LC 67
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Easy · LC 1–100
Candidate solution routes
Primary
FreeExplicit simulation / state machine
Invariant: At loop entry, state completely describes the real process configuration, and one transition is definitionally equivalent to one rule step.
candidate confidence: 0.503 · metadata_only
Alternate 1
FreeBitwise invariants / XOR cancellation
Invariant: The running XOR equals the XOR of values with odd processed frequency; per-bit counts can be reduced independently modulo a repetition count.
candidate confidence: 0.610 · 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.