The Mirror Index

A easy Python interview practice problem on DataDriven. Write and execute real python code with instant grading.

Domain

Python

Difficulty

easy

Seniority

L4

Problem

A search index `d` maps each document id to the single term it matched, and serving lookups needs the inverse: each term pointing back to its documents. Return a new dict whose keys are the unique terms and whose values are the sorted document ids that had that term, keyed as JSON so each term is stringified (the term `1` becomes `"1"`).

Summary

Every value remembers who pointed to it.

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