Queue Reconstruction - Greedy Insight

Insert tallest people first.

When you insert a tall person, shorter people not yet inserted do not affect their $k$ value. Sort by height descending, then by $k$ ascending. Insert each person at index $k$ in the result. Why this works: when you insert person $(h, k)$, all people already in the result are at least as tall. Inserting at position $k$ means exactly $k$ people in front are taller or equal. Shorter people inserted later slot in without disrupting this.