{"id":"running-sum-prefix-suffix-pattern","text":"Prefix-suffix sum problems use a single-pass running accumulator with the identity `rightSum = total - leftSum - current` to avoid building separate prefix and suffix arrays.","truth_value":"IN","source":"entries/2026/06/06/left-and-right-sum-differences-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"running-sum-prefix-suffix-pattern","truth_value":"IN","reason":"premise"}]}}