Overview
The Hong Kong Olympiad in Informatics (HKOI) is the programming competition for Hong Kong secondary school students. Its results feed into the training team that prepares for international contests such as the International Olympiad in Informatics.
Who can enter
Entry is only through registered day secondary schools in Hong Kong; primary, evening, private and tertiary institutions are not eligible. Contestants compete in one of two groups. For HKOI 2026/27:
Senior Group: born on or after 1 July 2007, not yet finished secondary education, with fewer than 7 years remaining in secondary study.
Junior Group: born on or after 1 July 2010, at S1 to S4 level, with more than 2 years remaining and fewer than 7 years remaining overall.
A school may nominate at most 16 students, 8 for each group.
Levels or stages
Heat Event
Two papers taken back to back with no break. Paper 1 lasts 50 minutes and is worth 25 points, with multiple-choice and short questions in Python or C++. Paper 2 lasts 40 minutes and is worth 20 points, and contestants choose either a Python or a C++ version. At least 96 contestants advance to the Final Event.
Final Event
A 3-hour practical test with four programming tasks worth 100 points each, 400 in total. Solutions are submitted through the Online Judge.
Programming languages and environment
C++20 is the main language; Python 3.10 or later is also allowed, but not every task can be solved in Python. Contestants work on a virtual machine running Debian 13 with Visual Studio Code and g++ 12.
Preparation tips
Practise writing complete C++ programs under time pressure. Past papers and the rules are on the HKOI site.
Can a student register without a school?
No. HKOI accepts nominations only through schools.
Which language should I learn?
C++ is the primary language and every task can be solved in it. Python is accepted, but some tasks cannot be solved with it.