- GitBook
- Unofficial USACO Syllabus (actively maintained based on problem trends)
- The Art of Modular Arithmetic (available for free here)
- RAIL @ Berkeley AI Research
In reverse chronological order and stratified by division, here is the list of released problems, not including contributions to training camp selection tests:
- Triples of Cows, Platinum, US Open 2023: tree dynamic programming with disjoint set union data structure and coloring argument, ft. Benjamin Qi
- Quantum Moochanics, Gold, February 2024: sweep line algorithm with algebraic and number theoretic observations, ft. Benjamin Qi
- Tree Merging, Gold, US Open 2023: tree dynamic programming with tree merging
- Barn Tree, Silver, December 2022: constructive tree depth-first search with memoization, serving as a bridge to tree dynamic programming in higher divisions
- Air Cownditioning II, Bronze, January 2023: subset generation via recursion/bitmasking and array min/max updates, ft. Eric Hsu
- Moo Operations, Bronze, January 2023: reverse engineering minimum solution with string processing
- Photoshoot, Bronze, US Open 2022: challenging ad hoc minimization with greedy string processing