How should I practice Versioned Text Correction Previews?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Google onsite interview problems in FastPrep.

Is Versioned Text Correction Previews associated with Google?

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Versioned Text Correction Previews

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Problem statement

A text editor receives correction suggestions from a spelling and grammar model while a user types. Process the supplied ordered events and return a preview for every SUGGEST event.

For this exercise, assume the initial document has revision 0. An ["EDIT", newText] event replaces the entire current document and increases its revision by one, even if its text is unchanged. A ["SUGGEST", revision, start, end, replacement] event is the supplied model output for one half-open character range [start,end).

If the suggestion revision equals the current revision, return ["CURRENT", correctedText], replacing that range with replacement. A preview does not modify the current document or its revision. Otherwise return ["STALE", ""] and ignore the range. This also rejects a revision from the future. Preserve suggestion output order; EDIT events produce no output.

Function

previewVersionedTextCorrections(initialText: String, events: String[][]) → String[][]

Examples

Example 1

initialText = "teh cat"events = [["SUGGEST","0","0","3","the"],["EDIT","teh cats"],["SUGGEST","0","0","3","the"],["SUGGEST","1","0","3","the"]]return = [["CURRENT","the cat"],["STALE",""],["CURRENT","the cats"]]

The edit makes the delayed revision-zero prediction stale.

Example 2

initialText = "a b"events = [["SUGGEST","0","1","2",""],["SUGGEST","0","3","3","!"]]return = [["CURRENT","ab"],["CURRENT","a b!"]]

Both previews use the unchanged document, because suggestions do not commit.

Example 3

initialText = ""events = [["EDIT","hi"],["SUGGEST","1","0","2","hello"]]return = [["CURRENT","hello"]]

The first edit creates revision one.

Constraints

0 <= events.length <= 5000; every event has one of the exact row shapes above.
All text contains ASCII characters and each document or replacement has at most 2000 characters.
Revision, start and end are nonnegative decimal strings. Revision is at most 5000, and 0 <= start <= end <= 2000.
For a current suggestion, end <= currentText.length. Stale suggestion ranges need not fit the current text.
The total number of characters in all current previews is at most 100000. Empty ranges insert text; empty replacements delete text.