Medium data structure and algorithm practice puzzle.
Given a linked list, passed in as its values, and k, rotate it right so the last k nodes move to the front. Take k mod the length first, since rotating by the full length changes nothing. Then the answer is the last k values followed by the rest. On a real linked list, you'd join the end to the front to make a loop, then cut it in the right place.
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 Trade LRU Service, a pipeline you can run and download. See every Software Engineer project.
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