📜 WAYPOINT LESSON
Final 2-A: Fence Blueprint
⭐ beginner⏳ 40 min read📍 Lesson 205 of 281
Final simulation, problem C: convex hull + integer shoelace. Target: solved within 40 minutes.
Final 2-A — Fence Blueprint. Strict monotone-chain hull, then a doubled shoelace over the HULL, not the input. Graded near-miss: shoelace on the input order.
Final 2-A. The wrong version agrees only on convex, pre-ordered polygons; the concave and random-order tests break it.