Sudoku Skyscrapers

Sudoku Skyscrapers (also known as Towers) is a game of riddles in which a grid of variable size (in this game you can play 4x4 and 5x5 grids and up to 9x9 in subsequent updates) is a district of a city. The numbers outside the grid indicate how many buildings are visible from that point of view. The aim of the game is to enter the numbers in the grid knowing that in any position of the rows and columns the buildings always have different heights.
For example, in a 4 x 4 pattern, the buildings will have from 1 to 4 floors (numbers from 1 to 4). Remember to use the "small" temporary numbers, that will help you achieve the solution of the scheme.
Have fun!