{"id":"convert-mutate-join-string-idiom","text":"String manipulation problems (`reverse-only-letters`, `reverse-string-ii`) use the convert-mutate-join pattern: `list(s)` for mutability, in-place modification, then `\"\".join()` — the standard Python workaround for string immutability.","truth_value":"IN","source":"entries/2026/06/06/reverse-string-ii-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"convert-mutate-join-string-idiom","truth_value":"IN","reason":"premise"}]}}