You are asking to write a solver for the skycrapers puzzle. The following is the rule for this puzzle:
Place a number from 1 to $n$ (integers only) into each cell so that each number appears exactly once in each row and column. ($n$ is the number of cells in each row.) Each number represents a skyscraper of its respective height. The numbers outside the grid indicate how many skyscrapers can be seen in the respective row or column from the respective direction; smaller skyscrapers are hidden behind higher ones. In other words, a skyscraper is visible if numbers of all skyscrapers in front of it are slower.