Friday 30 October 2009

Friday Puzzles #21

So perhaps things have been getting a little too mathsy; and certainly I could do with a sudoku break. So, here are a couple of easy Heyawake puzzles, themed with a small number of numbered rooms. Obviously when you focus on just one of the rules of a puzzle, then you lose some of the richness and variety, and this is the case with these two puzzles. As such they are both pretty easy. Still, I hope they still prove to have at least some fun factor coming from their novelty value. 
    #025 Heyawake – rated easy
    #026 Heyawake – rated easy
I am wondering whether it is possible to do a Heyawake puzzle with no numbered rooms at all – at this stage I’m sort of conjecturing that with enough fiddling about with thin rooms in the corners it ought to be doable…whether that translates into any sort of a fun solve we shall have to see.

All puzzles © Tom Collyer 2009

Friday 23 October 2009

Friday Puzzles #20

Carrying on from last week, here’s another topologically themed sudoku. This week, it’s the turn of the projective plane. You’ll also have noticed that this week, in a noble and glorious gesture to save the planet, I have removed the colouring of the 9-cell marked regions. Indeed, dear reader, I have potentially saved some of your precious, precious, colour printer ink.

Now, this will make things difficult for those who can’t visualise the surface via the given identification space – and so the puzzle isn’t as hard as it might have been. I might revisit this design in coming weeks to really exploit some of the beautiful logic induced by this particular grid structure.
    #024 Real Projective Plane Sudoku – rated medium
All puzzles © Tom Collyer 2009.

Saturday 17 October 2009

Friday Puzzles #19

The eagle eyed amongst you might have noticed I deleted yesterday’s entry and replaced it with this.

Less waffle, more puzzles to actually do! The idea this week is you have a standard sudoku puzzle to do – and rather than using the toroidal identifications, instead you are using those of the Klein bottle. Rather than try and laboriously try and rigorously explain the rules with respect to quotient spaces, topology, covering spaces, orientability and lots of other maths – what I’ve done instead is labelled the grid and coloured everything in so the rules are all completely obvious.

Who[*] says the internet is shortening attention spans and generally making everyone more stupid anyway?
#023 Klein-bottle Sudoku – rated medium
All puzzles © Tom Collyer 2009

[*] Ah wait, that’d be me. Expect less mercy next week.

Friday 9 October 2009

Friday Puzzles #18

Every so often, I suddenly stop, and think about the meanings of the words that people are using. A favourite example of mine is the word “awesome”. This is an adjective which you might apply to something that inspires awe in you. The prospect of seeing a mate down the pub isn’t exactly the sort of thing to stop you in tracks and draw your jaw irresistibly down to the floor as the sheer awe of the situation renders any other possible reaction void – and yet it’s a common enough to hear the word used in such a context. I blame Bill & Ted.

Anyhow, another such word is “inspirational”. This is commonly misused, when the careless student of hyperbole wanted the word “fine”, maybe “splendid” (though certainly not “nice”) or perhaps even they might stretch to “excellent” or “wonderful”. Well perhaps not wonderful if the thing in question wasn’t in fact quite full of wonder, but at any rate any other synonym of the word “good” would have done.

However, this week on, an inspirational 36×20 Masyu puzzle authored by a character with the pseudonym juno was posted. I’m sure you’d like nothing back to ram the previous two paragraphs of pedantry right down my throat, but, alas instead I shall provide you with a 10×10 puzzle that was 100% inspired by juno’s masterpiece. Enjoy!
    #022 Masyu – rated medium

All puzzles © Tom Collyer 2009.

Incidentally, I am not going to post juno’s puzzle. You’ll have to suscribe to to have that particular enjoyment, as well as plenty of others.

Thursday 8 October 2009

Nice Dream


If I start by calling myself a two-time national champion , you have fair warning straight away to go and get things done. Or something else instead of reading this. This is a trademark championship review.

The Saturday started by getting up at a reasonable hour – 7.30am – having my three Weetabix and a nice shower. Coventry is a mere hour away on trains that run frequently to Euston, which is itself within walking distance of the University of London’s Institute of Education. Leaving the house at half 8 was plenty comfortable to get to the competition venue for registration at 10. Whilst at the station, I noticed the train was calling at Milton Keynes which was perfect opportunity to meet up with a friend of mine, Andy, who had qualified for his first competition. I tried my hand at the hard sudoku in the Virgin magazine. I struggled, because it really was hard. Still – it was a slightly more riveting experience than Andy’s itouch.

