Codility_ Cover "Manhattan skyline" using the minimum number of rectangles. https://app.codility.com/programmers/lessons/7-stacks_and_queues/stone_wall/
It took me a very long time understanding what the problem was looking for. If interested in my comments and approach I would like to invite you to read the associated post in my blog:
https://www.johncanessa.com/2021/11/18/stone-wall/
Keep in mind that one of the best ways to learn and refresh your knowledge is to read and experiment. Remember that practice makes perfect.
Enjoy;
John