Para's Puzzle Site

Thursday, 26 September 2013

TVC XVI Practise

Hello from Vancouver. Currently travelling before the WPC in Beijing. Need to be relaxed when I arrive there. Although maybe adding a small jetlag isn't totally the smartest thing. I was better located in Australia for that.

I wasn't sure if I could post any puzzles this week for the upcoming TVC XVI at Logic Master India.. I wrote a few puzzles on the plane, so I figure I'd share those. I hope they are of some use to people. Hopefully I will be able to compete in the last few days of the CTC and the last TVC. We will see. Everyone have fun at least.

There are four Tapas in this post.
The first puzzle is a Symmetric Tapa. This rule is very influential in the solve, so you really don't need many clues if you place your rectangles smartly. This one has four clues, but really shouldn't be that difficult a solve. I made it 11x11 as that way the rectangles would less likely share an edge if I placed all dots on grid points.
The second puzzle is a Toroidal Tapa. I like this variant. It's a bit trickier to design as you need to set a lot more blocks to make sure you can guide the wall where you want it to. I think this is a genre that can always use some practise, especially with looking around the edges of the grid. This puzzle is 12x12 as I liked this pattern of givens.
The third puzzle is a Transparent Tapa. This is the only genre that hasn't previously appeared on a TVC, so I figured I should at least make one of these. Although people can find a few of them on Prasanna Seshadri's blog. Oddly enough this rule change only means there is one clue that is invalid in normal Tapa. This one is also 12x12. I made an opening and then I noticed it would work more effectively in the corner of the grid. But to make a nice pattern of givens it would be better for the grid to be 12x12.
The fourth puzzle is a Alternative Tapa. This is the hardest of the four puzzles. This is not caused by the variant, as it's not overly influential in the solve. But the normal Tapa bit is pretty challenging and should give you all a bit of a challenge. Although maybe with the CTC you've had enough of those already. This one is 11x11 as it worked nicely with the TVC XVI pattern of letters.

Enjoy and have fun this weekend.

Puzzle can be found below.

Daily League Sudoku #30: Toroidal X-Sums Sudoku

This week a combination of two variants I like. X-Sums Sudoku is a genre that works really well with Jigsaw Sudoku, so I figured it would just as well work with Toroidal Sudoku. It's a bit tricky though as it's much easier to overlook that a certain digit already appears in a region. The puzzle is probably on the harder side, but I don't think any of the logic is overly hard. It's just tricky to keep track of everything with the Toroidal regions. I did add a few clues that aren't necessary for uniqueness. But there were clues planned there to keep the symmetry, but the puzzle proved to be unqiue without needing to put any there. They don't really ruin any of the logic, just create a few shortcuts.

Recap of the last Daily League week:
Sunday: Just One Cell Sudoku by Seungjae Kwak
Monday: Diagonally Non-Consecutive Sudoku by Karel Tesar
Tuesday: Arrow Sudoku by Prasanna Seshadri
Wednesday: Skyscraper Sudo-Kurve by Bastien Vial-Jaime
Thursday: Even-Odd Skyscraper Sudoku by Rishi Puri
Friday: Thermo Sudoku by Tom Collyer

Rules for Sudoku

In this Sudoku some of the regions wrap around the edge of the grid. Numbers on the outside indicate the sum of the first X digits in that row or column seen from that side. X is always the first digit in that row or column seen from that side.

Tuesday, 17 September 2013

Czech Team Puzzle Championship

In the weekend of 7-8 September, the Czech Sudoku and Puzzle Teams Championships were held. The championship was held in Brno. The teams competed in a number of team and individual rounds over the weekend. The Sudoku event was won by the team of Michaela Bieliková, Matúš Demiger, Zuzana Hromcová and Jakub Ondroušek. The puzzle event was won by the Hungarian team of Zoltan Horvath, Pal Madarassy, Major Boglár and Zoltan Nemeth. Full results can be found here.
All Sudokus and puzzles of the championship can be found here. I also provided some of the Sudokus and puzzles for that event. This post will contain all my puzzles.
All my puzzles featured in a single round, together with 2 other puzzles. I hadn't written these puzzles to be a complete round and just wrote a number of different puzzles. It was Karel's idea to use them all together. I chose to write a number of common puzzle types, a number of uncommon and a number of variants of common types. So it's a good mix of puzzles to be featured in a single round. They are mostly puzzle types I had written before, so I knew what to do with them. I'm happy how they turned out and think it was a good mix of easy and hard puzzle.