At the venue, the two of us signed in. To Andy’s bemusement, they were handing out free copies of The Times (waste of £1.50); and to mine there was free refreshments including water (waste of about £1.80). (Although it was decent sized 750ml bottle capable of refills). We sat up against the wall, soaking up the incredible nervous atmosphere. Thankfully this was soon broken as George Danker – a by now championship veteran – appeared together with his loud purple shirt and parents, who, beyond providing moral support, also supplied essential transportation.

The Times journalist rather quickly made a beeline towards us. Whether she already knew of mine and George’s pedigree – or whether we simply appeared to be the only people there who didn’t appear to be frightened rabbits in the headlights, I’m not entirely sure. However, she seemed to be a good sport, and explaining quite how these championships work to yet another journalist was quite relaxing before the actual event started. And in fairness to Mary, she seemed like a good sport.

The first round started with me and Andy being a little late into the hall and having to pick out our seats – resulting in me being a little closer to my perceived main rivals George and last year’s champion Nina Pell than I would have ideally preferred. I also spun right round in a vain effort to try and spot Simon Anthony – who previously authored definitive championship blogs – but instead I could only see his crossword-ing chum Mark Goodliffe. Mark was the runner up when I previously won in 2007, and is currently the national crossword champion. This ought to give a good indication as to just how good he is. One day I hope to finish off a Times cryptic. One day.

Err right, I was talking sudoku wasn’t I? The first four puzzles by my standards started in a sluggish gear, plagued by some unnecessary and really quite half-baked bifurcation efforts to try and speed things along. By the time I’d seen Mark finish – in close to 17 minutes – I needed a mental kick up the backside. I saw the easy steps of logic needed to finish up, and was done in 22 minutes. This was 7th place according to Mark, who had been keeping track of finishers. It turned out that he was only 2nd this right. Andy had messed up a puzzle three times, but eventually had all four done and finished in just under 50 minutes.

There was a little break before the second round began. I started this quick. Really quick. Too quick – I had to restart the first puzzle. Fortunately, the rest of the puzzles solved rapidly and smoothly, and I had finished off before 19 minutes were up. Unfortunately, lots of other people had found the round equally as smooth and rapid to solve, and again I was only 7th. However this doesn’t tell the whole story: at this stage I was absolutely petrified that I had made a mistake, and whilst the lady behind me was convinced I’d be fine, I most definitely was not. And even if I was through, it wasn’t exactly in a convincing fashion. A potential final would require a higher gear.

After a small delay after the second round had concluded, the top 8 were announced. I was rather relieved to be standing up in the (unsurprisingly really) 7th spot. Of the eight, there were four I was familiar with: myself, George, Nina and Mark; the other four included the amusingly named Stephen Gerrard, Jason Shannon, Thomas Drake and Abigail Vallis. As things were to transpire, the latter two were both 18 years old. Narrowly missing out on the final in 9th position was a 15 year old girl called XXX – who was named young champion. Interestingly, of the eight finalists only two were women. I have long held the theory that the so-called battle of the sexes is a knowingly playful myth, only perpetuated to appeal to the housewife market that I imagine Sudoku sells best amongst. In terms of UK champions, Nina is doing very well (2005 and 2008) – and Rachel Roth in 2006 performed the minor miracle of beating David McNeill in competition. You might argue that in being the sole representative for the uglier sex that I am the outlier – but I will point you to the demographics of most championships across the globe, and their winners.

