LC 19
Remove Nth Node From End of List
Medium · LC 1–100
Candidate solution routes
Same-Direction / Read-Write Pointers
Invariant: After processing a[0:read], a[0:write] is exactly its correct stable filtered output, with write no farther than read+1.
candidate confidence: 0.529 · metadata_only
Linked-List Pointer Rewiring
Invariant: prev bounds the correctly processed chain and cur is the first unprocessed node; every original node belongs to exactly one side and remains reachable.
candidate confidence: 0.665 · metadata_only
Opposite-Direction Two Pointers
Invariant: Every uneliminated pair uses endpoints inside [l,r]; a moved endpoint is proven unable to pair with any remaining opposite endpoint to satisfy the goal.
candidate confidence: 0.452 · 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.