WPC 2013: Day 1 Morning

This post comes rather late, since the WPC is done and over and I am already back home. But China has wordpress.com blocked, so I had no means to update this blog. I still wrote the posts up, since jotting my thoughts down has been a good way to wind down after the intensity of a series of WPC rounds, and I figured I would just post them all after it was over and I had blog access again. I’ll be uploading the others about once or twice a day; there’s 5 in all.

I wrote these as though it were the actual day and didn’t bother changing the tense or the predictions and anticipations, so my apologies for when you read some things that will seem anachronistic given the post date.

Day 1 morning is over. It went really, really well.
Round 1 was a “Welcome” team round, making use of the rotating tables in China. Eight puzzles are on the main, stationary part of the table, but each only gives 13 of the 20 rows. Then there eight grids of 7 rows on the rotating part, and solvers are left to figure out how to match things up. As a bit of an aid, the puzzles are in two groups of four: four region types, and four black/white types. All of the types were pretty good for me, and some like LITS or Double Back (which is mine) were right up my alley.
As for the actual round: For once, they seemed to time a round named “Welcome” really well. Our team managed to work pretty efficiently and finished in 28 of the 60 minutes (probably the top), which meant lots of other teams also finished as well. I started with the Double Back. This was a good thing to do, because I was managing to claw my way through it despite the huge difficulty. I needed everything I knew about that type. After that, I drifted around so many other puzzles I don’t even remember what they were, but we were always making pretty good progress. The trickiest part of the round to me was that there seemed to be many grids on the top that worked with one of the black/white types (Binaire), and I ended up trying a grid, seeing it worked, and thought I had the pairing when it was actually not the right one. Well done by the constructors there.
Then came the individuals. Round 2 was “Classics”. These were all the types we’ve come to expect, like Nurikabe, slitherlink, Battleships, etc. The oddball was the hardest puzzle, Sudoku +/-4, which is a Sudoku variation none of us have seen before. Who knows how that got into a “classics” round… our team made lots of jokes about that. Another thing to be wary for was how the Hungarian authors had used the classics round in 2011 for all sorts of crazy novelties within standard types. But they didn’t do that this time.
There were still some really outstanding puzzles though, like the Yajilin with all 0s and an amazing parity constraint turning it into Simple Loop. I didn’t find it since it needed too much counting, but I basically had the idea of subareas of the puzzle breaking on a black-white parity coloring and making progress with that.
Speaking of which, I had a great performance, finishing the round with 3 minutes left, and I don’t believe anyone else finished. I was so happy I was able to get the Sudoku even though it was worth so much. The Domino Halves (Half Dominoes) turned out to be the really hard puzzles though. I lucked out by throwing down the solution to the harder one in about 30 seconds (which is probably where I got those 3+ minutes on everyone), but I really struggled with the easy one and, during the round, had been upset with how much time I had wasted on bad guesses. I felt better when I heard about others’ experience on it.
Next was the feared round 3, “Digital”. Not quite as feared as Borderless in 2011 though. A lot of these dealt with digital clock LED representations of numbers. For example, several types were the usual (Skyscraper Sums, Snail), but instead of giving you numbers they only gave some of the LEDs in some spaces. Others were stranger, like Digital Mess where they put all the LED representations of 0-9 (minus one number, to be determined) in a big platter and made you sort out where each number was, like a dissection puzzle.
Despite everyone else being afraid of the round, I was okay (not great) with it. Once I heard about everyone else’s worries though, like how Ulrich jokingly asked at the instruction meeting if he could skip this round instead of one of the Around the World rounds, then I started looking forward to it as a way to gain ground. And indeed, the round went well for me. I managed to finish everything I started, with only my most hated of the types (Snail) left at 5 minutes. I bashed out the easier one in a few of those, spent the rest of the time checking, and ended up with only one 40 point puzzle undone. So 360 out of 400. I haven’t talked to anyone who touched that score yet, but I haven’t talked to everyone either.
All of these predictions are assuming I didn’t make mistakes. I did quite a bit of checking, and I think I’m likely clean on round 2, save for the sudoku where I decided with 3:05 on the clock that checking that grid would be horrendous and if I did have an error it was unlikely I could fix it. 100 points on the line, but I’m hoping for the best. Round 3… well, I just hope they can read my work. The LED symbols really got in the way of writing things. Otherwise, I think enough checking was done here too.
Next up is rounds 4-7, “Around the world in 80 puzzles”, where four countries (including USA) each contributed a round of 20 puzzles for a WPC first. Each competitor sits for three of the rounds, with various rules about which ones we can miss. Since Thomas, Wei-Hwa, and I wrote the USA round, team USA doesn’t do that one, but we have to do the other three by the Dutch, Indians, and Serbians. These rounds seem to be the substitutes for the innovative round that other WPCs have, although each one has classic types too. My track record on innovatives rounds is not great, with last year’s top score being an anomaly, so I’m pretty scared of how it will go. Let’s hope I can keep the morning’s pace up for those rounds as well…

2 Responses to “WPC 2013: Day 1 Morning”

  1. Thomas Snyder Says:

    (my comments will try to similarly match day order, even though I did not get the chance to write them at the appropriate time)

    I loved that the Welcome round was welcoming and hope the remaining team rounds are also finishable. Somehow I have in the back of my mind that the difficulty of 1 << 13 < 14. I'm glad the wrong Yin Yang top broke quickly enough with the wrong assignment that we could get over the Binaire trap without too much trouble. I personally wonder if all the tops could be Binaire tops on those four grids.

    I know I don't do enough logically with Half Dominoes puzzles but my experience with those in Round 2 agrees they could be challenging. I had 10-11 minutes left to just get those points and I managed to make a fool of myself and get 0. I did spend the time to check my sudoku but it seemed with the constraints rather forcing that was a wasted 2 minutes as I was unlikely to have an error.

    The Digital Round was a complete mess. I didn't have that sentiment entering it, but Ulrich's "Can I skip round 3 and do all the Around the World rounds instead" is definitely how I feel now exiting the morning.

    • MellowMelon Says:

      (this comment, in contrast, leaves anachronism land)

      Now that I’ve gone back and tried to do the puzzles logically, it looks like the Half Dominoes are kind of on the border of logical. Due to the way the diagonals work, where some are too easy to fill up and others are tricky to fill, getting both diagonals to be 5 in the top one does constrain the placement of the 1. But I needed a bit of if-then to nail it down, and it wasn’t completely clean even after that. The bottom one I thought was actually a bit cleaner; you can nail the digit set of the top row immediately, for example. Even so, for speed-solving these in rounds I’d still prefer to go the tweak route, since the logic is very slow-going.

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