Being part of last year’s IOI team, I was automatically selected to APIO. Last year, I did so badly I didn’t even make it to the APIO official team. I hope to win a medal this year.

I spent the first 15 minutes reading the problems, working out where I should start.

I had an idea on Game almost immediately. However, the solution worked for the sample testcases but not the main testcases. I spent some time figuring where my idea went wrong, and finally scored 60 / 100 50 minutes in. I had no idea how to further improve it, so I looked at the other problems.

I still have absolutely no idea how to do Mars.

So I switched to Perm. I had my first idea 75 minutes in, combining different increasing sequences, for example, if $k = 23 = (2^4 - 1) + (2^3 - 1) + 1$, then the permutation will be (4 5 6 7) (1 2 3). That achieved 71.2 / 100.

I then switched between game and perm, looking for ways to improve my solution. 2 hours in, my mind is still blank. Hence, I went working on Mars, solving the case where where $n \le 4$, storing all data in the first square. 30 minutes later, I have 14 / 100 for Mars.

I spent the remaining time mostly on game and perm, but have no progress.

Until the last 15 minutes.

I finally found the 91.36 sol for perm, and submitted with 2 minutes left on the clock.

Final score: $60 + 14 + 91.36 = 165.36$, Bronze.