Hi,

We would like to invite you to participate in the live online mirror contest of Coding & Algorithms Tournament (CAT) 2026 Final Round.

Coding & Algorithms Tournament (CAT) is an open Indonesian nationwide programming competition organized by Ecommurz and CSRelatedCompetitions as a celebration of programming skills. We are proud to announce Google Cloud, Virtu Financial, and Indosat Ooredoo Hutchison as our Gold Partners, Hudson River Trading, Dana, and Candor Analytica Research as our Silver Partners, and BINUS University as our Venue Partner.

More than 2,200 Indonesians registered for this competition. After two preliminary rounds and a Semi Final round, 30 great programmers have qualified to the Final Round to compete for the main prizes. The final round will start (tentatively) at 6 June 2026, 1:30pm (UTC+7).

For everyone else other than the 30 finalists, we invite you to participate in the mirror contest. The tasks will be available in Bahasa Indonesia and English. Note that the mirror contest uses ICPC rules, which has the following main differences compared to the official round:

• The mirror contest has full feedback, while the official round only shows pretest results.
• Each problem scores 1 point in the mirror contest, while each problem scores different number of points in the official round.

The mirror contest will start 10 minutes later than the official round. The contest is 4 hours long and consists of several problems. Please note that we might have to postpone the live online mirror contest in case the official round is delayed. This is to the ensure that the tasks are not available to the public until the official round starts.

The tasks are authored and prepared by jonathanirvings, wiwitrifai, rama_pang, Klungs, and ayaze, and tested by sergiovieri, Pyqe, errorgorn, and ToxicPie9.

See you in the mirror contest.

UPD: Analysis of the round is available here (only in Bahasa Indonesia--use your favorite automated translation tool to translate), and the testdata is available here.

PS: You can also come to the Final Round as an audience (and do the mirror contest there). More details and RSVP here (spoiler: free food and SWAGs!)

PPS: Unofficial list of finalists with their Codeforces account. Codeforces accounts are heuristically found and not provided by the finalists. Let me know if there are any inaccuracies. Also let me know all the missing ones.