congrats to Prasanna, Amit and Swaroop for top 3 India. Thanx to all 173 participants.

Thanks to deb for giving me the opportunity to conduct the contest. the contest was on a tough side. Toroidal seemed to be the toughest in this contest. there were 22 participants who submitted all the 22 puzzles correctly :)
hoped u all enjoyed the contest. Thanks

@ 2016-01-01 6:58 AM (#20463 - in reply to #20267) (#20463) Top

Administrator

Country : India

Administrator posted @ 2016-01-01 6:58 AM

Steps for Snake - 1

1. The snake has not go up from R7C5, otherwise the 6 clue of row 6 can not be satisfied.
2. At R6C5, the snake has to turn right.

@ 2016-01-01 7:03 AM (#20464 - in reply to #20267) (#20464) Top

Administrator

Country : India

Administrator posted @ 2016-01-01 7:03 AM

Steps for Snake - 2

If the snake passes through R3C1, that end will meet R2C3. No further snake parts are possible in the right side region, so the 3s of R2/3/4 can not be satisfied.