Below are the rules for NOI.PH 2025. At the bottom of this page, there is a summary of the changes made relative to the rules for last year’s NOI.PH.

I. Eligibility

  1. The contestant must be enrolled in a school at a level of secondary education or lower, for the majority of the period 1 September to 31 December 2024. (IOI S2.5.1)
  2. The contestant must not be enrolled in a degree program at a tertiary education institution with a half-time or greater load, for the majority of the same period. (IOI S2.5.1)
  3. The contestant must be a Filipino citizen or enrolled at a school in the Philippines for the majority of the same period. (IOI S2.5.1)
  4. The contestant must be born on or after July 1, 2005. (IOI S2.5.2)
  5. The contestant must have a coach who is a teacher or administrator of the school they are enrolled in. The coach registers students for the contest and is the primary point of contact. There can be multiple coaches from one school.
  6. Exceptions to any of the eligibility rules may be requested by emailing [email protected].

II. Contest Structure

  1. This is an individual competition.
  2. Rounds. The competition will be split into two rounds:
    1. The Elimination Round
    2. The Final Round
  3. Topics. In general, tasks follow the Official IOI Syllabus. However, a small number of tasks may require topics listed as “Excluded, but open to discussion,” or “Explicitly excluded” in the official IOI syllabus.
  4. Languages.
    1. Elimination Round. At least C++, Java, and Python3 will be allowed in the Elimination Round. Other programming languages may be allowed depending on the availability of resources.
    2. Final Round. Only C++ and Python 3 are allowed for the Final Round. The exact compilation and execution commands to be used for each language are to be published in a competition environment specification and made known sufficiently in advance to all invited participants.
  5. Clarifications. Clarifications pertaining to a task must be publicly filed by the contestant using the clarification system made available as part of the contest system.
  6. Subtasks. Unless otherwise stated, a task is divided into several subtasks.
    1. Each subtask consists of one or more test files.
    2. A subtask follows additional constraints and simplifying assumptions.
    3. Each subtask is worth a certain number of points.
  7. Scoring.
    1. Subtasks. Unless otherwise stated, a contestant obtains all points for a subtask if they have at least one submission that passes all the test cases belonging to that subtask. There are no penalties for incorrect submissions.
    2. Task. Unless otherwise stated, a contestant’s score for a task is the sum of their best scores over all the subtasks of the task.
    3. Contest. The total score of a contestant for a contest is the sum of the scores over all the tasks.
  8. Ranking. For one contest, participants are ranked based on the following in decreasing order of importance.
    1. Score: the total score of a contestant.
    2. Time penalty: the time the contestant reached that score.

III. Elimination Round

  1. Elimination Round. The Elimination Round will:
    1. Be held online.
    2. Consist of one contest lasting nine to ten days, with the expectation that the contestants will solve the tasks during their free time.
  2. References. Contestants are allowed to use reference materials, physical or digital, that were published before the start of the contest.  If contestants’ submissions contain copied code, they must be properly cited.
  3. Generative AI. Using generative AI to interpret, gain ideas, or generate logic, algorithms, or code for any of the Elimination Round tasks is prohibited.
  4. Invitation to the Final Round.
    1. Top 40. Forty (40) contestants in the Elimination Round will be invited as official finalists to the Final Round provided that they:
      1. Satisfy all eligibility criteria.
      2. Have not been disqualified.
      3. Have confirmed willingness and ability to attend the Final Round.
      4. Are among the top ten (10) contestants from their school.
      5. Are among the top forty (40) contestants satisfying all criteria above.
    2. Additional contestants. Depending on the logistical limitations of the venue of the Final Round, some contestants may also be invited as shortlisted finalists or observers. No such invitations will be made if the Final Round is held online. Shortlisted finalists and observers are:
      1. Not shown in the official standings for the Final Round.
      2. Not eligible for medals or honorable mentions in the Final Round.
      3. Not eligible for invitation to the IOI.
    3. Promotion from shortlisted finalist to official finalist. In case some official finalists are unable to attend the Final Round for any reason, some shortlisted finalists may get promoted to official finalists. The exact rules for promotion are detailed at the end of this page.

