Status: IN
Solutions systematically delegate computation to Python standard library abstractions — str() for digit extraction, Counter for frequency counting, set for deduplication, bin().count() for popcount — rather than implementing equivalent arithmetic or bitwise logic manually.
both patterns reflect the same principle: prefer a well-tested stdlib abstraction over a hand-rolled equivalent, trading minor performance for readability and correctness confidence
Depends on (SL): string-over-arithmetic-for-digit-ops, counter-universal-frequency-primitive