Rules: Place a digit from 1 to 9 in each empty cell so that each digit appears exactly once in each row, column and 3x3 outlined box.
There are some arrow shapes in the grid. The sum of the digits along the path of each arrow must equal the digit in the circled cell. Digits may repeat along an arrow.
Each digit in the grid represents the height of the skyscraper in each cell. The digits outside the grid indicate the number of skyscrapers seen from the corresponding direction.