📜 WAYPOINT LESSON
Checkpoint — The Range Climb
⭐⭐⭐ advanced⏳ 25 min read📍 Lesson 270 of 281
A two-subtask query problem: brute banks 40, prefix diffs unlock the rest — both verified.
Điểm kiểm tra — Chiến trình leo trên đoạn. Two rungs, one problem: the per-query rescan banks subtask 1; the prefix-of-differences unlocks subtask 2. Both are verified for real. The wrong solution shows what a single boundary slip costs under all-or-nothing scoring.