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Project: search incident text and count event pressure

Last updated: 3 Oct 202623 min read
project
IntermediateBy AITrove Editorial

An incident console receives a fixed dictionary of alert terms, an immutable incident transcript, a static list of depot coordinates, and a stream of event codes. The same word search does not fit all four jobs. A failure-linked trie reports every overlapping term during one message scan; a suffix array finds arbitrary nonempty substrings in the stored transcript; a k-d tree searches planar depot coordinates; and a count-min sketch gives compact, approximate positive counts. State which index is rebuilt when its input changes. Keep output ordering and error direction explicit.

Text and location contract

Index heat, eat, and seal, then scan overheat seal heat. Require both heat/eat overlaps. Build a suffix array over valve alert valve and find valve at offsets 12 and 0 in suffix order, followed by alert at 6. Check the adjacent common-prefix length for the suffix at offset 0. Index D-19 at (4, 9), D-47 at (18, 7), and D-61 at (12, 22); request the nearest to (16, 9) and expect D-47 with squared distance 8. Add an equal-distance pair and specify the depot-ID tie rule before relying on pruning.

Frequency and boundary contract

Use four counter rows and 47 columns. Record bay-hot seven times and gate-open three times. Check that each estimate is at least its exact count, and deliberately find an unrecorded event code with a positive estimate to expose collision behavior. Reject subtraction, deletion, and zero-weight writes. State that this implementation's deterministic hashes do not supply the formal probability bounds of a separately specified universal hash family. Keep a small exact map in the test code as an oracle, not as part of the fixed-memory sketch.

Acceptance trace

Output
Alert matches: heat/eat overlap, seal, heat/eat overlap
Transcript valve offsets in suffix order: 12, 0
Nearest to (16, 9): D-47, squared distance 8
Recorded bay-hot estimate: at least 7

Cost and failure review

For total term length M, longest term H, message length N, and Z hits, the sparse failure-linked trie has a conservative O(MH + R) build bound for R inherited output references and an O(N + Z) scan. Rank-doubling suffix construction costs O(T log² T) for text length T, while its binary lookup costs O(P log T) for pattern length P. Median-sorted k-d construction costs O(D log² D) for D depots, and nearest search can still visit all D points. A sketch with rows r and width w holds O(rw) counters and hashes every update across r rows. Test empty inputs, collisions, ties, and stale immutable indexes.

Common Mistakes

  • Do not discard suffix alert terms inherited from a failure link.
  • Do not display suffix-order offsets as if they were transcript order.
  • Do not equate Euclidean coordinate distance with road travel time.
  • Do not present an approximate sketch estimate as an exact count.
  • Do not reuse an immutable index after changing its source data.

Connected lessons

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