IV. Final Round

  1. Final Round. The Final Round will:
    1. Be held on-site.
    2. Consist of two contests, each lasting for five hours.
  2. Official contestants. An official contestant in the Final Round must:
    1. Satisfy all the eligibility requirements.
    2. Have been invited to the Final Round.
    3. Have confirmed their attendance by responding to the invitation on or before the specified deadline.
    4. Have included a copy of their student ID in their response to the invitation.
  3. Student ID. Contestants must bring their student ID to the contest venue. Failure to do so may result in disqualification.
  4. References.
    1. Contestants may not access any reference materials or use digital devices without prior approval during the contest proper.
    2. Contestants are not allowed to access websites aside from those explicitly allowed by the organizing committee during the opening ceremony.
  5. Communication. Contestants must not communicate with anyone but the members of the organizing committee during the contest proper.
  6. Ranking. Participants are ranked based on the following in decreasing order of importance:
    1. Total score: the total score of a contestant across all contests in the Final Round.
    2. Total time penalty: the sum of the time penalties of a contestant across all contests in the Final Round.
  7. Medals.
    1. Gold. A gold medal is awarded to the highest-ranked contestant.
    2. Silver. A silver medal is awarded to the second, third, and fourth contestants.
    3. Bronze. A bronze medal is awarded to the fifth to the tenth contestants.
  8. Honorable Mention. An honorable mention is awarded to non-medalist official finalists who rank within the top half on any one of the contest days.
  9. Invitation to the Pre-Selection Training Sessions. All finalists whether official or not will be invited to join the pre-selection training sessions.

V. Pre-Selection Training Sessions

  1. Pre-Selection Training Sessions. The pre-selection training sessions will span several weeks. These sessions may be held online.
  2. Invitation to the APIO and the In-House Training Camp. At most fifteen (15) active trainees, including shortlisted finalists and observers, in the pre-selection training sessions will be invited to join the APIO and the In-House Training Camp. Priority is based on the level of activity. This is a soft limit for the APIO. Depending on the capacity of the venue and at the discretion of the organizers, additional active trainees may be invited to join the APIO. However, this is a hard limit for the In-House Training Camp.

VI. Asia-Pacific Informatics Olympiad (APIO)

  1. APIO. The APIO is hosted by a different country every year, but participants from a country participate in “remote-onsite” local contest venues in their own country. The Philippines will have one such venue, prepared by NOI.PH. APIO invitees are to join the APIO only at this venue.
  2. Official status and medals. Detailed rules will be available on the website of the APIO host for that year. Conventionally, the top six (6) scorers in a country become the official participants of that country. Official status is only determined after the contest ends, and only official participants are eligible for APIO medals. However, official status and medals are not requirements for invitation to the IOI. Only the final score matters for IOI selection.

VII. In-House Training Camp and In-House Round

  1. In-House Training. The In-House training will be held for a few days between the APIO and the IOI. Participants are to stay in-house for the whole duration.
  2. In-House Round. An in-house round will be administered towards the end of the in-house training.

VIII. Invitation to the IOI

The scientific committee will hold a meeting to decide which among the active trainees will be chosen to represent the country at the IOI. Criteria for the decision shall include (but are not limited to):

  1. Performance in the NOI.PH Final Round
  2. Performance in the pre-selection training sessions
  3. Performance in the APIO
  4. Performance in the in-house training
  5. Performance in the in-house round

Only official finalists are eligible for invitation to the IOI. Shortlisted finalists and observers are still not eligible for invitation to the IOI, even if they joined the APIO and the In-House Training.

IX. Disqualification

  1. Undermining the legitimacy of the contest. Contestants may be disqualified from any of the contests and training camps if the organizing committee reasonably believes that they have attempted to undermine the legitimate operation of any of the contests, by engaging in activities including (but not limited to):
    1. Providing false information about themselves during registration or concerning their eligibility.
    2. Breaching or refusing to comply with the rules.
    3. Sharing or using from others, whether intentionally or unintentionally, any information about a task, including its content or solution, before the end of a round.
    4. Displaying behavior considered to be disruptive, unethical, or unsportsmanlike.
  2. Failing to reply. Contestants may be disqualified if they fail to respond to any request for information from the organizing committee related to NOI.PH and/or the IOI within seven days of our request.
  3. Reporting possible cases. Any harassment, cheating, or violation of these terms may be reported by email to [email protected].

