Footprint of a Letter

This problem was initially used in MAIO 2025, and has significantly modified for distribution.

This problem was originally designed to be solved within 2hrs, and involved an autograder via API submissions to our competition platform and hand grading. Use of all LLM assistance including reasoning models were allowed.

Preview

You are given four vectors and a simple neural network. Each vector corresponds to outputs of the network when specific letters are passed through the network. These letters left nothing behind aside from these “footprints”. Find the four letters.

Download

Right click this link and select “save as”: maio_2025_letter_footprint_public.ipynb

Editorial

Solution and editorial: https://storage.googleapis.com/aiolympiadmy_public/maio2025_letter_footprint/maio_2025_letter_footprint_solution.ipynb

License

Licensed under CC BY-NC-SA 4.0 — You may share and adapt with attribution, for non-commercial use only, under the same license.

Citation

You are welcome to publish your own solutions to this problem! Please use the provided citation below:

@misc{maio2025_letter_footprint,
    title        = {Footprint of a letter},
    author       = {Tan, Nian Wei and Foo, Tun Jing},
    year         = {2025},
    howpublished = {Blog},
    url          = {https://aiolympiad.my/past-problems/maio2025_letter_footprint},
}