Concave corners | Australian Maths Trust

Concave corners

This blog post accounts for the highlights of the Australian IOI team’s fifth day of training at the pre-departure camp at UNSW Sydney, as told by Angus Ritossa. Angus is the veteran of this year’s team, and will be competing at his third IOI this year, having won a silver medal last year.

As has become a tradition, the writer of the blog was again decided by a game over dinner. Since everyone had already written one blog, today was a free-for-all and no-one was safe from having to write it.

Today’s game involved placing queens in a chessboard with some cells blocked out. When placing a queen, it cannot be within range of someone else’s queen (same row, column or diagonal, unless there is a blocked square in between). The first person who is unable to place a queen has to write the blog. The game continued for close to an hour after dinner, and finally I was decided as the writer.

The final state of the game.

Similar to the rest of the camp, we began our day with a 5-hour exam. Getting subtasks was a focus for the whole team, with the risk of pushups if we missed points we should have gotten. Fortunately, everyone was able to score a good amount of points on all the problems and we were spared from having to do pushups. After the exam it was time for lunch, and, much to Kevin’s delight, we ate at Stellini’s [Ed. Kevin’s favourite pasta bar] for the second time, followed by an intense frisbee session.

The afternoon saw a problem session as usual, discussing the problems from the morning’s exams. This was interrupted with a late afternoon trip to Boost, before changing locations to the library where we spent the rest of the afternoon.

“Concave Corners”

Dinner this evening was at a local Japanese restaurant. As pictured above, we invented a new pose named “Concave corners” off the back of Josh and Kevin’s explanation of the hardest problem in yesterday’s trial exam.