{"id":"check-double-insert-after-lookup","text":"`checkIfExist` inserts each element into `seen` only after checking for its double/half, which prevents self-matching at the same index","truth_value":"IN","source":"entries/2026/06/06/check-if-n-and-its-double-exist-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"check-double-insert-after-lookup","truth_value":"IN","reason":"premise"}]}}