Medium data structure and algorithm practice puzzle.
Given a list of numbers, scale them into the range 0 to 1, rounded to 3 decimals. Subtract the smallest value, then divide by the range (max minus min). The smallest becomes 0 and the biggest becomes 1. If every value is the same, the range is 0, so treat it as 1 and everything becomes 0.
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 Sample Ranking Service, a pipeline you can run and download. See every Software Engineer project.
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