Problem Solving Mistake Clinic

Module-Specific Mistake Radar

Failure	Discriminating case	Repair evidence
Assume invariant implies reachability	Parity-compatible but unreachable target	Stronger invariant or complete bounded search
Infer first occurrence from binary-search shape	[0,0,0] in the mystery function	Trace and repaired tie policy
Equate no result with empty witness	Zero coin target	Explicit [] versus None contract
Call a timeout impossible	Budget exhausted before frontier is empty	Unknown status and remaining frontier
Claim tests prove an unbounded theorem	Two formulas agree on three samples	Domain-limited claim or proof
Call reduced input globally smallest	Failure on lengths 1 and 3	State 1-minimal deletion guarantee
Force every result into a planned story	Correct mergesort unrolling	Audit definitions before editing valid steps

Record actual mistakes and uncertainty, their evidence, the changed reasoning, and one fresh check. Do not manufacture failed attempts to satisfy a quota.

Practice Mistake Checks

Revisit P03 if you placed the final boundary inside an empty half-open interval; P09 if parity became a reachability certificate; P15 if duplicates were never traced; and P16 if a local reduction became a global-minimum claim. Show the original assumption, a discriminating case and the repaired claim. Use the practice feedback after preserving your attempt.