Skyscrapers

Objective

Fill every cell with a building of height 1 to n so that each row and each column uses every height once, like a latin square. The numbers around the grid are clues: how many buildings you can see looking along that row or column from that edge.

Visibility

• A building is visible if it is strictly taller than every building in front of it.
• Looking left to right at 2, 1, 4, 3 you see two towers: the 2, then the 4. The 1 and 3 are hidden.
• An empty clue means that side has no constraint.

Controls

• Tap a cell, then tap a height on the pad (or press 1 to n).
• A second tap on the same cell cycles through the heights.
• Clear, 0 or Backspace empties the cell. Given starter cells stay locked.
• Right-click or long-press adds a note. Check highlights clashes. Hint fills one correct cell.

Difficulty

• Easy: 4×4, all clues, a couple of given cells
• Classic: 5×5 with some clues hidden
• Hard: 6×6 with fewer clues

Daily challenge

Everyone receives the same seeded city (4×4, 5×5 or 6×6). It resets at midnight UK. The first solve of the day counts for the league. Higher score ranks first: faster times and fewer mistakes score more.