I help organize the National Olympiad in Informatics – Philippines, where my main work is to write and test problems, and help train the Philippine team to the IOI. I talk more about this in Helping out in our NOI.

I also help out with art sometimes. Here’s my artwork, the header for Sorting the Planets, that will hopefully encourage you to try the problem:

A flat drawing of some planets in a row.


Four of my problems have been used for public NOI.PH rounds:

Partial Reduplication

From NOI.PH 2020 Eliminations. A simple string processing problem.

Pakain ng Pahiyas 2

From NOI.PH 2020 Eliminations. A math problem that involves some counting.

Sorting the Planets

From NOI.PH 2019 Finals. A challenging ad hoc problem that can be solved mostly through clever observations.

Exchange Gift

From NOI.PH 2019 Eliminations. A data structure problem about careful implementation.


After writing reflections for math contests, I decided to write reflections for programming contests I joined as well. These cover my junior and senior years in high school:

2017 NOI.PH Finals Reflections
  NOI.PH Team Round Reflections
2018 DISCS PRO Reflections
  NOI.PH Finals Reflections
  IOI Reflections