Medium data structure and algorithm practice puzzle.
Auto-aim locks on to the closest enemies. Given the player's position, a list of enemy positions [x, y] and k, return the indexes of the k nearest enemies, nearest first, breaking ties by the lower index. Compare squared distances, dx * dx + dy * dy. They rank enemies in the same order as real distances, and you skip the square root. Only the nearest k matter, so the rest never need to be put in order.
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 Parser, a pipeline you can run and download. See every Software Engineer project.
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