IOI almost over!

We haven't been able to blog much over the past few days because IOI and quarantine (where they take our phones and internet, and the local media makes a story titled something like "How can the contestants cope without their beloved phones and internet" -_-).

However, now the competition is over, and as a team, Australia did really well. We achieved three silvers (with an almost gold :( ) and a bronze on the official team, and 2 bronzes on the unofficial team. I almost made bronze, being a few points off the cutoff. For day 1, I didn't do as well as I wanted to, however, I kinda made up for it in day 2, being able to score 90 for the problem called "robots", except I missed the easy problem, and I ended up =153rd.

The next day was the second excursion to Australia zoo ... that we didn't go to. Instead of having to wake up at 6:30 - 7 to make it on time, we only had to wake up 8 - 8:30 to be able to eat breakfast. For our 'excursion' we went to South Bank for movies - at really cheap prices ($5.50) - and watched "Man of Steel". So apparently, RSS feeds deliver video data straight to the reader. TIL

The IOI is now almost over, with just the closing ceremony to go. It has been a fun experience competing and meeting other teams, and we were lucky to get a guide who has been awesome for the whole camp.

The tl;dr of Day 1

After 5.5(!) hours filled with panic and mayhem with the grading system collapsing after 90 mins of competition, we finally finished day 1 and had no idea what our scores were. The leaders endured 3 mighty hours of discussion in the General Assembly (GA) meeting discussing how to change the contest to be fair to everyone, but the end result is that the results from Day 1 will stand!

Australia 1 faired very, very well yesterday; the best we have seen from day 1 in a few years. Both Michael/GP and Ray did exceptionally well, both within the top 20. James and Ishraq also sit in good positions to take out medals.

Australia 2 also did remarkably well given the circumstances for which we had not trained, with everyone scoring points; a non-trivial task in the pandemonium!

Let's hope we can all keep up the good work for tomorrow (Day 2) and see if Aus1 can bring home some medals!

Go 'Straya!

Day One

We're about 100 minutes in (out of 300) in day one of the 2013 IOI. You can see a live scoreboard here, and follow the live stream here, which has organisers, tech and problem writers discussing the tasks, live results and IOI in general.

OMG Day Zero

Today was an adventure.

We woke to discover that due to Jewish laws, Shalom college does not serve breakfast on Saturdays, so at 8:30 we were driven by taxi to the airport hungry. We planned to eat breakfast at the airport, but upon arrival we discovered that our plane was leaving about half an hour earlier than we were expecting. This meant we had about five minutes to order and eat breakfast. It was during this five minutes that we realised how much of a misnomer 'fast food' is. Thankfully, due to the amazing power of airport inefficiency, our plane had not left by the time we arrived at the gate.

After our arrival in Brisbane, we rode a bus to the University of Queensland. When we got to our destination, we met our guide, Brooke. She seems like a well informed and helpful guide, which can only be a good thing. Brooke took us to our college and showed us our rooms, which are pretty standard college rooms. It was at this point that my phone notified me that Draftable, a Melbourne-based software company who I did an internship with over last summer holidays, wrote a wonderful blog post wishing me luck.

After this, Brooke took us on a tour around the campus, and showed us the competition hall, where we found Evgeny, a past Australian IOI medallist. Brooke then had to go to a mysterious guide meeting, and we made our way back to the college. On our walk a bus drove past, where we caught a glimpse of Tony Sun, a kiwi IOI contestant. This of course, meant that we had to give chase to the bus, so we could greet the kiwi team.

We had dinner. Standard college fair. Then some of us made a trip to the IGA to get some junk food. Then we bonded with other teams. (Specifically the NZ and UK teams). Badly paced story is badly paced.

OMG IOI

This is the last day of the pre-IOI training camp, which means that tomorrow is the first day of IOI. Very much looking forward to meeting old friends and new in Brisbane.

This IOI will also be the last high school informatics competition I will compete in (except for, maybe, the AIO). I've been doing informatics since I learned Visual Basic 6 for the 2008 AIO in year 7, all because I received a little green pamphlet after sitting the AIC. It will be strange to live without being able to look forward to the next step in my path to an IOI. </drama>

The IOI should be fun. I'm pretty pumped.

Training Day 5

And as quick as it all started, pre-IOI training camp is coming to an end. Tomorrow morning we fly to Brisbane.

The teams are currently sitting their last practice exam before the actual IOI, for which the first exam day is Monday. That's under 72 hours away!

Here's a problem from yesterday's exam which no one solved:

The students and leaders are going to a restaurant for dinner. The restaurant needs to set up two circular tables, which must be of equal size. The restaurant is represented as a convex polygon. What is the largest table size possible that the restaurant can fit two of within their walls?

(Given a convex polygon with up to 50,000 vertices, what is the largest radius r such that two r-radius circles can be placed inside the polygon without intersection?)

In today's exam, one of the problems requires students to help plan the NBN roll-out.

NBN Co needs to build a network of fibre-optic cables to connect a set of (up to 200) towns in an outback region of Australia. One of the towns is already connected to the NBN, but all the others aren't yet. For every pair of towns, NBN Co has determined two values (each between 0 and 255): the time and the cost of building a direct line between them. Rather than just minimising time, or just minimising cost, NBN Co wants to minimise their product (ie. the total time multiplied by the total cost). Where should the fibre-optic cables be placed so that every town is connected by cable (either directly or indirectly) to the town with the NBN connection, at minimum time x cost?

This is quite a difficult problem. Experienced readers might notice that this problem is very similar to finding a minimum spanning tree, which is a well-known problem with fast and relatively simple algorithms that solve it. Unfortunately because the number we're minimising is the product of total time and total cost, we can't easily build up our MST one cable at a time, the way we would if we were minimising only time or only cost. The first, and simplest observation students will have to make is that for a solution to potentially be optimal (the best), there can be no other solution with lower total time AND lower total money. How to exploit this is another matter...

Practice exams and falafels

Today we had our third practice exam, it was one of the most annoying exams that I've done, I got 50% on one question (failing only one test case) at around 10am and stayed on that score for that problem for the rest of the exam.

The rest of the exam was fairly typical, an easy problem and an almost impossible one that even now that we know the algorithm would be extremely hard to code.

We had a very different lunch to usual afterwards, rather than the typical "everyone go off and do their own thing", we instead all sat around a table and got Middle Eastern food to share, constantly finishing the falafels and having Jarrah go up and order more, to the point where we got free ones.

We have also had an extremely controversial update in the training site display style which caused a major uproar in the labs.