Notes on this puzzle
11 clues around the edge, out of a possible 20, frame this 5×5 grid. 2 heights are already standing inside the grid.
On 2 lines the two opposite clues add up to 6, which fixes exactly where the tallest building stands. The bottom edge carries the most clues (4). 9 edge positions are blank, so parts of the grid are solved from the inside out.
Where to beginTry row 4, column 3 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.