📜 WAYPOINT LESSON
Checkpoint: the sorted merge
⭐⭐ intermediate⏳ 25 min read📍 Lesson 108 of 256
Two-pointer merge with remainder drains — ArrayList's signature synthesis.
The merge is three machines in a trench coat: a two-pointer comparison,
and two sentinel drains. Get the tie direction right (<= takes from
a first) and the empty cases are free — the drain loops handle them
without extra code. This shape returns in the exam's ArrayList FRQ
almost every year in disguise.