The Asia Pacific Rules for 2024–2025
The following rules do not apply to teams from South Pacific (Australia, New Zealand, etc.), unless explicitly mentioned. World Finals teams will be selected from the South Pacific Independent Regional Contest, independently of the other Asia Pacific regionals.
The contests covered by these rules are the Asia Pacific Championship, regional contests held in Asia Pacific countries, and preliminary contests accompanying these regionals.
Basic rules of Asia Pacific regionals
A1. A team can participate in at most two regionals.
A2. If a regional is accompanied with preliminary contests, teams from the hosting country of the regional must be qualified for the regional through the corresponding preliminary contests.
A3. Regionals are expected to accept teams from other countries in Asia Pacific. Each regional may set an upper-bound of the number of foreign teams. The director of the regional may define appropriate rules for selecting the foreign teams to be accepted.
A4. Regionals may accept teams from South Pacific as well as other super-regions such as Asia East. These teams are never qualified for the World Finals through Asia Pacific regionals.
A5. Teams from a country hosting a regional should not compete in two regionals in other countries.
Selection rules for the World Finals (part 1)
B1. The winner team of each regional is directly qualified for the World Finals. Here, “winner” is defined as the team with the highest rank after excluding teams from South Pacific or other super-regions.
B2. If two or more teams from a single university are winners of different regionals, only one of them is qualified for the World Finals. The university should select one of them. Optionally, the university can let the teams compete in the Championship to select one of them for the World Finals. (These teams are invited to the Championship. See D1.)
B3. If one of the winner teams from a single university is to be selected in the Championship (see B2), the team with the highest rank among them in the Championship is qualified for the World Finals, regardless of the ranking of teams from other universities in the Championship.
Site scores of regionals
C1. For each regional, its “site score”, say S, is defined as follows.
S = 0.56 * number of universities in the regional
+ 0.24 * number of teams in the regional
+ 0.14 * number of universities in the preliminary contests
+ 0.06 * number of teams in the preliminary contests
+ 0.30 * number of foreign teams in the regional
Here, only the teams solving at least one problem are counted. Teams from South Pacific and other super-regions are counted (not excluded).
Selection rules for the Championship
D1. The winner teams of regionals are invited to the Championship. Their performance in the Championship does not affect their qualification for the World Finals. There is an exception if the teams are competing in the Championship due to the rules B2 and B3.
(Note) From the winner universities, only the winner teams can compete in the Championship. Other teams (second or lower in the university in the regional ranking) are not allowed to compete.
(Note) Winner teams are included in the Championship ranking, but are removed in F1(1) below, not affecting the qualification of teams from other universities.
(Note) A winner team can decline to compete in the Championship while keeping the right to go to the World Finals. However, declining teams cannot be the Asia Pacific Champion of the year.
D2. Two top teams of the South Pacific Independent Regional Contest are invited to compete in the Asia Pacific Championship.
(Note) These teams are never qualified for the World Finals through the Asia Pacific Championship. They can get the title of the Asia Pacific Champion.
D3. Apply the following procedures in this order, to the ranking of each regional. (The regional is called X in the following.)
(1) Remove teams from South Pacific and other super-regions from the ranking.
(2) Remove teams not solving any problem from the ranking. Only teams solving at least one problem are retained.
(3) Remove the teams of winner universities from the ranking. Here, a winner university is the university to which a winner team (see B1) belongs. It may be the winner of the regional X, or of another regional.
(4) Remove the fourth or lower ranked teams of each university from the ranking.
(Note) The maximum number of teams from a single university competing in the Championship is 3. See D4(2).
(5) Recompute the team rank of each remaining team afresh. Let R be the recomputed team rank of a team. Assign the following value to each team in the ranking.
(R − 1) / S
S is the site score (defined in C1 above) of the regional X.
D4. Merge the lists of teams from all regionals in Asia Pacific, and apply the following procedures in this order to the resulting list.
(1) Sort the resulting list in ascending order of the value assigned above.
(2) Strike out the second instance of a single team, if any. Then, strike out the fourth or later instances of teams of a single university. This means that at most three teams are qualified from a single university.
(Note) The fourth or lower teams are already removed in D3(4), but this step is necessary.
(3) From each Asia Pacific country, select one team with the smallest value. This team is qualified for the Championship.
(Note) This is a wild-card rule for under-represented countries. At least one team is qualified from every country. Note that only teams solving at least one problem can be qualified (See D3(2)).
(4) Let P be the number of teams for the Championship. Scan the list from the team with the smallest value, and select teams one by one, skipping those teams already selected in the step (3), until the number of selected teams reach P. These teams are qualified for the Championship.
D5. At most one team should be selected as the wild-card team at the discretion of the Championship director. This team is qualified for the Championship.
Selection rules for the Championship (when some teams declined to compete)
E1. The following rules (E2 — E5) define procedures to select alternative teams when some teams invited to or qualified for the Championship declined to compete. The director can decide not to apply these rules (not to select alternative teams), especially after a certain time limit.
(Note) There will be no penalty to the teams declining to compete in the
Championship.
E2. After the first application of D3(4), before the selection process of qualified teams, give “interpolated ranks” to teams removed from the rankings by the rule D3(4) (fourth or lower teams from a university). Assume that two teams A and B are in the ranking after D3(4), and A’s rank is one higher than B’s rank (A’s rank is R, and B’s rank is R + 1). Also assume there were K teams just before D3(4) between A and B. These K teams (removed by the rule D3(4)) are given interpolated ranks R + 1/(K+1), R + 2/(K+1), …, R + K/(K+1), in the order of their ranks.
E3. When a team invited to the Championship by the rules D1 (winner team of a regional) or D2 (two top teams from South Pacific) declined to compete, the number of qualified teams should be increased by one, i.e., a replacement team should be selected by applying D3 through D4.
E4. When a team qualified by the rule D5 (wild-card by the Championship director) declined to compete, the director should select another team.
E5. When a team X qualified for the Championship by the rules D4(3) or D4(4) declined to compete, restore to each ranking a team Y which had been the third team from the university without counting X, if such a team (Y) exists. Reapply steps of D4 after removing X and restoring Y. Interpolated rank is used for Y in place of the recomputed rank (R in D3(5)).
(Note) If a team selected by D4(3) (wild-card for under-represented countries) declined to compete, another team from the same country will be selected by the reapplication of D4(3) in most cases.
Selection rules for the World Finals (part 2)
F1. World Finals teams are first selected according to B1 — B3 above. Then, the teams with the highest Championship ranks are selected, according to the following procedures.
(1) Strike out the winner teams of regionals and teams from South Pacific in the ranking of the Championship.
(2) Strike out the second or lower ranked teams of a university in the ranking of the Championship.
(3) Let N be the number of the World Finals slots allocated to Asia Pacific. Let M be the number of teams qualified for the World Finals in B1 — B3. Then, top N − M teams of the modified ranking are qualified for the World Finals.
Asia Pacific Champion
G1. The team with the highest rank in the Asia Pacific Championship is the ICPC Asia Pacific Champion of the year.
(Note) The Champion will be recognized at the World Finals Opening Ceremony.