The Library of Competitions
Tian2 Editions
A four-division promotion ladder — Bronze, Silver, Gold, Platinum — run online across a compressed January–February season, with a proctored invitational championship final. The flagship US route to the international informatics olympiads.
USACO is unusual among competitive-programming olympiads for its visibility: every student begins in Bronze, and the promotion conditions are explicit and threshold-based. A student who scores above the promotion cutoff in any seasonal contest is moved up to the next division for the following contest. Entry is free and open worldwide — no entry exam, no national qualifier, no team formation. Register a free account, sit the contest, move up.
This transparency is part of what makes USACO the most-recommended starting point for high-school competitive programming. The exact number and timing of contests varies year to year — always confirm the current schedule on the official site.
The four divisions| Division | Topics | Typical problem shape | Promotion threshold (recent) |
|---|---|---|---|
| Bronze | Brute force, simulation, basic sorting / searching, ad hoc | Read input; iterate; check a condition. O(N) or O(N log N). | 700 / 1000 |
| Silver | Greedy, two pointers, prefix sums, BFS/DFS, binary search on the answer | Recognise the right paradigm — a wrong choice fails the time limit. | 700 / 1000 |
| Gold | Dynamic programming, graph algorithms, segment trees, computational geometry | The Gold filter. Requires algorithmic insight and clean implementation. Must be certified. | 700–800 (certified) |
| Platinum | Advanced DP, heavy data structures, flow, hard combinatorics | IOI-style. Typically 5-hour US Open window with one harder problem. | Top of ladder |
For Gold and Platinum divisions, USACO requires a certified start. Online contests open a four-day Friday–Monday window, but problems release Saturday at 12:00 ET — and Gold/Platinum contestants must open the contest in the 12:00–12:15 ET window to earn a certified score. Bronze and Silver are not affected; they may use the full window.
Promotion from Gold to Platinum requires a certified score. The US Open invitation pathway expects at least 2 certified scores from the online season; 3 is the working assumption for a competitive invitation case. A 15-minute window is the entire grace period — there is no make-up start.
The 2025–26 season introduced two notable changes: (1) three online contests in January–February rather than the traditional four-contest season, followed by a first-ever proctored invitational US Open on 28 March; (2) a Platinum reclassification — all prior Platinum competitors except 2025 IOI finalists start the season in Gold. Always confirm current dates and structure on the official schedule.
Contest 1 saw 14,273 distinct users from 100+ countries — the largest field. The Platinum field shrank to 191/180/300 across the three contests due to reclassification, while the Gold field swelled to ~1,917 / 1,366 / 1,245. Bronze remained the largest division on every result page.
Per the official contest rules, the following are grounds for a lifetime ban: working in a team; using generative AI (Copilot, ChatGPT, or equivalents); using a VPN to obscure IP for US students; outside consultation during a live contest; sharing code or information while a contest is live; pre-written templates; multiple accounts; malicious submissions. USACO has stated that cheating disclosures may be sent to the student's school. The move to a proctored 2026 final explicitly references AI-integrity load as a driver.
PathwayAbout 24 IOI finalists are invited to camp at Clemson University in late May. Selection is based on web-contest results plus the proctored US Open. A cohort of top female US students is invited as EGOI finalists. Both groups contend at camp for the 4-person IOI / 4-person EGOI teams. Camp expenses are paid by USACO; IOI/EGOI travel is fully funded.
Recent US results: IOI 2025 (Bolivia) — Rain Jiang (gold), Brian Xue (silver), Bing-Dong Liu (silver), Alex Chen (bronze). EGOI 2025 (Germany) — Helen Law (gold), Luna Hudman (gold), Grace Li (gold), Pearl Yu (bronze).
Bronze in the first contest, Silver in the next, Gold before the season is out. The promotion ladder works.— Editor's note
Unofficial; not affiliated with or endorsed by USACO or its organizers. Analyses are original Tian2 work; official problems and solutions remain © their respective owners and are published free at usaco.org.
| Contest | Users | US submitters | Countries | B→S | S→G | G→P |
|---|---|---|---|---|---|---|
| Dec 2020 | 10,752 | — | 80 | — | — | — |
| Dec 2022 | 14,719 | — | 88 | — | — | — |
| Dec 2023 | 16,732 | 5,794 | 132 | — | — | — |
| US Open 2024 | 4,280 | — | — | — | — | — |
| US Open 2025 | 5,782 | 2,349 | 100+ | — | — | — |
| Jan 2025 | 11,565 | — | — | 700 | 700 | 700 |
| Feb 2025 | 9,339 | — | — | 700 | 700 | 700 |
| 2026 Contest 1 | 14,273 | 5,147 | 100+ | 700 | 700 | 800 |
| 2026 Contest 2 | 9,854 | 3,203 | — | 700 | 700 | 650 |
| 2026 Contest 3 | 7,302 | 3,203 | — | 700 | 700 | 750 |
Source: normalized per-contest results pages archived from usaco.org. Thresholds are from the published results; blank cells = data not available on that page. B→S = Bronze→Silver, S→G = Silver→Gold, G→P = Gold→Platinum.
The official resources page points to: Halim & Halim Competitive Programming, Skiena Algorithm Design Manual, CLRS Introduction to Algorithms, Kleinberg–Tardos Algorithm Design, Sedgewick–Wayne Algorithms, Zingaro Algorithmic Thinking.
