Status: IN
Set conversion before scanning loops is a standard repo-wide pattern for upgrading membership/dedup operations from O(n) to O(1) per check.
Set algebra (intersection, difference, membership) replaces manual iteration wherever applicable
Depends on (SL): set-conversion-before-loop-for-o1-lookup, k-distant-uses-set-dedup, find-difference-set-minus-idiom, two-out-of-three-set-algebra