Rules:

This puzzle has Parks (empty cells). The goal is to fill in each cell with numbers from 1 to N-(No. of Parks), where N is the size of the puzzle's side.

Each column and each row have exactly one of each number and N parks.

The numbers along the edge of the puzzle indicate the number of buildings which you would see from that direction if there was a series of skyscrapers with heights equal the entries in that row or column.

For example: if the grid is 4 and if the first number is 4, you will see only one skyscraper (the one with 4 floors) because it hides all other skyscrapers (those with 1, 2, 3 floors).

This puzzle has a Diagonal Variant. Every diagonal line contains each of the digits only once.