Does anyone have access to this? https://orac2.info/hub/set/test
New resource (probably and hopefully done by AIO this year): OASIS/GOAT - short solutions as reference to past AIOs.
PLS PULL REQUEST: Added some issues and discussions, can discuss problems here, and fix issues (help if u want i guess, add features you want)
3 Mock AIO Exams are here, all made in like 30 minutes, best quality one is the Mock 2026 AIO
Easier way to install orac2.info userscript: link
DISCLAIMER: None of the 'hidden' or old problems I have in this repository are already public material, which can be accessed from brute-forcing page links, or using the Wayback Machin (old versions of the website)
Website is now live on github pages (just a fancier file explorer tho, adding other stuff soon)
ORAC Solutions to AIO problems, AIIO Problems, Alpha Contest Problems, FARIO Problems, Other ORAC Problems. By the way, if a problem file is just a number, it refers to https://orac2.info/problem/id/. Also, I will not include solutions to questions that are not available to the public.
I'm planning to solve a lot of problems (specifically AIO + AIIO) soon. (Aiming for 5 stars and below full solve), and solving a few easy FARIO cuz I haven't solved any right now for some reason.
Somehow this repo has an average of ~150-200 unique cloners every fortnight but like 5 views, so is that just bots or real people? Someone pls tell me.
Test of graph/table of my solves right before AIO
%%{init: {'theme': 'default'}}%%
xychart-beta
title "Problems Solved"
x-axis "Day" ["Aug 18", "Aug 19", "Aug 20", "Aug 21", "Aug 22", "Aug 23", "Aug 24", "Aug 25", "Aug 26", "Aug 27"]
y-axis "Problems"
line "Solves" [5, 3, 1, 0, 0, 0, 0, 0, 0, 0]
| Type of Problem | Amount |
|---|---|
| AIO | 6 |
| AIIO | 4 |
| Other | 0 |
100 Problems: Jan 2026
125 Problems: Mar 2026
150 Problems: Apr 2026
175 Problems: Sep 2026
All AIO p1-5s: Sep 2026
All 3 star problems: Apr 2026, Tennis Robot II got added recently, so Sep 2026
All AIO problems: ?
All Alpha p1-3s: ?
All 4 star problems: ?
500+ in this years AIO!: ?
A tool located in the top folder of this repository which, as injected as a userscript, shows some old, hidden orac2.info problems, organises problems better, and allows you to mark problems with your own tags.
Now, it comes with editorials for problems (most not added, but slowly and surely they will). However, you need to do 'something' in order to enable the showing of these editorials, to make sure that you have actually tried to solve the problem.
★ Rating approximations
0★: Starter Problem (AIO p1), pretty much just a beginner programming exercise1★: Extremely Trivial (AIO p2-3), usually involves a simple data structure or precomputation
2★: Trivial (AIO p3-4), usually involves implementation of a basic technique like prefix sums or binary search. Can also include an observation.
3★: Easy (AIO p4/Easy AIIO p1), involves implementation of usually 2 basic techniques, as well as some sort of observation.
4★: Medium (AIO p4-5/AIIO p1), multi-part problem involving some harder techniques like DFS or DP, definitely an observation, and usually annoying to implment
5★: Difficult (AIO p6/AIIO p1-3/Easy FARIO), either involves an advanced algorithm with some observations, usually learnt in SoE, or basic algorithms with lots of working by hand. Annoying to implement 90% of the time
6★: Hard (AIIO p3-4/FARIO/Seln Easy), involves advanced algorithms, observations, can start to be interactive. Usually extremely annoying to implement
7★: Very Hard (Hard FARIO/Seln Ex), extremely hard problem with maybe 2 in-contest solves
8/9★: Extremely Hard (Hard Seln/IOI), Usually interactive problems, extremely hard with usually 0 in-contest solves (From australia)
I've also added some old problems which most users can't access now, but given the pdfs/old html stuff (i can only use stuff used from other online sources wayback machine otherwise i could get in trouble). Note that the style is very different, so womp womp kinda.
Also, there are some very brief and kinda unreadable editorials in the form of notes that i got from my tampermonkey, called editorial_data.json or smth like that. I recommend importing it immediately before u get solving bcuz otherwise if u re-import, then it might corrupt your other data like custom sets (working on tool to combine without clashes like this). To do it, enable developer mode or advanced mode (forgot), then reload everything a bunch, then click on the 'storage' tab when editing the userscript.
This is a project being worked on right now, to cover some advanced AIO problems, and topics needed to solve them. This also extends into AIIO problems and topics. I hope to also make a userscript to integrate this into orac2.info.
CP notes which were originally for AIO, but made too long and with too many advanced topics. I've found that these notes are good for solving alpha/aiio problems.
Closer to AIO, I might make some notes more focused on aio, and some common tricks, and ideas that have come up in past p4-6s. Also, there is a version with no code highlighting for printing.
A bunch of half-finished mock exams mostly for AIO, will add Alpha-level ones soon. Some are good quality
If anyone from AMT doesn't like this, just email me at acoder31415@gmail.com. (like aiio 2020)