Puzzles can be found below.

Czech Team Sudoku Championship

In the weekend of 7-8 September, the Czech Sudoku and Puzzle Teams Championships were held. The championship was held in Brno. The teams competed in a number of team and individual rounds over the weekend. The Sudoku event was won by the team of Michaela Bieliková, Matúš Demiger, Zuzana Hromcová and Jakub Ondroušek. The puzzle event was won by the Hungarian team of Zoltan Horvath, Pal Madarassy, Major Boglár and Zoltan Nemeth. Full results can be found here.
All Sudokus and puzzles of the championship can be found here. I also provided some of the Sudokus and puzzles for that event. This post will contain all my Sudokus.
This is the first time I actually provided Sudokus to a championship. Before the start of the Daily League I didn't really regularly write Sudokus. I think I'm getting a bit better on judging difficulty. I provided 3 easier and 3 harder puzzles. I also wrote an examples for each puzzle type. Two of the examples were also included in the championship. I think from the point values of the puzzles, my judgements of difficulty were pretty accurate.

Puzzles can be found below.

Daily League Sudoku #29: Different Difference Sudoku

I based this of a puzzle I've seen as an Instructionless Sudoku I've seen before. I don't remember where it was. As I remember it, it was a Sudoku, where in each nth nonet all differences n were marked (e.g. in nonet 1 all differences of 1, in nonet 2 all differences of 2). This puzzle has the same concept, that in each nonet all instances of a particular difference are marked. Except the differences aren't ordered and you have to figure out which nonet corresponds to which difference.
I hope the explanations of the rules are clear. If someone has a better way to formulate them, I'd appreciate it.
I think if you understand how the basics work, it shouldn't be too hard a puzzle. I've written better Sudokus and I think it can be done more elegantly. But overall I like how it turned out. I hope people enjoy it.

Recap of the last Daily League week:
Sunday: Anti-Diagonal Sudoku by Seungjae Kwak
Monday: No Point to Nine Sudoku by Jakub Hrazdira
Tuesday: Slot Machine Sudoku by Prasanna Seshadri
Wednesday: Figures Sudoku by Bastien Vial-Jaime
Thursday: Killer Sudoku by Rishi Puri
Friday: Diagonal Sudoku by Tom Collyer

Daily League PDF's:
Week 32
Week 33
Week 34

Rules for Sudoku

In this Sudoku, adjacent cells in a given 3x3 box containing numbers differing by n are marked. Adjacent cells with no marking must not contain numbers differing by n. The value of n is different for all 3x3 boxes. There is no restriction on adjacent cells contained in different 3x3 boxes.

Friday, 13 September 2013

TVC XV Practise: Part 3ish

So, I tried today to make puzzles for the remaining three genres of TVC XV, but really nothing useful came out of it. A lot of tried openings, but in the end just a big mess of nothing useful came out of it. I could post something of the messy remnants of what were once good ideas, but I'm going I'm just going to repost the three old puzzles I have already linked in the Introduction. So for those who didn't bother clicking the many links in that post, you can at least get 3 nice puzzles to solve.
I hope everything still helped prepare people for the upcoming weekend. Enjoy and have fun.

Puzzles can be found below.

TVC XV Practise: Part 2

I was debating on whether to finish the other 3 types or posting these already, but figured I might as well post them now. I'm having some trouble designing certain variants. Both Double Back and Twopa are tricky to get right. The Twopa came together when I gave up on making the clue layout symmetric. It was just too much trouble. I will try to post the rest later today. I hope these puzzles are useful though.

The first puzzle is an Outside Tapa. I don't think this one is as nice as Serkan's puzzle from TVC VII but I think it's nice none-the-less. The variant isn't as influential in this puzzle, but has some points that should be important for the solve. But a few of the outside clues are purely to settle uniqueness.
The second puzzle is a Total False Tapa. This variant seems to always require a lot of clues. When I was done with the design I actually went out to edit the puzzle a bit, replacing multiple clues with 8's as the actual value of the clue was unnecessary, meaning that an 8 would work just as well. I think it makes the puzzle a bit nicer a solve. I think the end of the solve it trickiest.
The third Puzzle is a Twopa. It's a really tricky type to design, but I don't think the solve is particularly challenging. The main problem here is that you can't just add clues wherever you want as it might not work for both puzzles or it might not solve differently for both puzzles. But at least neither of the puzzles is solvable completely without solving the other grid.

