Week in Beijing Part 2 : WSC Team, WPF GP Finals, WSC Day 2.

In my previous post, I had left it at the 5th round, which was the last individual round of day 1. However, there was still quite a bit left in Day 1, 3 Team rounds.

Round 6 : Ball Sudoku (25 minutes)

This round consisted of 6 9×9 grids and 12 4×4 grids. The 4×4 grids were already completely solved. Each of these 4x4s connected 2 2×2 corners of 9x9s. It was part of solving to determine which pieces connect where. At the end of all the connection, it would be possible to curve the connected structure into a ball. Oh and, of course, the 6 Sudokus had to be solved too. Each Sudoku solved gave 120 points.

This was another really bad round, in my opinion. There were 2 reasons for this. Firstly, there was absolutely no way this round was even remotely finishable in the allotted time. Only one team (Poland) managed to correctly solve up to 4 out of the 6 Sudokus. No other team even had 3. There were many 0 scores, and unfortunately, team India was one of them. My personal experience was that I almost had a Sudoku solved logically, but couldn’t get it done in time. The rest of the team reportedly guessed their way through to a solution in one, but I guess that turned out to be wrong later.

My second problem with this round was, if at all any team HAD finished, there would be 30 bonus points for, of all things, sticking the grids together. Fortunately (?) the fact that this round was too hard made certain that no one had to get to the ball part. Score – 0/750.

Round 7 : Match (30 minutes)

This was a far simpler(nicer) team round, that involved being given 8 variants, and matching them into 4 pairs of double variants to solve. The variants given were Diagonal, Killer, Windoku, Consecutive, Little Killer, Inequality, Odd-Even, Anti Knight. After team discussions it had come upon me to tackle the Little Killer and whatever we figured out as its pairing. It turned out to be Consecutive. The pair solved nicely. The one major negative for this round, however, was that both grids forming the match HAD to be filled. So after solving using markings from one grid in the other, you’re essentially required to copy everything into the pairing to gain points. This seems so pointless that the question on whether this is necessary was asked multiple times during the doubt solving sessions before the WSC.

So after copying my Little Killer solution into the Consecutive Grid, I saw that Anti-Knight/Killer pairing and Odd/Inequality pairing were getting close to a finish by Rohan, Jaipal and Rishi, but the Diagonal/Windoku pairing seemed impossible. So I quickly went to that and made a guess, got it wrong, made another guess, got it wrong again, so then was making my way through the sure path to solution, when time was up. We had all the rest though, and it seems the Diagonal/Windoku pair was too difficult for many teams. Score – 600/800.

Round 8 : Mahjong Sudoku (30 minutes)

The only difficulty with this round seemed to be to memorize all the Mahjong rules and the Mahjong suits, as this involved completing the grid using Mahjong tiles, following certain Mahjong grouping rules, and Classic Sudoku rules. In the end, our lack of familiarity with the suit differences probably cost  big here. We got the grouping part quickly enough, but then got stuck with using the classic rules because visualizing the suit eliminations just wasn’t happening. We guessed a little and were making progress, but had to remove all the tiles when time was nearing the end, because there were negative points. In the end, we’d placed 39 tiles, out of which one was wrong, which meant 10 negative points. 10 points each for the correct tiles. Score – 370/800.

This was the end of Day 1, and I think India was at 9th after these team rounds, which overall went really poorly.

WPF Grand Prix Finals. 

The Grand Prix was a series of 8 online contests held across the past year. The top 10 were to compete in a separate finals, which was held at this point of the week, right after WSC Day 1. I had placed 13th in the online contests, so though close, I didn’t make the finals. I did volunteer however, as a proctor in the finals. Basically, I was to check the solution of a solver, if wrong, give the sheet back, if correct, give the next sheet, as the 10 solvers raced through 8 Sudokus. “My solver” turned out to be the number 1 seed, Japan’s Kota Morinishi. It was a nice little challenge trying to read his handwriting (and I thought mine was messy!). He started off pretty slow, and was falling behind the rest even after starting with a time advantage as the 1 seed. However, he suddenly started blitzing through the 2nd half, and ended up winning. It was quite awesome watching him solve at that speed towards the end. The rest of the podium was completed by Tiit Vunk from Estonia and Jakub Ondroušek from the Czech Republic, at 2nd and 3rd respectively.

WSC Day 2

As we’d left it, Rohan was 12th, Rishi was 21st, and me 27th. I feel the need to mention that 😛 Day 2 went quite well for me.

Round 9 : Close Relatives (88 minutes)

The round was another variant round, but this time, there were pairs, with one being a common variant, and the other being a slight variation to that variant itself. In all, there were 16 Sudokus. I solved 12 of these, with many high pointers. The highest pointer, a 6-cell Outside Sudoku, is one of the 4 I didn’t solve. I stared at it for 5 minutes, and thought my time would be better spent elsewhere. I then went and promptly broke the Irregular Sudoku with the time coming to a close. Not a good end, but my score seemed solid nonetheless. Score – 422/600.

Round 10 : Great Wall (15 minutes)

Though I did this well enough I do have some criticism here. This was a round with 5 connected Classic Sudokus, forming a “wall” together. Each grid completed would fetch 20 points. The problem here was, the main solve path was restricted to be in a right-to-left direction. This, coupled with the low time of 15 minutes, meant that some solvers were “teased” by the left side, only to reach a dead end and need to rethink, whereas some solvers started from the right and had an easy solve. I was somewhere in between this as I started seeing left, but quickly switched to right, for some inexplicable, but lucky, reason. I ended up solving 4 of the 5 grids, and was really close to finishing the last grid too. Score – 80/100.

Round 11 : Lucky Number 8 (35 minutes)

This went well enough. Not really good, but just par, I think. I did 6 out of 8 of the variants which were all themed on the number 8, because of it being the 8th World Sudoku Championships. Unfortunately one of the ones I didn’t do was the highest pointer. Score – 154/230.

Oh and, we have a detailed article about the week in Beijing now, which doesn’t just deal with my personal experiences.