LC 49

Group Anagrams

Medium · LC 1–100

arrayhash-tablesortingstring
Free

Candidate solution routes

Primary

Frequency Table / Coordinate Counting

Free

Invariant: After scanning a prefix, count[x] equals x's exact multiplicity there; counts stay nonnegative and their sum equals inserted items minus consumed items.

candidate confidence: 0.358 · metadata_only

Alternate 1

Prefix State plus Hash Frequency

Free

Invariant: Before processing position i, the table contains exactly the historical prefixes allowed as left boundaries; query-before-insert avoids using a future or self state accidentally.

candidate confidence: 0.368 · metadata_only

How to use this page

Read the statement and constraints first, then validate recognition signals, invariant, and complexity. Candidate score is not correctness evidence.