Puzzles can be found below.

TVC XV Practise: Part 1

Here are the first 4 practise puzzles for TVC XV. I will try to get the other 6 ready for tomorrow, but it can be that this week the practise puzzles come in three instalments. As always certain types cause more issues to construct than others. Especially the Twopa is pretty annoying to construct. I also had some trouble getting the No-Islands started, but I think that one turned out nice.

The first puzzle is a Hexa Tapa. I expect the puzzle in the contest to be a larger puzzle. I think in smaller size they really aren't generally very interesting, so I somewhat expect Serkan to go big and do something nice with it. I don't think this puzzle is too hard, but it isn't too bad. The two 1s on the outside were clues I'd have rather left out, but were necessary for uniqueness.
The second puzzle is a Tapa Skyscrapers. And I guess it's appropriate it's second as it's all 2s. I actually made the Kakuro-Style first and figured I could do the same with this genre. I think this one is the nicer of the two puzzles. It was at least fun to construct.
The third puzzle is a Kakuro-Style Tapa. It has the same inside clues as the Tapa Skyscrapers. I spend ages trying to construct this one, but I couldn't get it out the way I wanted it. People who are familiar with my constructing, know that I'm not all too happy with those 2 inside squares. I just liked how the opening worked and after many tries this was the nicest way to finish it.
The fourth puzzle is a No-Islands Tapa. I had some trouble getting this one started. It also took a little while to get all the constraints in correctly, so my first few tries I would realise too late that I had already broken a constraint or two. If you want to know which constraints, look a bit at the Cave/Corral/Bag genre; that should give you some ideas.

Puzzles can be found below.

TVC XV Practise: Introduction

Saturday, 7 September 2013

Daily League Sudoku #28: Knight's Tour Sudoku

This week again an easier puzzle, at least it should be. I think the variant idea is pretty simple and might have been done before. I debated for a while whether or not to have the knights to move from a grey square to 1 through 9 and then back to a grey square, or to do it the way I did now. I thought this was a nicer way, as I thought the last move from 9 to a random number seemed a bit odd. The design was a bit tricky as it was easy to forget to check all numbers and whether it was still possible to connect the paths. The puzzle is fun although it didn't turn out completely the way I wanted. But as it had to also be a unique Sudoku, it worked out good. I only needed to give 12 clues, which I wasn't expecting. The pattern of 12 was the opening lay out, but I figured I would have to add some more to eventually get the Sudoku unique.
I hope you all enjoy it.

Recap of the Daily League:
Sunday: Average Sudoku by Seungjae Kwak
Monday: Poker Sudoku by Sina Hera
Tuesday: Palindrome Sudoku by Prasanna Seshadri
Wednesday: Little Killer Sudoku by Bastien Vial-Jaime
Thursday: Diagonal Sudoku by Rishi Puri
Friday: Outside Sudoku by Tom Collyer

Rules for Sudoku

In this Sudoku two knights are placed on a grey square with a digit 1. The knights then follow a path of knight's moves towards at least one of the other grey squares with a 9. The path travels through all digits 1 through 9 in order, including the digits in the grey squares. Each 9 should be reached by at least one knight.

Saturday, 31 August 2013

Daily League Sudoku #27: Thermo-Sudoku

I promised something easier this week and I think this should be good. This Thermo-Sudoku has a simple opening that should give away a few quick digits. I was trying to make it without any given digits, but the given layout wouldn't allow it. The one central 5 made it unique though and it fits with the decreasing size of squares. It might be possible to line up the thermometers to make it unique without digits or by adding an extra one in the center, but I like how it turned out. I just hope I haven't misjudged the difficulty again, as I have done before. Enjoy.

Recap of the last Daily League week:
Sunday: Alternative Sudoku by Seungjae Kwak
Tuesday: Even Sudoku with Disjoint Groups by Prasanna Seshadri
Wednesday: Arrow Sudoku by Bastien Vial-Jaime
Thursday: 1-Consecutive Sudoku by Hall Hur
Friday: Irregular Sudoku by Tom Collyer

All puzzles can also be solved at SudokuCup.

