B0
Setup
I/O speed, long long, brute force first. Testing on small and boundary cases.
USACO Tutoring
Bronze to Gold.
Weekly sessions tuned to recent USACO contests (2024-2026).
Format
Teaching
One concept, one guided problem, one variant you solve.
Timed set
2-3 problems under contest time.
Review
Debugging, complexity, edge cases.
Promotion gates
- Bronze: Solve Bronze #1, #2, #3 under time.
- Silver: Solve Silver #1, #2, #3 under time.
Courses
Bronze to Silver
8-10 weeks · C++ / Java / Python
B1
Simulation
Track state step by step. Practice: Chip Exchange, Cheese Block.
B2
Counting
Frequency arrays and maps. O(N²) when N ≤ 2000.
B3
Prefix sums
Range sums in O(1), split points. Practice: COW Splits, More Cow Photos.
B4
Sorting + greedy
Sort by key, take obvious choice. Practice: Roundabout Rounding.
B5
Strings
Scan once, count runs and transitions. Practice: Hoof Paper Scissors, Mooin' Time III.
B6
Math
Parity, modular basics, translating constraints into checks.
B7
Casework
Exhaustive cases, edge checklist. Practice: Photoshoot.
B8-B9
Mocks
Full contests under time: 2026 C1 Bronze, 2024 Dec Bronze, 2026 C2 Bronze.
Silver to Gold
10-12 weeks · C++ / Java / Python
S0
Foundations
Complexity, sets and maps, coordinate compression idea, clean helpers.
S1
Prefix sums + diff arrays
Multi-category prefix, range updates. Practice: Lineup Queries, Deforestation.
S2
Sliding window / two pointers
Window invariants, monotone pointers. Practice: Sliding Window Summation.
S3
Binary search on answer
Write check(x) cleanly. Avoid off-by-one.
S4
Greedy + sorting
Exchange arguments, priority queues. Practice: Declining Invitations, Compatible Pairs.
S5
BFS / DFS / flood fill
Adjacency lists, components, grid flood fill. Practice: Ski Slope.
S6
Intervals + sweep line
Sort endpoints, coordinate compression. Practice: 2D Conveyor Belt.
S7
Implementation pressure
Indexing, duplicates, overflow. Practice: FJ Loves Rotations, Cow-libi 2.
S8-S10
Mocks
2026 C1 Silver, 2026 C2 Silver, 2024 Dec Silver, 2025 US Open Silver.