Case: Silhouette

Clue of $1$

A half-lane with a clue of $1$ must have the $N$ -skyscraper in the head cell.


1


1	N

Examples

Case 1


		1



						1


1
5


	5	1

Explanation

A $1$ -clue means we can only see 1 skyscraper. The only way to achieve this is if we see the tallest skyscraper (the $N$ -skyscraper), obscuring all the rest behind it.

If we picked any other skyscraper as our 1 visible skyscraper, we’d still be able to see the $N$ -skyscraper behind it as well, since the $N$ -skyscraper is taller than all other skyscrapers.