Rules for Sudoku

In this Sudoku, there are a number of thermometers. Along each thermometer, digits have to be strictly increasing from the bulb upwards.

Friday, 30 August 2013

TVC XIV Practise: Part 2

This post is a bit delayed. That happens when you discover mistakes in your puzzles. I think I fixed them, but sometimes you just get stuck in a spiral of bad deductions that won't get out of your head. I hope most people will still get some use out of them though, with the late arrival.

The first puzzle is a Tapa Loop. I think this is generally a pretty smooth variant and hardly ever causes real issues. This puzzle is not very difficult and if you understand how the variant works, it should go pretty quick.
The second puzzle is a Regional Tapa. The genre is a little bit restrictive in design but I had fun working with it. I did have a problem where I apparently can't count and had to change some of the regions because one region had one cell too many coloured.
The third puzzle is a Cyclic Tapa. Good for people who like classic Tapa as all deductions are like normal. Some clues just have to work for two grids instead of one. I made a stupid error in construction where I placed one pair of copied clues in different squares. But as the rules don't state they have to be in the same square I think this is still a valid puzzle. It would just look nicer. I like how it turned out. I should, it took me ages to get one out that was a bit interesting.
The fourth puzzle is a Pentapa. I always like puzzles with pentominoes, this one is no different. Certain pentominoes are more easily formed by a Tapa wall. These you can usually deduce pretty quickly and then have to try to avoid for the rest of the solve. The Tapa element still comes forward enough though and it's not just playing with pentominoes.
The fifth puzzle is a Elimination Tapa. This was the one that had the biggest error. I changed one of the digits to make a clue work, except that ruined the deductions of a lot of other clues, so had to fix that. It was luckily not the worst fix. I think it's still a nice puzzle. Good practise for bordering clues.

I hope practising all puzzles will help people in the upcoming TVC XIV. Enjoy.

Puzzles can be found below

TVC XIV Practise: Part 1

I was hoping to post these a little bit earlier, but construction of a few puzzles caused more trouble than planned. I tried to make a puzzle for all types not provided in the introduction, except I couldn't get the Cyclic Tapa to go. I tried to make it 10x10, except I might go for a smaller size to at least have something out. So instead I added a Tapa Turns to this part. The remaining five types will hopefully be out tonight or Friday morning Canberra time.

The first puzzle is a Tapa Clones. This variant allows you to only use five different clues, three of which obey this rule under normal Tapa conditions. So the influence doesn't seem to be very great, but I think it worked out okay in this puzzle.
The second puzzle is a Tapa Turns. I think it worked out pretty well. You can make the "turns" clues be very influential as the no 2x2 squares rule restricts how the clues can work.
The third puzzle is a Wordic Tapa. It's a bit of a tricky puzzle to make. The fact that 4 can be a 0 always is annoying and made the construction tricky. There were a number of times where I had to scrap a puzzle because I had missed alternate solutions where a 4 would turn into a 0 instead of 4 or 5. It could be that the actual TVC puzzle uses a different language and thus the clues don't correspond to the same digits.
The fourth puzzle is a Tapa or not Tapa. A lot of the clues end up having to be coloured. Probably possible to make a puzzle where every clue ends up getting coloured. I think it might sometimes be too easy that a clue can just get coloured as colouring wouldn't do anything to make the solution invalid, instead of having to deduce why it can't be valid. I think it worked out okay, even though I had to sacrifice symmetry for uniqueness.
The fifth puzzle is a Tapa in the Cave. The variant doesn't allow for clues over 3 and 3 clues are a bit more restrictive than normal. The variant seems pretty fun, even though I didn't particularly like the idea at the start. But that seems to more often happen with Zoltan's variant ideas. I had tried a similar idea too before, but couldn't get it out in an interesting way so never posted the puzzle. The puzzle has clue that ruins symmetry, but it was necessary for uniqueness. I couldn't add a clue symmetrically as that would be a valid clue if one was placed there.

Puzzles can be found below.

TVC XIV Practise: Introduction

Upcoming weekend will be TVC XIV on Logicmasters India. I'll be trying to write an example of each puzzle type like last year. I missed TVC XIII as I was a bit late realising it would start and had other puzzles to write at that moment. Puzzles will be posted over the next few days.
I'm using this post to direct you to some of the previous examples of some of the variants used.

