Easy data structure and algorithm practice puzzle.
Games draw far things first so near things paint over them, which is called the painter's algorithm. Given two draw lists already sorted from farthest to nearest by depth, the terrain list a and the sprite list b, return the order to draw them in as a list of "a" and "b". When depths tie, draw from a first so sprites stand on the ground rather than under it. Use two pointers, one into each list, and always take the farther of the two fronts.
Solve it three ways: snap the jigsaw pieces together, fill in the blanks, or type it from scratch against the tests. This one is free.
Every line of the solution comes with a note explaining why it is there, and a step by step replay shows the code running. At level 3, where you type it yourself, you can ask for an AI mock interview on this problem that ends with a hiring manager's scorecard.
Then grow it into a real project with the Software Engineer button: this puzzle becomes the Entity Reconciler, a pipeline you can run and download. See every Software Engineer project.
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