{"id":"single-row-keyboard-precomputed-index-map","text":"`calculate_time` builds a `{char: index}` dictionary from the keyboard string in O(26) time, enabling O(1) lookups per character instead of O(26) `str.index()` calls","truth_value":"IN","source":"entries/2026/06/06/single-row-keyboard-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"single-row-keyboard-precomputed-index-map","truth_value":"IN","reason":"premise"}]}}