{"id":"happy-number-floyds-o1-space","text":"`is_happy` uses Floyd's cycle detection (tortoise and hare) with O(1) space rather than a hash set, making it the same pattern used in `linked-list-cycle`.","truth_value":"IN","source":"entries/2026/06/06/happy-number-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"happy-number-floyds-o1-space","truth_value":"IN","reason":"premise"}]}}