There was a break of about an hour before the grand final – allowing the organisers to compile a finishing list for everyone ranked 9th and below. I talked a little more with George and parents – an interesting episode which featured me misdirecting some poor stranger looking for the right lecture hall twice – and also briefly with Mary again where I suggested the preliminary order of the top 8 was unlikely to be the same as the final standings. I had meant to try and catch a word with Nina, but again I couldn’t see her. Instead, me and Andy went upstairs for a breath of fresh air and walked around Russell Square. This walk almost entirely consisted of Andy telling me that the odds of me being the quickest one from eight were rather slim when it appeared the standard appeared to be quite even. I was holding onto the thought that the puzzles in the final would be harder and thus more favourable to me: I have a knack of seeing where a puzzle-cracking bit of logic ought to be when it is crucial to the solving chain; whereas sometimes if there are several solving chains then my radar goes a little awry. I was banking on the others being lightning quick on “easier” fiendish puzzles, and slowing down significantly when the difficulty was notched up slightly – as had happened in 2008.

The grand final was to be held in the same backroom that I had won in 2007, which felt like a good omen. A better omen was handed to me when the top preliminary ranked finish was allocated first choice of seating in the two rows of four formation that the final would take place under, 2nd preliminary placed got 2nd choice etc. People were filling up the edges and the back row first, which I could only read as a sign of tension and nervousness. I had a choice of two seats being 7th pick, and immediately went for the middle seat in the front row. Everything was calm – until we were all off. I went straight at the first puzzle, hit a sticking point, and so decided to go onto the fourth puzzle. I saw something rather devious quite quickly which got it done, confirming to me that the puzzles were certainly on the hard end of fiendish – if not super-fiendish. With that mental crutch safely in place, I cracked the second and third puzzles without a hitch, feeling my heart rate begin to accelerate as that wonderful moment of realisation hit me that: that I was in with a real chance of winning this.

I had no idea how everyone else was getting on of course, but sometimes you simply get into “the zone”, and I can only assume your subconscious picks up each and every little detail from your surroundings because I just knew. Some of the other seven were given a false sign as to how I was getting on, when about 10 minutes in, I moved my arm swiftly forward to grab my drink, took a slurp and put the bottle back down again in one fluid motion. Andy told me later that some of the others had reacted in such a way that indicated they had thought for a split second that I was going to raise my number.

Having completed three puzzles, with the last one already being half filled in, the adrenaline really started to kick in. I was tempted to bifurcate in an effort simply to get the damn puzzle solved and wrap up the championship; I started to do so but realised quickly that I was so out of practice at doing it efficiently that it was simply a non-starter. This was a wise decision, as I was soon to find the bit that cracked the puzzle. Each of the last few digits I pencilled in seemed to coincide with my pulse, and I made a conscious effort to mentally note the numbers as I wrote them in, to prevent another heartbreakingly infamous transposition. When the last one had gone in, I rather triumphantly thrust forth my number into the hair two-handed, done in slightly under 17 minutes. That faded as I waited for everyone else to finish, and the whole “what if I’ve made a mistake”. This was to last about half an hour until the last of the eight finished, followed by a fairly inept and painstaking reverse reading out of the results – whereby one of us who had finished in 17 minutes had unfortunately made a mistake – which I could have sworn was me but eventually transpired not to be me. At which point I finally knew I’d won.

That was not quite it, the ensuing photos, another brief interview with Mary and a presentation ceremony took a little longer. It was good to see my old trophy back again, and even better to be handed a giant novelty cheque for £1,000. Not accepted at several bars in Central London, apparently. Although a signed freebee Sudoku book was received by a couple on the train back home.

As a postscript, I’m going to stick up the final 4 puzzles. They were published in The Times on 28th September 2009 but haven’t appeared on The Times’ website yet. I don’t have explicit permission to post them, but on the other hand the only reason I’m sticking these up is entirely for demonstrative purposes: there is no income from this website.
    Grand Final Puzzle #1
    Grand Final Puzzle #2
    Grand Final Puzzle #3
    Grand Final Puzzle #4

Friday 2 October 2009

Friday Puzzles #16

You may have heard I became a two-time national champion last weekend. Haha – that’s all well and good because though I’m fairly proficient at solving reasonably difficult sudoku, I’m a bit crap at writing them. Nevertheless, there was no way that I wasn’t going to write a sudoku this week, and here it is.

I expect some rapid times – I haven’t gone at it myself but I suspect that quickest possible is closer to 1 minute than it is to 2.

And with regards to the championships? Expect a nice long and boring write-up of that soon! :)
    #021 Sudoku – rated easy
All puzzles © Tom Collyer 2009

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