{"id":"nice-substring-divide-conquer-split-correctness","text":"Splitting on a character whose case-counterpart is absent is sound: that character cannot appear in any nice substring, so the answer lies entirely in one of the two halves.","truth_value":"IN","source":"entries/2026/06/06/longest-nice-substring-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"nice-substring-divide-conquer-split-correctness","truth_value":"IN","reason":"premise"}]}}