Skyscrapers — Quick rules

Goal of the game

Place building heights so that every row and column uses the required numbers and every edge clue sees exactly the stated number of buildings.

On an N×N grid, use heights 1 through N once in each row and column. Keep any given heights.
Look from an edge clue straight along its row or column. A building is visible only if it is taller than every building before it from that viewpoint.
An edge clue counts visible buildings, not their total height. A blank edge supplies no clue.
A taller building hides smaller ones behind it, but cannot hide an even taller building farther along.