{"id":"negation-marking-idempotent-guard","text":"The `if nums[idx] > 0` guard in `find_disappeared_numbers` ensures each index is negated at most once, preventing double-negation by duplicates from restoring a positive sign and producing false \"missing\" results.","truth_value":"IN","source":"entries/2026/06/06/find-all-numbers-disappeared-in-an-array-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"negation-marking-idempotent-guard","truth_value":"IN","reason":"premise"}]}}