Tapa Loop:
http://logicmastersindia.com/lmitests/?test=TVC13
http://logicmastersindia.com/lmitests/?test=M201207P
http://puzzleparasite.blogspot.com.au/2012/07/lmi-practise-logiraces.html
http://yureklis.wordpress.com/2012/07/22/puzzle-43-tapa-loop/

Tapa Turns:
http://anuragthefirst.blogspot.com.au/2012/09/tapa-turns.html

Tapa [Regional]:
http://mellowmelon.wordpress.com/2012/02/22/puzzle-389/
http://logicmastersindia.com/lmitests/?test=M201209P

Pentapa:
http://logicmastersindia.com/lmitests/?test=TVC7

Elimination Tapa:
http://chaosatthesky.wordpress.com/2013/05/15/deception-5/
http://logicmastersindia.com/lmitests/?test=M201305P
http://puzzleparasite.blogspot.com.au/2011/09/puzzle-11-tapa-cross-out.html

Saturday, 24 August 2013

Daily League Sudoku #26: Jigsaw Killer Sudoku

This weekend a combination of two standard Sudoku variants. Although I wouldn't say it's a standard puzzle for either variant. When combining different puzzle types or variants, I think it's important to make sure they come into play together and aren't just in the puzzle together. So for this puzzle I chose a cage layout that could never work in a standard Killer Sudoku, as it could never be unique. But the Jigsaw layout allows you to use this cage layout. This puzzle also uses a tricky set of opening moves that you wouldn't normally see in a Killer Sudoku. I think this is again a harder puzzle and the opening will probably stump a few people, but it's clear logic once you find it. I promise next week I'll come with an easier puzzle. Enjoy!

Recap of the last Daily League week:
Sunday: Difference Sudoku by Seungjae Kwak
Monday: Anti-Knight Windoku by Jakub Hrazdira
Tuesday: Quadruple Sudoku by Prasanna Seshadri
Wednesday: Overlapping Diagonal Sudoku by Bastien Vial-Jaime
Thursday: Diagonally Non-Consecutive Sudoku by Rishi Puri
Friday: Classic Sudoku by Tom Collyer

Rules for Sudoku

Instead of given numbers, you now have a few dashed cages. The number in the cage indicates the sum of the digits in the cage, Digits can't be repeated in any dashed cage.

Click to enlarge

Saturday, 17 August 2013

Daily League Sudoku #25: MaxiMini Sum Sudoku

I think this is also a new idea, but I can hardly know all Sudoku ideas. It's not really anything revolutionary, but I like how it worked out. I already did a similar idea before except it used maximum difference. I also added the minimum constraint here as it helped set up openings. The more frequent Daily League puzzles might get a feeling of deja-vu. This puzzle will probably again turn out on the harder side as the steps are pretty restrictive in order for the opening and it's not till the end that there's a bit more freedom on which clues to use. I've noticed that generally seems to be the deciding factor in what makes my puzzle hard or not. I hope people enjoy it though, I think it's a good solve.

Recap of the last Daily League week:
Sunday: Balanced Sudoku by Seungjae Kwak
Monday: Even Queens Sudoku by Sina Hera
Tuesday: Renban Groups Sudoku by Prasanna Seshadri
Wednesday: Killer Sudoku by Bastien Vial-Jaime
Thursday: One Way Multi-Diagonal Sudoku by Rishi Puri
Friday: Extra Regions Sudoku by Tom Collyer

Daily League PDF's:
Week 29
Week 30
Week 31

Rules for Sudoku

In this Sudoku there are clues on the outside of the grid. Numbers above or left of the grid indicate the maximum sum of two adjacent digits in that row or column. Numbers below or right of the grid indicate the minimum sum of two adjacent digits in that row or column. Each given sum appears at least once in that row or column.

Monday, 12 August 2013

World Puzzle Championship 2013: 80 puzzle around the world and blog

Here are some announcements about the 2013 World Puzzle Championship.

This year's WSC/WPC will be held from October 12th-October 19th in Beijing, China. Any additional information can be found on http://wscwpc2013.sudoku.org.cn/.

