Add USACO-Judge: 39 problems, 900 submissions

README.md

@@ -1,3 +1,46 @@
 ---
-license: cc-by-4.0
+task_categories:
+- text-generation
+language:
+- en
+tags:
+- code
+- competitive-programming
+- verification
+- usaco
+size_categories:
+- n<1K
+configs:
+- config_name: problems
+  data_files: problems.jsonl
+- config_name: submissions
+  data_files: submissions.jsonl
 ---
+
+# USACO-Judge
+
+A benchmark for judging competitive-programming solutions: given a problem and a candidate
+solution, decide Accept / Reject, and on Reject, produce a concrete input that breaks the code.
+Existing hacking benchmarks are built entirely from known-wrong candidates, so they only test
+the breaking half of verification. USACO-Judge is balanced 1:2 AC:non-AC, so it also tests
+whether a verifier correctly accepts solutions that are actually correct. Built from 39 official
+USACO 2026 problems and 900 real candidate submissions.
+
+## `problems` (39 rows)
+
+One row per problem: `cpid` (USACO's official problem id — `usaco.org/index.php?page=viewproblem2&cpid=<cpid>`),
+`title`, `contest`, `division`, `problem_number`, `source_url`, `statement_md`, `checker_kind`,
+`time_limit_s`, `memory_limit_mb`, `n_tests`, `n_sample_tests`, `point_scores`, `val_cpp`
+(validator), `std_cpp` (reference solution), `chk_cpp` (custom checker, null for problems that
+use a standard comparator), `std_source_submission_id`, `std_origin`.
+
+## `submissions` (900 rows: 270 easy + 630 hard)
+
+One row per submission: `sid`, `cpid` (links to `problems`), `split` (`easy`/`hard`), `code`,
+`verdict` (`AC`/`WA`/`TLE`/`MLE`/`RE`), `score` (0-100). 300 are AC, 600 are not. The `easy`
+split draws from the 18 Bronze/Silver problems, `hard` from the 21 Gold/Platinum/Open problems.
+
+![USACO-Judge composition](figure_composition.png)
+
+Non-AC candidates are stratified across five score bands (1-19, 20-39, 40-59, 60-79, 80-99),
+each a distinct plateau of suboptimal algorithms rather than a single bug pattern.