Logic Masters Deutschland e.V.

Fill the grid with digits from 1 to 4 so that in each marked region each digit occurs exactly once in each row and column. These numbers represent skyscrapers of the corresponding height.

Digits adjacent to another region are also clues for that region. They indicate how many skyscrapers can be seen in the corresponding direction where lower skyscrapers are covered by higher ones. However, only clues in shaded cells are correct, clues in unshaded cells are always incorrect. If a cell is adjacent to two different regions, the clue must be correct for both if it's shaded, or incorrect for both if it's unshaded.