X. Detailed Rules on Invitation to the Final Round

The following steps shall be taken by NOI.PH in determining the Official Finalists and Shortlisted Finalists.

  1. Determine the capacity of the venue.
    1. Call the capacity of the venue Cap. The value of Cap is at least 40.
    2. In the event that Cap cannot be determined yet (for instance if the On-Site Final Round venue hasn’t been finalized), determine a tentative lower bound for Cap, which may be updated later.
    3. If the Final Round is held online, set Cap to 40.
  2. Determine and resolve all disqualification cases.
    1. Remove all disqualified and ineligible participants from the Official Leaderboard.
    2. In all succeeding steps, consider only contestants that remain in the Official Leaderboard.
  3. Compute the Shortlist.
    1. The Shortlist consists of the union of the following sets of participants:
      • The top 50 participants, based on the Official Leaderboard.
      • The top 50 school-qualifying participants.
        • A school-qualifying participant is a participant that is within the top 10 among all participants from the same school.
    2. No participant outside the Shortlist may be added to the Shortlist once it has been decided.
    3. No participant outside the Shortlist may be promoted to Official Finalist or Shortlisted Finalist.
  4. Divide the Shortlist into three groups.
    1. Official Finalists: the 40 top-ranked shortlist-school-qualifying participants.
      • A shortlist-school-qualifying participant is a Shortlisted participant within the top 10 among all Shortlisted participants from the same school.
    2. Shortlisted Finalists: the (Cap – number of official finalists) top-ranked participants in the Shortlist who are not Official Finalists.
      • Note: there is no requirement to be shortlist-school-qualifying.
    3. Wait List: the participants in the Shortlist who are part of neither of the two above groups.
  5. Repeatedly perform recomputations and promotions based on responses of Shortlisted participants to invitations.
    1. For every instance of a participant declining to attend the On-Site Final Round, remove the declining participant from the Shortlist, and perform a recomputation.
      • Note: Participants who do not confirm attendance within the deadline are considered to have declined.
      • Note: Any disqualification occurring after the Online Elimination Round Official Leaderboard has been published is considered equivalent to a declination.
      • Note: Declining is final and may not be revoked.
    2. Every time Cap changes, perform a recomputation.
    3. Recomputation consists of updating the three groups—Official Finalists, Shortlisted Finalists, and Wait List—based on the rules above with the updated Shortlist and Cap.
      • Note: Some participants that are previously not shortlist-school-qualifying may become shortlist-school-qualifying.
    4. Perform recomputations whenever necessary, at any time before the On-Site Final Round. In other words, there may still be promotions even after the deadline for confirmation of attendance has passed.
  6. Observers.
    1. Coaches may request NOI.PH to invite Observers. Address these on a case-by-case basis, and inform the Coach of decisions in a timely manner.
    2. Observers do not enter the Shortlist, nor do they influence the computation of the three Shortlist groups.
    3. The Shortlist takes priority over invited Observers.
      • Observers may be uninvited in case the venue cannot accommodate any more participants. For instance, this may happen when at least Cap Shortlisted participants have confirmed attendance.

XI. Changes to the Rules

NOI.PH reserves the right to change these rules at any time. Such changes will be communicated to all registered participants in a timely manner.

Rules Changelog:

  • Dates under the Eligibility section are updated.
  • All contestants must have a coach who is a teacher or administrator of the school they are enrolled in. The coach registers students for the contest and is the primary point of contact.
  • The use of generative AI is explicitly prohibited.
  • During the Elimination Round, copying code from sources published before the start of the contest is no longer explicitly prohibited. Citing the source is one way to absolve oneself of a plagiarism case.
  • The number of official finalists has increased from 30 to 40.
  • The maximum number of official finalists from one school has increased from 6 to 10.

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