Fill the grid according to standard Sudoku rules: each row, column, and 3×3 box must contain the digits 1-9 without repetition.
Additionally, imagine that each cell contains a skyscraper with a height equal to its digit (1-9). The numbers outside the grid indicate how many skyscrapers can be seen when looking from that position along the corresponding row or column.
A taller skyscraper blocks the view of shorter skyscrapers behind it. For example, if a row contains the sequence 2, 1, 4, 3, 5, 9, 7, 8, 6 when viewed from the left, only 4 skyscrapers would be visible (heights 2, 4, 5, and 9), because each visible skyscraper must be taller than all skyscrapers before it.
