Problems are available here: https://apmo-official.org/static/problems/apmo2021_prb.pdf
I will give myself four hours and do my best to simulate contest conditions. This includes writing up solutions on paper as I would in a real contest. The contest is 4 hours long and has 5 problems.
I have not looked at the questions yet: I know vaguely what they are about but nothing else, aside from one person commenting on the difficulty of p4. I have also not looked at results from 2021.
I currently plan on self-grading, but if I have a solution that doesn't resemble anything I can find or looks sketchy I will ask others about it. A "solve" means something that would earn 5-7 points; I am probably a fairly strict grader.
For some background, I am a 2023 blue MOPper in the TST group. I will not bet on this market during/after the exam
1,000🏅 Top traders
| # | Name | Total profit |
|---|---|---|
| 1 | Ṁ125 | |
| 2 | Ṁ26 | |
| 3 | Ṁ6 | |
| 4 | Ṁ4 |
Unfortunately it seems that problem 4 turned out to be worded very poorly, and I interpreted the problem to be a variant where cheese is allowed to be eaten multiple times, but we only count the cheese that are eaten once (and want to show that there's no way to get 888 cheese eaten once, but there is a way to get at least 666).
Despite this misunderstanding, which makes the problem much harder, I still have what I think is a correct or mostly-correct proof of part (a) (and in the actual version of the problem I would've spent at least 30 minutes less on it) and was very close to finding the construction for part (b) when time ran out. Rip...