Notes on this puzzle
11 clues around the edge, out of a possible 20, frame this 5×5 grid. No heights are given inside the grid; the edge clues do all the work.
There is 1 clue of 1 around the frame; the first cell beside each of them must hold a 5. The left edge carries the most clues (5). 9 edge positions are blank, so parts of the grid are solved from the inside out.
Where to beginTry row 2, column 1 first: its row and column clues decide it without any other help. Remember that a clue of k keeps the tallest building at least k−1 cells away from that edge.