{"id":"special-positions-precompute-row-col-sums","text":"`numSpecial` precomputes per-row and per-column sums in O(m·n), reducing the per-cell special check from O(m+n) to O(1) — this precomputation pattern recurs across matrix problems like `lucky-numbers-in-a-matrix` and `image-smoother`.","truth_value":"IN","source":"entries/2026/06/06/special-positions-in-a-binary-matrix-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"special-positions-precompute-row-col-sums","truth_value":"IN","reason":"premise"}]}}