There will also be a blog with information specifically about the World Puzzle Championship hosted by the Hungarian organisation on the following link: http://wpc-2013.blogspot.hu.

Lastly, there's a new initiative tested in this year's WPC. There will be numerous outside puzzle contributing teams, each preparing a set of puzzles to solve. This round is called "Around The World in 80 Puzzles", a play on the famous Jules Verne novel. There are four contributing teams, from four different countries, each providing a set of 20 puzzles each. One of the four sets is provided by me and three other Dutch puzzle authors: Hans Eendebak, Tim Peeters and Richard Stolk. If you want to read more about it, you can on the following link: http://wpc-2013.blogspot.hu/2013/08/around-world-in-80-puzzles-introduction.html.

Saturday, 10 August 2013

Daily League Sudoku #24: Greater Than Sudoku

This week a common variant again. I tend to enjoy solving these puzzles, even though design-wise there's usually not that much in them. I just like sudokus without given digits.
I've been busy writing puzzles for other purposes and then I tend to steer towards a simpler, more common variant. This type is really easy to put together. Many solutions will be unique in this type. There's a few constraints the solution should have to qualify, but it's generally just a matter of checking if it has them and then checking how it solves logically. Some have a path that's a bit too easy and others are too hard. I think this one has a nice logical path. Enjoy.

Recap of the last Daily League week:
Sunday: PS Sudoku by Seungjae Kwak
Monday: Jigsaw Sudoku by Jakub Hrazdira
Tuesday: Diagonal Compromise Sudoku by Prasanna Seshadri
Wednesday: Diagonal Sudoku by Bastien Vial-Jaime
Thursday: Non-Consecutive Sudoku by Rishi Puri
Friday: Quad Sum Sudoku by Benz Liang

Rules for Sudoku

In this Sudoku the digits have to obey all Greater than/Less than signs between cells.

Saturday, 3 August 2013

Daily League Sudoku #23: Sum or Difference Sudoku

This week a Sudoku variant themed around today's date. I did it once before for Valentine's day. I somewhat stumbled into it, while just messing around with a few ideas for a Sudoku. I put down a 3 and an 8 and figured I could push it through the whole puzzle. It's split down the left bottom and right top diagonal. It's not too hard a puzzle after realising the opening. Enjoy.
The puzzle is a bit late, but I had to remake part of it as part of the logic was incorrect. Hopefully this one is without error.

Recap of the last Daily League week:
Sunday: One of Eight Sudoku by Seungjae Kwak
Monday: Pairs Sudoku by Jakub Hrazdira
Tuesday: Domino Sudoku by Prasanna Seshadri
Wednesday: Frame Sudoku by Bastien Vial-Jaime
Thursday: Odd-Even Antiknight Sudoku by Rishi Puri
Friday: Nonconsecutive Sudoku by Tom Collyer

Daily League PDF's:
Week 28

Rules for Sudoku

In this Sudoku, a number between two cells indicate either the sum of or the difference between these two cells.
[Edit: Puzzle image adjusted as one of the clues was missing]

Saturday, 27 July 2013

Daily League Sudoku #22: Diagonal Sudoku

This week again something standard and easy. I don't often write classic Sudokus or standard variants. I think it is because I can't really put anything that creative in my designs for them. I can make them visually pleasing, but that is generally it. I like to put interesting logic in my puzzles, but I have trouble achieving that with normal Sudoku. That's probably because there's too many of them out there, that I feel I can't really offer anything new to the mix. Even when I try I tend to have to give up on it, because otherwise I can't get it unique. I think this one worked out okay though. I expect very fast times though from the best solvers. I don't think there are really many stumbling blocks.

Recap of the last Daily League week:

Saturday: Classic Sudoku by Tom Collyer
Sunday: Edge Product Sudoku by Seungjae Kwak
Monday: Just One Cell Samurai Sudoku by Tiit Vunk
Tuesday: Repeated Neighbours Sudoku by Prasanna Seshadri
Wednesday: Outside or Skyscraper Sudoku by Bastien Vial-Jaime
Thursday: Twin Detector Sudoku by Sina Hera
Friday: Even Sudoku by Tom Collyer

Daily League PDFs:
Week 25
Week 26
Week 27

Rules for Sudoku

In this Sudoku you also have to put the digits 1~9 once on the marked diagonals.