Clue of One

Easy Used by Smart Hint

A clue of 1 means the tallest building is visible right at that edge — place the max height there.

Cells that establish the pattern
Where the conclusion lands

How it works

The 1 on the left edge says exactly one building is visible looking along the top row.
That's only possible if the very first building is the tallest — everything behind the 4 is hidden.
Place the 4 right at the edge.