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

Back when we didn’t have dedicated artists, I made art for some problems. Here’s the header for Sorting the Planets:

A flat drawing of some planets in a row.


Here are my problems used for public NOI.PH rounds:

Abakoda Round 3

From Abakoda 2021. A round of four math problems.

Functional Alchemy

From NOI.PH 2020 Finals. An ad hoc problem.

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