{"id":"counter-missing-key-returns-zero","text":"The `countWords` solution relies on `Counter.__missing__` returning 0 for absent keys — `c2[w] == 1` implicitly rejects words not in `words2` without an explicit membership check.","truth_value":"IN","source":"entries/2026/06/06/count-common-words-with-one-occurrence-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":["counter-universal-frequency-primitive"],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"counter-missing-key-returns-zero","truth_value":"IN","reason":"premise"}]}}