USACO

The USA Computing Olympiad (USACO) is the official US competition for high school informatics students worldwide — registration is free and all contests are taken online. As a national-level event it feeds talent to the IOI (International Olympiad in Informatics) and the ICPC, and its results are highly regarded by MIT, Harvard, Carnegie Mellon, UC Berkeley and other top schools — and because some problems resemble interview questions at Google, Facebook and other leading tech companies, strong results also help with future internship applications.

USACO uses a points-based promotion system: three monthly contests run from December to February, followed by the US Open in March (with harder problems) and the US national training camp in May (Chinese students may progress as far as the US Open). Each contest can be started at any time within a 4-day window and lasts 3-4 hours (5 hours for the US Open), with 3-4 problems and a maximum of 1,000 points; roughly 600-800 points usually earns promotion, while a perfect or near-perfect score triggers instant on-the-spot promotion — a strong contestant can climb from Bronze to Platinum in a single contest.

There are four divisions: Bronze, Silver, Gold and Platinum, with newcomers starting at Bronze. Bronze requires only basic programming knowledge, enumeration and simulation; Silver needs greedy algorithms, recursive search and basic data structures (roughly the difficulty of China's CSP advanced group); Gold demands dynamic programming, shortest paths and complexity analysis; and Platinum requires a deep understanding of algorithms, with some problems admitting more than one optimal solution.

Contests support five languages — C++, C, Java, Pascal and Python — with all code submitted online and graded automatically (10 test cases per problem). Since 2023, USACO problems have been published in English only, replacing the earlier bilingual format.