{"id":"counter-outlier-pattern","text":"Using `Counter` to find a unique element among a group reduces the problem from O(n^2) pairwise comparison to O(n) frequency lookup — this pattern recurs across solutions like `majority-element` and `single-number` variants","truth_value":"IN","source":"entries/2026/06/06/odd-string-difference-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"counter-outlier-pattern","truth_value":"IN","reason":"premise"}]}}